bzielinski@google.com cros-edu-eng@google.com The result of adding a cast sink to the media router sink list via the AccessCodeCastSinkService when discovering it using an access code. Recorded after the cast sink is added. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The result of adding a cast sink to the media router sink list via the AccessCodeCastSinkService when the device was remembered due to device policy. Recorded after the cast sink is added. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The selected cast mode when a cast session is successfully started (ResultCode::OK) after a user enters an access code. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The duration in seconds an access code device will stay in the list of cast devices. Recorded on successful creation of a cast session to an access code device. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The count of cast devices which have been successfully remembered via the access code cast sink service. Recorded when the browser starts, and any time the network changes. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The count of times that a local cast mirroring session is frozen, or paused, during its duration. Recorded at the end of a cast mirroring session. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds that a local cast mirroring session is frozen, or paused, until it is resumed or ended. Recorded when the session is resumed, or when the session ends. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds that it takes to connect to a new device. It is the combination of connecting to our server, validating the access code, constructing a cast device, opening a channel to that device, and then waiting for success. It is only recorded if the request was successful; not recorded for non-local routes. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The discovery type of the associated sink and the cast media source for an access code route. Recorded when at the start of a local access code route. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds that a route to an access code device lasts. Recorded at the end of a local access code route; not recorded for non-local routes. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds that it takes to connect to a saved device. It is a combination of the time to request a mirroring route + waiting for a success. It is only recorded if the request was successful; not recorded for non-local routes. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds for the user to input an access code after the UI is enabled for a cast attempt. Recorded when the user presses enter or the submit button after typing an access code. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The count of ACCESS_CODE_NOT_FOUND errors received while the AccessCodeCastDialog is open, correlating to the number of times a user typed an incorrect access code. Recorded after the dialog is closed. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The amount of time in milliseconds that the dialog is loading while attempting to cast to a new device via access code. Recorded after a cast attempt completes, and does not depend on whether the attempt was successful or ended in error. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The reason why the Access Code Cast dialog closed. Recorded when the Access Code Cast dialog closes. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The length of time for the AccessCodeCast dialog to finish loading after instantiation. Recorded after the UI creates a page handler object. Logged only on desktop platforms. bzielinski@google.com cros-edu-eng@google.com The location from which the AccessCodeCast dialog is opened. Recorded after the dialog opens. Only logged on desktop platforms. ryanchung@google.com Records the result of the Cast certificate verification on the Cast sender. jophba@chromium.org media-dev-uma@chromium.org Records any flags observed on the Cast channel used to launch a Cast session. A single channel may have multiple flags, and each flag is logged as a separate count. Warning: this histogram was expired from 2025-11-16 to 2026-02-02; data may be missing. ryanchung@google.com Records whether the correct nonce challenge was in the Cast receiver's response. ryanchung@google.com Records whether the signature returned by the Cast receiver is verifiable with the challenge and device certificate. jophba@chromium.org openscreen-eng@google.com Records the location when users interact with the RemotePlayback API on Clank. Please note, this metric does not show whether a session is started or stopped and does not include RemotePlayback sessions initiated through the Cast SDK. jophba@chromium.org openscreen-eng@google.com Indicates whether initialization of a video encode accelerator for Cast sender was successful. Warning: this histogram was expired from 2021-10-17 to 2022-12-15; data may be missing. jophba@chromium.org openscreen-eng@google.com Records which audio codec was negotiated during a mirroring session. jophba@chromium.org openscreen-eng@google.com Records the currently set video bit rate during a Cast Streaming mirroring session. This metric is subsampled every 500 frames. jophba@chromium.org openscreen-eng@google.com Records which video codec was negotiated during a mirroring session. Records the selected encoder configuration whenever a negotiation between the sender and receiver devices is completed. This configuration includes the encoder codec as well as whether it is software or hardware based. jophba@chromium.org openscreen-eng@google.com Records which video codec was negotiated during a mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the average {CastStreamingSenderAudioVideo} latency in milliseconds for capturing frames. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the average time required to encode {CastStreamingSenderAudioVideo} frames, in milliseconds. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the average {CastStreamingSenderAudioVideo} latency in milliseconds end to end, from the beginning of capturing a frame to when the frame is played out on the receiver. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the average {CastStreamingSenderAudioVideo} latency in milliseconds from sender to receiver. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records number of {CastStreamingSenderAudioVideo} packets that exceeded the playout delay as a percentage of all packets. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the percentage of {CastStreamingSenderAudioVideo} frames that are reported as late, and therefore dropped by the sender, during a cast mirroring session. Recorded at the end of a cast mirroring session. Logged on all desktop platforms. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records number of {CastStreamingSenderAudioVideo} packets that had to be retransmitted as a percentage of number of packets sent. Histogram is recorded at the end of the mirroring session. anasr@google.com bzielinski@google.com jophba@chromium.org openscreen-eng@google.com cros-edu-eng@google.com Records the {CastStreamingSenderAudioVideo} packet transmission bitrate in kbps during a Cast Streaming session. Histogram is recorded at the end of the mirroring session. jophba@chromium.org openscreen-eng@google.com Records the reason when an frame is dropped during a Cast Streaming session. jophba@chromium.org openscreen-eng@google.com Records the total percentage of frames dropped for a given Cast Streaming session. vikassoni@chromium.org media-dev-uma@chromium.org Error codes to handle AImage and AImageReader api calls. This is recorded when AImageReader acquireNextImage or acquireLatestImage is called and the returned code is other than AMEDIA_OK. This histogram was enabled in the past and became absolete on 2018-11-25. NOTE: metric expired from 2024-12-15 to 2025-07-07. vasilyt@chromium.org media-dev-uma@chromium.org Logs whether we use MediaCodec or MediaPlayer (aka StreamTexture path). This is recorded when AImageReader acquireNextImage or acquireLatestImage is called. vasilyt@chromium.org media-dev-uma@chromium.org Logs whether AImageReader provided an acquire fence in acquireNextImage or acquireLatestImage. Logged once for each successfuly acquired frame. philyan@chromium.org media-dev-uma@chromium.org Records whether playback is paused when a headset unplug event is received. If the feature flag NoPauseMediaOnHeadphoneUnplug is enabled, this will record false. Otherwise, it will record true. Only recorded when a headset unplug event (AudioManager.ACTION_AUDIO_BECOMING_NOISY) is received while the media notification is active and not already paused. philyan@chromium.org media-dev-uma@chromium.org Records the duration of time between when playback is paused due to a headset unplug event (AudioBecomingNoisy) and when it is next resumed. Only recorded when the user manually resumes playback after the auto-pause. Not recorded if the user pauses manually before resuming, or if the notification is cleared. philyan@chromium.org media-dev-uma@chromium.org Records the result of the audio focus request on Android. vasilyt@chromium.org liberato@chromium.org media-dev-uma@chromium.org Android: Whether we successfuly got ColorSpace from MediaCodec or not. Recorded each time output format changes from MediaCodec. sobek@google.com media-dev-uma@chromium.org Recorded when the MediaCodec instance is released (`ReleaseCodec`). It will be true if this MediaCodec instance encountered an input buffer that exceeded the max input buffer size configured by the codec (`max_input_size_`). It will be false otherwise. This helps track the frequency of heuristic failures for input buffer estimations during MediaCodec decoder configuration. evliu@google.com media-dev-uma@chromium.org Records how long more than one tab is audible at the same time. The concurrent tabs might change during this period. The time recorded starts when the browser goes from one to two audbile tabs and stops when it is back below two. Warning: this histogram was expired from 2020-09-05 to 4-18-22; data may be missing. evliu@google.com media-dev-uma@chromium.org Records how many tabs were audible when a new tab started to be audible. Warning: this histogram was expired from 2020-09-05 to 4-18-22; data may be missing. evliu@google.com media-dev-uma@chromium.org Records how many tabs are audible at the same time during the session. It is recording the maximum audible tab count everytime it increases. In other words, a session with N concurrent audible tabs will record entries from 1 through N exactly once. Warning: this histogram was expired from 2020-09-05 to 4-18-22; data may be missing. tguilbert@chromium.org media-dev-uma@chromium.org The number of frames delivered in each AAudio data callback for {Direction} streams. Logged sub-sampled (once every 100 callbacks) to evaluate variable callback dynamics. tguilbert@chromium.org media-dev-uma@chromium.org The number of callback size transitions per 1000 callbacks for {Direction} streams. Logged on stream close for streams lasting longer than 10 seconds. tguilbert@chromium.org media-dev-uma@chromium.org The size (magnitude of deviation from expected callback interval) of a timestamp discontinuity for AAudio input streams. Logged whenever a discontinuity is detected (i.e. the actual interval differs from the expected interval by more than 10% of the callback duration). tguilbert@chromium.org media-dev-uma@chromium.org The size (magnitude of deviation from expected callback interval) of a timestamp discontinuity for AAudio input streams. Logged whenever a discontinuity is detected (i.e. the actual interval differs from the expected interval by more than 10% of the callback duration). This V2 version tracks timestamps from the start of captured audio buffers (the oldest sample, as expected by the media pipeline) rather than the most recent sample, fixing errors caused by variable-sized callbacks. tguilbert@chromium.org media-dev-uma@chromium.org The number of discontinuities in OnData() timestamps per 10 second interval for AAudio input streams. A discontinuity is counted if the timestamp differs from the expected timestamp by more than 10% of the callback duration. Logged periodically every 10 seconds while the stream is running. Streams shorter than 10 seconds are ignored. tguilbert@chromium.org media-dev-uma@chromium.org The number of discontinuities in OnData() timestamps per 10 second interval for AAudio input streams. A discontinuity is counted if the timestamp differs from the expected timestamp by more than 10% of the callback duration. Logged periodically every 10 seconds while the stream is running. Streams shorter than 10 seconds are ignored. This V2 version tracks timestamps from the start of captured audio buffers (the oldest sample, as expected by the media pipeline) rather than the most recent sample, fixing errors caused by variable-sized callbacks. kawasin@google.com tguilbert@chromium.org The buffer size in frames of an AAudio {Direction} stream got by `AAudioStream_getBufferSizeInFrames()` and {AudioLatencyTag}. Logged when an AAudio stream is opened. tguilbert@chromium.org media-dev-uma@chromium.org The frames per burst of an AAudio {Direction} stream retrieved by `AAudioStream_getFramesPerBurst()` and {AudioLatencyTag}. Logged when an AAudio stream is opened. tguilbert@chromium.org media-dev-uma@chromium.org Whether the value returned by `AAudioStream_getFramesPerBurst()` changed bewtween when an {Direction} stream was opened and when it was closed. Logged when an AAudio stream is closed. kawasin@google.com tguilbert@chromium.org media-dev-uma@chromium.org The number of frames per data callback for an AAudio stream got by `AAudioStream_getFramesPerDataCallback()` and {AudioLatencyTag}. Logged when an AAudio stream is opened. The requested value by the client is logged as `Media.Audio.Android.RequestedInputFramesPerBuffer` or `Media.Audio.Android.RequestedOutputFramesPerBuffer`. Note that `Media.Audio.Android.AAudioFramesPerDataCallback` can be different from the actual buffer size used by the stream on Android which is logged as `Media.Audio.Android.AAudioBufferSizeInFrames`. mjel@google.com tguilbert@chromium.org media-dev-uma@chromium.org For every AAudio {Direction} stream that is opened without resulting in an internal AAudio error and with a non-default device requested, records if setting the device ID was a {Result}. This operation is considered successful if the requested device (passed to AAudioStreamBuilder_setDeviceId) is the same as the actual device assigned to the stream (received via AAudioStream_getDeviceId). tguilbert@chromium.org media-dev-uma@chromium.org Logs the number of glitches reported by `AAudioStream_getXRunCount()` in a regular 10s interval. Logged once every 10s, for each input stream. Note: glitch counts cannot be mapped back to a number of frames or a duration. There is no way to assess the severity of glitches, only the number of glitches. Note: Some input devices do not support `getXRunCount()`, and always report 0 glitches in that case. tguilbert@chromium.org media-dev-uma@chromium.org Logs the number of glitches reported by `AAudioStream_getXRunCount()`, when we've accumulated fewer than 10s of data. This covers all input streams who are closed within 10s of being created, as well as the last few seconds of any longer-lived stream's lifetime. Logged on stream closure, for each input stream. Note: glitch counts cannot be mapped back to a number of frames or a duration. There is no way to assess the severity of glitches, only the number of glitches. Note: Some input devices do not support `getXRunCount()`, and always report 0 glitches in that case. tguilbert@chromium.org media-dev-uma@chromium.org Logs the number of glitches reported by `AAudioStream_getXRunCount()` in a regular 10s interval. Logged once every 10s, for each output stream. Note: glitch counts cannot be mapped back to a number of frames or a duration. There is no way to assess the severity of glitches, only the number of glitches. tguilbert@chromium.org media-dev-uma@chromium.org Logs the number of glitches reported by `AAudioStream_getXRunCount()`, when we've accumulated fewer than 10s of data. This covers all output streams who are closed within 10s of being created, as well as the last few seconds of any longer-lived stream's lifetime. Logged on stream closure, for each output stream. Note: glitch counts cannot be mapped back to a number of frames or a duration. There is no way to assess the severity of glitches, only the number of glitches. mjel@google.com tguilbert@chromium.org media-dev-uma@chromium.org For every call to SystemMonitor::ProcessDevicesChanged indicating a change in available audio devices, records whether it was caused by devices being added or removed. dvalenzuela@google.com openscreen-eng@google.com Records the AudioDevice channel masks that are supported by Android automotive, but not yet mapped to a corresponding media::ChannelLayout. To interpret these numbers as AudioFormat.channelMasks, see: https://developer.android.com/reference/android/media/AudioFormat#channelMask kawasin@google.com tguilbert@chromium.org media-dev-uma@chromium.org The preferred output buffer size in frames for an audio output stream calculated from OS provided buffer size on Android. This is for audio output streams that {AudioLatencyTagWithInvalidInputParams}. Logged when GetPreferredOutputStreamParameters() is called. This value is usally used by the client to calculate the buffer size in frames for an audio output stream which is logged as `Media.Audio.Android.RequestedOutputFramesPerBuffer`. kawasin@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@chromium.org The number of frames per data callback for an audio input stream requested by the client and {AudioLatencyTag}. Logged on stream creation. `Media.Audio.Android.AAudioFramesPerDataCallback.Input` logs the actual values used in an AAudio input stream. kawasin@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@chromium.org The number of frames per data callback for an audio output stream requested by the client and {AudioLatencyTag}. Logged on stream creation. `Media.Audio.Android.AAudioFramesPerDataCallback.Output` logs the actual values used in an AAudio output stream. dvalenzuela@google.com openscreen-eng@google.com Records the AudioDevice channel masks that are supported by Android automotive. These only include masks that are mapped to a corresponding media::ChannelLayout. To interpret these numbers as AudioFormat.channelMasks, see: https://developer.android.com/reference/android/media/AudioFormat#channelMask evliu@google.com dalecurtis@chromium.org media-dev-uma@chromium.org Records the autoplay source of audios. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Whether missing callbacks where detected during audio capture. Logged when AudioInputDevice is stopped. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com The number of captured audio frames that is provided by the operating system in each callback. Typically, Chrome will want to use a 10 ms buffer (e.g. 480 frames for a sample rate of 48 kHz), but the OS may decide to capture e.g. 256 frames of audio at a time. If the desired frame size is used, the emitted value is special-cased to be 0. This histogram then shows how frequent it is that the desired number of frames is used and if not, the number of frames used in practice. The number of frames per callback is normally constant or very rarely changed throughout the lifetime of the audio stream. The first value that differs from the desired value is stored and logged when an audio input stream is closed. Any further differences during the lifetime will be ignored. olka@chromium.org saza@chromium.org webrtc-audio-uma@google.com This histogram measures the duration of every input stream, as seen from the renderer. It counts from when it has been successfully started, until it is stopped. Streams that fail to start are not logged. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com A boolean that reflects whether or not an error was reported during audio capture for a low latency stream. lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org The SampleFormat macOS chooses when initializing audio input capture. Used to determine which proportion of devices do not support Float32 and fallback to SignedInt16. This is logged once per stream initialization. This accounts for both regular input streams and VoiceProcessing input streams. There are only two valid options, F32 and S16. All other cases will be recorded as kUnknownSampleFormat. brandstrom@chromium.org webrtc-audio-uma@google.com Measures the time required to retrieve the ApplicationAudioCaptureId for a given process identifier on macOS. Logged for each call to GetApplicationAudioCaptureIdForProcess() with the status variant (Success or Failure). toprice@chromium.org video-cmi-apis@google.com webrtc-audio-uma@google.com The time from the first microphone access failure due to blocked system permission before the last browser restart to startup after browser restart. Logged once at browser startup if the system permission then is allowed. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. toprice@chromium.org video-cmi-apis@google.com webrtc-audio-uma@google.com The time from the last microphone access failure due to blocked system permission before the last browser restart to startup after browser restart. Logged once at browser startup if the system permission then is allowed. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. toprice@chromium.org video-cmi-apis@google.com webrtc-audio-uma@google.com The Mac system permission state for microphone. Logged once at browser startup. For more information on the values, see https://developer.apple.com/documentation/avfoundation/avauthorizationstatus. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. toprice@chromium.org video-cmi-apis@google.com webrtc-audio-uma@google.com The Mac system permission state for microphone. Logged once at browser startup if there was a failure accessing the microphone due to blocked system permission before the last browser restart. For more information on the values, see https://developer.apple.com/documentation/avfoundation/avauthorizationstatus. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. toprice@chromium.org video-cmi-apis@google.com webrtc-audio-uma@google.com The Mac system permission state for microphone at the time of a user media request. Logged when the system permission is checked. If the permission is "not determined" this is logged, permission is requested, and the resulting permission (from the user response) is also logged. For more information on the values, see https://developer.apple.com/documentation/avfoundation/avauthorizationstatus. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. saza@chromium.org devicentepena@webrtc.org webrtc-audio-uma@google.com A boolean that reflects whether or not an ML model for neural residual echo estimation is available. Logged when an audio processor with echo cancellation is constructed. Logging is restricted to when audio service ML model delivery is enabled. tguilbert@chromium.org olka@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Maximum size (in buffers) of the unprocessed data queue, reached over a sampling interval (1000 callbacks). Not logged for streams received less than 1000 callbacks. tguilbert@chromium.org olka@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Number of times over a sampling interval (1000 callbacks) a ProcessingAudioFifo has overflowed and dropped buffers. Capped at 100 (1/10 of all callbacks). Not logged for streams received less than 1000 callbacks. mfoltz@chromium.org olka@chromium.org webrtc-audio-uma@google.com Indicates if SCShareableContent enumeration has timed out during a call to SCKAudioInputStream::Open(). The timeout exists to prevent a deadlock if the API is misbehaving. We do not expect any timeouts under normal conditions. Warning: this histogram was expired from 2025-12-28 to 2026-02-02; data may be missing. mfoltz@chromium.org olka@chromium.org webrtc-audio-uma@google.com Measures the time required for SCShareableContent enumeration (displays and open applications/windows) when calling SCKAudioInputStream::Open(). The duration can vary based on the amount of applications and windows open on the system. This enumeration is a blocking operation, and as such should complete as fast as possible. If metrics show long times, the operation might have to be made asynchronous. Warning: this histogram was expired from 2025-12-28 to 2026-02-02; data may be missing. mfoltz@chromium.org olka@chromium.org webrtc-audio-uma@google.com Error codes reported by ScreenCaptureKit in SCKAudioInputStream::OnStreamError() during stream setup or while streaming samples. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com When AudioInputDevice is stopped, this stat is recorded with whether an error callback was ever received over IPC, and in that case whether the error occurred during or after stream creation. henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com The absolute time difference in milliseconds between a default QPC-based timestamp and a timestamp from TimeTicks::Now(). By default, the difference will be small and correspond to the size of the audio capture buffer which is about 10 milliseconds. It can however be very large on some devices, e.g. when using RDP. If the difference is larger than 500 milliseconds, so-called fake audio capture timestamps (based on TimeTicks::Now()) will be utilized. This value is logged once per audio input stream session at the first audio callback. lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org This is the SampleFormat the Windows Audio Engine returns as its preferred format when we open an Audio Input Stream. This is recorded everytime a user decides to record audio (e.g. record via microphone). This is recorded once per Input Stream, notably recorded at Stream Open rather than Stream Initialization. lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org This is the SubFormat.Data1 (i.e. wFormatTag) the Windows Audio Engine returns as its preferred format when we open an Audio Input Stream, recorded only when the format does not map to a known media::SampleFormat. This is potentially recorded everytime a user decides to record audio (e.g. record via microphone). This is recorded once per Input Stream, notably recorded at Stream Open rather than Stream Initialization. henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Logs whether audio capture timestamps on Windows are fake or not. By default QPC-based timestamps provided by native audio APIs are utilized. In some cases the QPC-based timestamps differ a lot compared with TimeTicks::Now() timestamps and this can lead to issues (see http://crbug.com/1439283). If an absolute difference larger than 500 msec between these two types of timestamps is detected, we fall back to using TimeTicks::Now() and these timestamps are called fake timestamps. We expect that usage of fake timestamps will be low. This value is logged once per audio input stream session at the first audio callback. henrika@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logs whether the attempt to acquire an input audio client asynchronously timed out or not. A timeout corresponds to a waiting time which exceeds 10 seconds. Logged once when an input audio stream is opened and the specified device ID is a process loopback device. Only supported on Windows. olka@chromium.org henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com The number of glitches that were detected at the OS level while an audio input stream was active. A glitch in this case corresponds to a certain error code from the IAudioCaptureClient::GetBuffer() API: AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY. This value is logged every 1000 OS callbacks on Windows. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com Errors from IAudioClient::Initialize() in WASAPIAudioInputStream::InitializeAudioEngine on Windows that are related to the audio format. Each error is split by whether format conversion was used or not. Warning: this histogram was expired from 2022-10-17 to 2022-10-18; data may be missing. henrika@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logs true if IAudioClient::Initialize() failed with E_ACCESSDENIED in WASAPIAudioInputStream::InitializeAudioEngine on Windows, indicating that audio capture was blocked by system permissions. Logged once per initialization attempt. henrika@chromium.org olka@chromium.org tommi@chromium.org guidou@chromium.org webrtc-audio-uma@google.com Error codes from IAudioClient::Initialize() in WASAPIAudioInputStream::InitializeAudioEngine on Windows. E_ACCESSDENIED is intentionally excluded and is tracked by Media.Audio.Capture.Win.SystemPermissionDenied instead. gudiou@chromium.org olka@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Success/error cases for opening an audio input stream on Windows. lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org The HRESULT code for an error when initializing for process loopback capture. This is recorded only when initialization fails and the device is a process loopback device. E_ACCESSDENIED is intentionally excluded and is tracked by Media.Audio.Capture.Win.SystemPermissionDenied instead. henrika@chromium.org olka@chromium.org webrtc-audio-uma@google.com This histogram records the time it takes to activate an audio client asynchronously, which occurs on the audio.CrUtilityMain thread in the AudioService process. Logged once when an input audio stream is successfully opened and the specified device ID is a process loopback device. Only supported on Windows and when Media.Audio.Capture.Win.GetAudioClientTimedOut is false. henrika@chromium.org olka@chromium.org webrtc-audio-uma@google.com Supported audio effect types detected for audio input devices. Emitted each time a client requests the preferred audio parameters for a specified device but also each time a client opens an audio input stream where an AEC effect is requested by the input parameters. Only supported on Windows and when the EnforceSystemEchoCancellation flag is enabled. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Error codes reported by the NotifyStreamError function in CrasInputStream. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logged at each call to CrasInputStream::Open to indicate any errors. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logged at each call to CrasInputStream::Start to indicate any errors. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Error codes reported by the NotifyStreamError function in CrasUnifiedStream. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logged at each call to CrasUnifiedStream::Open to indicate any errors. peah@chromium.org hychao@chromium.org olka@chromium.org webrtc-audio-uma@google.com Logged at each call to CrasUnifiedStream::Start to indicate any errors. jophba@chromium.org dalecurtis@chromium.org media-dev-uma@chromium.org When there is a codec delay mismatch between the container and the decoder for the OpusAudioDecoder, reports the absolute difference in value. jophba@chromium.org dalecurtis@chromium.org media-dev-uma@chromium.org Records the audio decoder type used for a playback session. Recorded when the metrics provider is destructed. lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org Records the outcome of the IamfAudioDecoder initialization, including success or specific failure reasons. It is recorded once per decoder during initialization within IamfAudioDecoder::Initialize(). lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org Records the number of spatial audio channels in the input IAMF stream. It is recorded once per decoder during successful initialization within IamfAudioDecoder::Initialize(). lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org Records whether the IAMF decoder upmixed, downmixed, or passed through the input channel layout to the requested output layout. It is recorded once per decoder during successful initialization within IamfAudioDecoder::Initialize(). lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org Records the IAMF output layout requested or configured by the decoder. It is recorded once per decoder during successful initialization within IamfAudioDecoder::VerifyStreamParameters(). lowkey@google.com tguilbert@chromium.org media-dev-uma@chromium.org Records the total duration of audio successfully decoded by the IamfAudioDecoder in a single session. It is recorded once per decoder when the decoder is destroyed within IamfAudioDecoder::~IamfAudioDecoder(), provided there was at least one successful temporal unit decoded. henrika@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Reports the audio delays seen by the audio::InputController::OnData() callback for a source of type {AECType}. henrika@chromium.org webrtc-audio-uma@google.com Indicates if audio capturing did start after stream startup was requested. Sampled once, a few seconds after a stream has been asked to start. {MacAudioInputVariants} henrika@google.com fhernqvist@google.com webrtc-audio-uma@google.com Reports if a loopback AEC reference audio input stream was closed due to a runtime error or not. Only supported on Windows and Mac. henrika@google.com fhernqvist@google.com webrtc-audio-uma@google.com Reports success/error cases for opening a loopback AEC reference audio input stream on Windows or Mac. This is a V2 metric replacing Media.Audio.LoopbackReference.OpenResult to include the new STREAM_OPEN_DEVICE_REMOVED_ERROR outcome. agpalak@chromium.org dalecurtis@chromium.org webrtc-audio-uma@google.com Reports the number of occurences of null output dictionary when AudioObjectGetPropertyData for kAudioAggregateDevicePropertyComposition is called. This is equivalent to the number of crashes that were reported in crbug.com/1428619. kron@chromium.org webrtc-audio-uma@google.com Reports the number of occurences of private aggregate devices where the dictionary entry for kAudioAggregateDeviceIsPrivateKey is successfully interpreted as a {Type}. Recorded for each call to IsPrivateAggregateDevice() if the AudioObjectID is of type kAudioDeviceTransportTypeAggregate and there is a dictionary. This histogram is used to determine the type of the value in the dictionary for kAudioAggregateDeviceIsPrivateKey. If no occurences of type Number are detected, we can remove the code path that parses the dictionary as a number. kron@chromium.org webrtc-audio-uma@google.com Reports the number of callbacks where the channel count in the sample callback did not match the channel count of the stream. The histogram is recorded when the capture is stopped. kron@chromium.org webrtc-audio-uma@google.com Reports the number of callbacks where the number of frames in the sample callback did not match the frames per buffer of the stream. The histogram is recorded when the capture is stopped. kron@chromium.org webrtc-audio-uma@google.com This metric reports whether host time was provided in the sample callbacks. It also tracks recoveries, defined as a callback with host time occurring after a callback without host time. The histogram is recorded when the capture is stopped. kron@chromium.org webrtc-audio-uma@google.com Reports the IsAlive property of the CoreAudio tap's aggregated device. The histogram is recorded in the property listener's callback when the IsAlive property is reported to have changed. kron@chromium.org webrtc-audio-uma@google.com Reports the duration of the operation {Operation} in CatapAudioInputStream. The duration is measured from the time the operation is called until the operation completes with a success or failure. The result is immediately logged. This histogram tracks the duration of operations that result in a {Status}. kron@chromium.org webrtc-audio-uma@google.com Reports the status of the operation Close in CatapAudioInputStream. Failures are recorded directly after the failure occurs. The histogram is recorded immediately after the operation completes, either with a success or failure. kron@chromium.org webrtc-audio-uma@google.com Reports the status of the operation Open in CatapAudioInputStream. Failures are recorded directly after the failure occurs. The histogram is recorded immediately after the operation completes, either with a success or failure. kron@chromium.org webrtc-audio-uma@google.com Reports the status of the operation {Operation} in CatapAudioInputStream. Failures are recorded directly after the failure occurs. The histogram is recorded immediately after the operation completes, either with a success or failure. tguilbert@chromium.org media-dev-uma@chromium.org The reported hardware latency, used to adjust timestamps for A/V sync. Logged once per low-latency input stream creation (AUAudioInputStream only), or once per output stream creation. brandstrom@chromium.org webrtc-audio-uma@google.com If the device reports that system noise supression is available. yuhsuan@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Logged at each call to AudioManagerBase::MakeAudioInputStream to indicate any errors. yuhsuan@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Logged at each call to AudioManagerBase::MakeAudioOutputStream to indicate any errors. henrika@chromium.org dalecurtis@chromium.org webrtc-audio-uma@google.com Logs the exact COM HRESULTs encountered during various phases of the Windows WASAPI audio output stream lifecycle (Open, Start, Stop, Render, and Run). This is version 2 of the metric, which strictly logs HRESULTs instead of mixing them with raw Win32 errors. Note on overlap between Run and Render: There is an intentional overlap for fatal rendering errors. If a fatal error (like failing to get the endpoint buffer) occurs during the rendering pass, it is logged to the Render histogram. Because this fatal error also causes the background thread to terminate, the exact same HRESULT is subsequently logged to the Run histogram. The Render histogram captures ALL rendering errors (including non-fatal ones that do not kill the thread). The Run histogram acts as a catch-all for whatever killed the background thread (including fatal Render errors as well as thread synchronization failures). guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Time delta between the moment output device authorization request is received by the browser and the moment its processessing is finished (and reply is to be sent back to the renderer if IPC is not closed yet). olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com Health status of the mixed playback. Recorded when mixed playback stopped or failed to start. olka@chromium.org saza@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com Number of times over a sampling interval (1000 callbacks) when the mixing callback took longer than the playback buffer duration to finish. Capped at 100 (1/10 of all callbacks). Not logged if the mixer was called less than 1000 times. Warning: this histogram was expired from 2025-11-17 to 2025-12-01; data may be missing. olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com Health status of each output stream managed by mixer. Recorded when the stream is closed. olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com A path OutputDeviceMixerManager uses to create an output stream. saza@google.com olka@chromium.org webrtc-audio-uma@google.com The time, in milliseconds, between when a block of audio is read from the soundcard and when it's presented to the audio processor. Used in calculating the total system delay for the audio processor. saza@chromium.org olka@chromium.org webrtc-audio-uma@google.com The variance of the capture delay in milliseconds (see Media.Audio.Processing.CaptureDelayMs). Logged once every second and calculated over the past second of data. saza@chromium.org olka@chromium.org webrtc-audio-uma@google.com The time, in milliseconds, between when a block of audio is presented to the audio processor and the time it's played out on the soundcard. Used in calculating the total system delay for the audio processor. saza@chromium.org olka@chromium.org webrtc-audio-uma@google.com The variance of the render delay in milliseconds (see Media.Audio.Processing.RenderDelayMs). Logged once every second and calculated over the past second of data. saza@chromium.org olka@chromium.org webrtc-audio-uma@google.com The estimated total audio system delay presented to the audio processor. The sum of the individual capture and render delays at similar points in time. saza@chromium.org olka@chromium.org webrtc-audio-uma@google.com The variance of the total delay in milliseconds (see Media.Audio.Processing.TotalDelayMs). Logged once every second and calculated over the past second of data. henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Whether the capture device supports raw audio capture or not. Emitted when the audio input stream is closed but only on Windows platforms. Only uploaded for the case when analog AGC is enabled, i.e., for WebRTC-based audio input streams. olka@chromium.org guidou@chromium.org webrtc-audio-uma@google.com The number of frames audio is actually rendered at if the number is different from the desired number of frames. If the desired frame size is used, this value will be 0. Typically, Chrome will want to use a 10ms buffer (e.g. 480 frames for a sample rate of 48kHz), but we might have to render audio 256 frames at a time. This histogram gives us an indication as to how frequent that is and what buffer sizes are used in practice. This value is logged when an audio output stream is stopped. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The time spent to get audio data from the source. For WebRTC, it's the time spent in WebRtcAudioRenderer::SourceCallback. Logged every function call, which is every 10 ms. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The maximum time spent to get audio data from the source during a session. For WebRTC, it's the time spent in WebRtcAudioRenderer::SourceCallback. A session is between Start() and Stop() of WebRtcAudioRenderer. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. olka@chromium.org henrika@chromium.org webrtc-audio-uma@google.com Similar to Media.Audio.OutputDeviceAuthorizationTime, this histogram measures the time required for device authorization, but it is measured on the renderer side when AudioOutputDevice calls RequestDeviceAuthorization on the IO thread until it receives OnDeviceAuthorized, also on the IO thread. Note that an authorization timeout will cause OnDeviceAuthorized to be called, so for platforms that use a timeout, very few times will be above the timeout value. Warning: this histogram was expired from 2020-04-05 to 2021-06-04; data may be missing. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Whether audio output device timed out waiting for authorization reply from the browser side. dalecurtis@chromium.org olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com The time delta from an AudioOutputDevice sending its first PlayStream message to it getting its first data callback. dalecurtis@chromium.org guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Device status received in response to device authorization request. olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com This histogram measures the duration of every output stream, as seen from the renderer. It counts from when it has been successfully started, until it is stopped. Streams that fail to start are not logged. dalecurtis@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com When AudioOutputDevice is stopped, this stat is recorded with whether an error callback was ever received over IPC, and in that case whether the error occurred during or after stream creation. Expired in Apr 2020 and re-enabled in May 2021. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The delay between audio being delivered to the OS-specific implementation of AudioOutputStream and the audio being played out by the speakers. Reported every time the AudioOutputStream calls AudioSourceCallback::OnMoreData. jophba@chromium.org media-dev-uma@chromium.org Records the error code associated with a failed Symphonia audio decoder decoding attempt. jophba@chromium.org media-dev-uma@chromium.org Records the status code returned by the Symphonia audio decoder for each initialization attempt. jophba@chromium.org dalecurtis@chromium.org media-dev-uma@chromium.org Reports the number of frames in a PCM packet that was larger than the static buffer used for decoding. evliu@google.com chrome-media-ux@google.com Logged when a user clicks on the audio indicator button in the tab strip. Logs true if the click mutes the tab and false if the click unmutes the tab. olka@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Device status received during TrackAudioRenderer initialization. This is a specific case of Media.Audio.Render.OutputDeviceStatus histogram. olka@chromium.org fhernqvist@chromium.org webrtc-audio-uma@google.com Device status received by TrackAudioRenderer when switching the output device. This is a specific case of Media.Audio.Render.OutputDeviceStatus histogram. olka@chromium.org fhrenqvist@chromium.org webrtc-audio-uma@google.com Device status received during WebRTCAudioRenderer initialization. This is a specific case of Media.Audio.Render.OutputDeviceStatus histogram. olka@chromium.org fhernqvist@chromium.org webrtc-audio-uma@google.com Device status received by WebRTCAudioRenderer when switching the output device. This is a specific case of Media.Audio.Render.OutputDeviceStatus histogram. henrika@chromium.org olka@chromium.org media-audio@chromium.org Measures the execution time of CoreAudioUtil::SharedModeInitialize. Recorded when Chrome attempts to initialize the audio stream between the client and the device in shared mode. This captures the synchronous time spent waiting for the Windows WASAPI driver to initialize a shared-mode audio endpoint. Note: Although this function is currently only used for output (render) streams, we intentionally omit "Output.Win" from the metric name to maintain a 1:1 mapping with the underlying C++ CoreAudioUtil method name. frederikh@google.com webrtc-audio-uma@google.com Tracks the success and failure outcomes of platform-specific audio {Direction} device enumerations (e.g., WASAPI, CoreAudio). Helps detect if OS errors are causing the browser to cache incomplete or empty device lists. Recorded when the browser requests the list of audio {Direction} devices from the OS (e.g. during enumerateDevices). olka@chromium.org saza@chromium.org webrtc-audio-uma@google.com Whether a glitch in the {Type} audio at the OS level was detected during the first 1000 OS callbacks of an active input/output stream. A glitch is detected if the OS skips providing/requesting any frames of audio, and is recorded when the stream ends, as long as the stream saw at least one OS callback. Reported on Windows and Mac. olka@chromium.org saza@chromium.org webrtc-audio-uma@google.com The number of glitches that were detected at the OS level while an audio {Type} stream was active. A glitch is detected if the OS skips providing/requesting any frames of audio. This value is aggregated over a period of 1000 OS callbacks (every 10 seconds for buffer size 10 ms) and is logged at the end of each collection interval. Not recorded for streams shorter than 1000 callbacks. Reported on Windows, Mac and ChromeOS. olka@chromium.org saza@chromium.org webrtc-audio-uma@google.com The length in milliseconds of the largest glitch that was detected at the OS level by an audio input {Type} stream. This value is aggregated over a period of 1000 OS callbacks (every 10 seconds for buffer size 10 ms) and is logged at the end of each collection interval if any glitches were detected. Not recorded for streams shorter than 1000 callbacks. Reported on Windows and Mac. olka@chromium.org saza@chromium.org webrtc-audio-uma@google.com The combined length in milliseconds of {Type} audio glitches detected at the OS level. This is useful to know in particular for audio processing such as echo cancellation. This value is aggregated over a period of 1000 OS callbacks (every 10 seconds for buffer size 10 ms) and is logged at the end of each collection interval if any glitches were detected. Not recorded for streams shorter than 1000 callbacks. Reported on Windows and Mac. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The duration of audio glitches occurring in the OS-specific implementation of an audio stream (AudioInputStream for Capture and Loopback, and AudioOutputStream for Render). Reported every time a glitch occurs. olka@chromium.org gustaf@chromium.org webrtc-audio-uma@google.com Whether there is input audio glitches due to dropped input audio data or not. Sampled when a low-latency input audio stream is destructed. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The number of input audio data blocks that were dropped at the browser/renderer boundary due to for example buffer overflow in the writer side buffer or in the socket. This value is aggregated over a period of 1000 input data pushes (every 10 seconds for buffer size 10 ms) and is logged at the end of each collection interval. Not recorded for streams with less than 1000 input data pushes. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The number of input audio data blocks that were dropped at the browser/renderer boundary due to for example buffer overflow in the writer side buffer or in the socket. This value is only logged for streams with less than 1000 input data pushes (10 seconds for buffer size 10 ms). fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The number of times input audio data blocks that had to be buffered because there was not room in the shared memory ring buffer on the browser/renderer boundary. This happens if the reading side hasn't read data in time. This value is aggregated over a period of 1000 input data pushes (every 10 seconds for buffer size 10 ms) and is logged at the end of each collection interval. Not recorded for streams with less than 1000 input data pushes. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The number of times input audio data blocks that had to be buffered because there was not room in the shared memory ring buffer on the browser/renderer boundary. This happens if the reading side hasn't read data in time. This value is only logged for streams with less than 1000 input data pushes (10 seconds for buffer size 10 ms). dalecurtis@chromium.org Audio codec used in HTML5 media. dalecurtis@chromium.org media-dev-uma@chromium.org Audio codec profile used in HTML5 media for AAC playback. iwells@chromium.org clank-readaloud@google.com Records connection status changes for {AudioDeviceType} audio devices, emitted when a device is connected or disconnected. Disconnection of Bluetooth devices may be reported more than fifteen seconds after the device is actually disconnected. If using a 3.5mm-to-USB adapter, a 3.5mm device may be reported as USB. steimel@chromium.org media-dev-uma@chromium.org Recorded when the AudioDuckerWin attempts to stop ducking other applications while at least 1 application is currently being ducked. Records `Failure` if we receive errors querying the OS for the list of audio sessions, otherwise records `Success`. steimel@chromium.org media-dev-uma@chromium.org Recorded when the AudioDuckerWin attempts to stop ducking another application. Records `Failure` if we receive errors from the OS when attempting to re-adjust the other application's volume, otherwise records `Success`. dalecurtis@chromium.org olka@chromium.org henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Measures the execution time of AudioInputController{MediaAudioInputControllerTime}. Recorded when the corresponding AudioInputController method finishes execution. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The audio capture delay in the Audio Service, including the IPC and the OS. Logged at every CaptureCallback::Capture() call at AudioInputDevice level. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The number of events causing audio capture glitches in the Audio Service, including the IPC and the OS. A glitch is when capture data is dropped due to a buffer overflow. Logged at the end of each 1000-callback interval for Intervals. Logged at the end of the stream for Short. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com The proportion of the audio capture interval that was dropped due to buffer overflows in the Audio Service, including the IPC and the OS. Logged at the end of each 1000-callback interval for Intervals. Logged at the end of the stream for Short. olka@chromium.org guidou@chromium.org webrtc-audio-uma@google.com A boolean that reflects whether or not an error was reported during audio rendering, reported after a stream has stopped, if it was started. olka@chromium.org guidou@chromium.org webrtc-audio-uma@google.com Time interval from the output stream controller construction to its destruction. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Whether an AudioOutputController succeeded in creating and opening an output stream proxy after receiving a default device change event. Note: in September 2021 this histogram unintentionally swapped its meaning with Media.AudioOutputController.ProxyStreamCreationResultForDeviceChange. guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Whether an AudioOutputController succeeded in creating and opening an output stream proxy. Only logged for the initial creation, subsequent re-creations due to device change events are logged in the Media.AudioOutputController.ProxyStreamCreationResult histogram. Note: in September 2021 this histogram unintentionally swapped its meaning with Media.AudioOutputController.ProxyStreamCreationResult. dalecurtis@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Time spent waiting in AudioOutputController::WaitTillDataReady() if the data was not initially available. dalecurtis@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Whether playback started successfully after stream startup was requested. olka@chromium.org henrika@chromium.org guidou@chromium.org webrtc-audio-uma@google.com Measures the execution time of AudioOutputController{MediaAudioOutputControllerTime}. Recorded when the corresponding AudioOutputController method finishes execution. fhernqvist@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com The audio playout delay in the Audio Service, including the IPC and the OS. Logged at every RenderCallback::Render() call at AudioPlayoutDevice level. fhernqvist@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com The number of events causing audio playout glitches in the Audio Service, including the IPC and the OS. A glitch is an inserted silence due to an underrun. Logged at the end of each 1000-callback interval for Intervals. Logged at the end of the stream for Short. fhernqvist@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com The proportion of the audio playout interval that was silent due to underruns in the Audio Service, including the IPC and the OS. Logged at the end of each 1000-callback interval for Intervals. Logged at the end of the stream for Short. olka@chromium.org armax@chromium.org guidou@chromium.org webrtc-audio-uma@google.com Whether a low latency stream to be rendered through the resampler was opened successfully or which type of fallback stream was used instead. In case a fake fallback stream is used it means audio rendered through the resampler will be muted. In case fallback fails entirely, renderer callback error will be signalled. In case audio output stream is opened in offload mode, record successful opening in offload mode explicitly to distinguish from non-offload mode. olka@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com Records format used by AudioManager to create audio output stream proxy. If a fake stream is created it results in muted audio playback. dalecurtis@chromium.org olka@chromium.org tguilbert@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Captures if render-side audio glitches are detected or not. Sampled when a low-latency output audio stream is destructed. olka@chromium.org fhernqvist@google.com webrtc-audio-uma@google.com Status of audio sink used by AudioRendererImpl. If not OK, a NullAudioSink will be used for audio output instead. This is logged for every call to AudioRendererImpl::Initialize, which generally occurs once per active audio session (i.e., between a play and pause). If audio track changes are ever enabled, it may additionally be called for every audio track change. fhernqvist@google.com olka@chromium.org dalecurtis@chromium.org tguilbert@chromium.org webrtc-audio-uma@google.com The number of SyncReader::Read() calls where the renderer missed its realtime deadline. Logged at the end of each 1000-read interval for Intervals. Logged at the end of the stream for Short. fhernqvist@google.com olka@chromium.org webrtc-audio-uma@google.com How long it take for the audio manager instance to be created by the audio service, in case the audio service owns the audio manager. toprice@chromium.org olka@chromium.org Records whether AudioSystemToServiceAdapter::GetDeviceDescriptions calls to the audio service returned successfully, or failed and retured an default empty list due to an audio service crash. dalecurtis@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com State of the audio thread. A value of "started" is emitted once the hang monitor has been initialized. If the thread is detected as hung later, a value of "hung" is emitted. If the hung thread later recovers a value of "recovered" is emitted. philyan@chromium.org media-dev-uma@chromium.org Records the time elapsed between the user hiding an auto-picture-in-picture window and the user returning to the original tab. This is only recorded when the user taps the "hide" button (a headphone icon) on the PiP window on Android, which keeps the audio playing in the background. The hide icon is only visible for auto-pip initialized pausable media. bkeen@google.com media-dev-uma@chromium.org Recorded for automatic picture in picture reason "{AutomaticReason}", when the user either selects an option from the Automatic picture-in-picture permission prompt, or when the user manually closes the picture-in-picture window without responding to the prompt, or when we decide to not show the prompt at all. When the prompt is shown, this records their selection (or "Ignored" if they did not select an option). When the prompt is not shown, records why it was not shown. bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time elapsed is recorded when the Picture in Picture window is closed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). bkeen@google.com media-dev-uma@chromium.org Total time spent accross all Picture in Picture windows opened by the `AutoPictureInPictureTabHelper`, for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time is accumulated any time the tab helper opens and subsequently closes a picture in picture window. The total picture in picture time is recorded when the `AutoPictureInPictureTabHelper` is destroyed. This metric does not differentiate between the Picture in Picture window types (document vs video). bkeen@google.com media-dev-uma@chromium.org Total time spent accross all Picture in Picture windows opened by the `AutoPictureInPictureTabHelper`, for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time is accumulated any time the tab helper opens and subsequently closes a picture in picture window. The total picture in picture time is recorded when the `AutoPictureInPictureTabHelper` is destroyed. This metric does not differentiate between the Picture in Picture window types (document vs video). Similar to Media.AutoPictureInPicture.EnterPictureInPicture.AutomaticReason.{AutomaticReason}.TotalTimeForSession, but with a maximum of 10 hours and a bucket size of 100. bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time elapsed is recorded when the Picture in Picture window is closed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). Similar to Media.AutoPictureInPicture.EnterPictureInPicture.AutomaticReason.{AutomaticReason}.TotalTime, but with a maximum of 10 hours and a bucket size of 100. philyan@google.com media-dev-uma@chromium.org Records the ratio of watch time (i.e., when the video was actively playing) to total time the Picture-in-Picture window was open, for windows opened automatically for the MediaPlayback reason. Recorded when the window is closed. This helps understand user engagement with auto-PiP windows. philyan@google.com media-dev-uma@chromium.org Records the cumulative watch time (i.e., when the video was actively playing) within a Picture-in-Picture window that was opened automatically for the MediaPlayback reason. Recorded when the window is closed. To understand the proportion of time spent watching video vs the total time the window was open, see `PlaybackToTotalTimeRatio`. bkeen@google.com media-dev-uma@chromium.org Recorded for automatic picture in picture reason "{AutomaticReason}", when the user either selects an option from the Automatic picture-in-picture permission prompt, or when the user manually closes the picture-in-picture window without responding to the prompt, or when we decide to not show the prompt at all. When the prompt is shown, this records their selection (or "Ignored" if they did not select an option). When the prompt is not shown, records why it was not shown. The AutomaticReasonV2 histograms add the BrowserInitiated bucket. bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time elapsed is recorded when the Picture in Picture window is closed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). The AutomaticReasonV2 histograms add the BrowserInitiated bucket. bkeen@google.com media-dev-uma@chromium.org Total time spent accross all Picture in Picture windows opened by the `AutoPictureInPictureTabHelper`, for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time is accumulated any time the tab helper opens and subsequently closes a picture in picture window. The total picture in picture time is recorded when the `AutoPictureInPictureTabHelper` is destroyed. This metric does not differentiate between the Picture in Picture window types (document vs video). The AutomaticReasonV2 histograms add the BrowserInitiated bucket. bkeen@google.com media-dev-uma@chromium.org Total time spent accross all Picture in Picture windows opened by the `AutoPictureInPictureTabHelper`, for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time is accumulated any time the tab helper opens and subsequently closes a picture in picture window. The total picture in picture time is recorded when the `AutoPictureInPictureTabHelper` is destroyed. This metric does not differentiate between the Picture in Picture window types (document vs video). Similar to Media.AutoPictureInPicture.EnterPictureInPicture.AutomaticReason.{AutomaticReason}.TotalTimeForSession, but with a maximum of 10 hours and a bucket size of 100. The AutomaticReasonV2 histograms add the BrowserInitiated bucket. bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window for automatic picture in picture reason "{AutomaticReason}". The timer starts counting every time the AutoPictureInPictureTabHelper calls `EnterAutoPictureInPicture`; the time elapsed is recorded when the Picture in Picture window is closed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). Similar to Media.AutoPictureInPicture.EnterPictureInPicture.AutomaticReason.{AutomaticReason}.TotalTime, but with a maximum of 10 hours and a bucket size of 100. The AutomaticReasonV2 histograms add the BrowserInitiated bucket. bkeen@google.com media-dev-uma@chromium.org Records the elapsed time from when an AutoPictureInPicture window opens to when the permission prompt result is recorded. Recorded once per PiP session when SetPromptResult is invoked. bkeen@google.com media-dev-uma@chromium.org Records the elapsed time from when an AutoPictureInPicture window opens to when a Happiness Tracking Survey launch is initiated. Recorded inside the success callback when the survey is launched. bkeen@google.com media-dev-uma@chromium.org Records whether an AutoPictureInPicture Happiness Tracking Survey launch was initiated or the reason why it was dropped. Recorded every time an AutoPictureInPicture window closes and survey eligibility is evaluated. steimel@chromium.org media-dev-uma@chromium.org Recorded when the user either selects an option from the Automatic picture-in-picture permission prompt, or when the user manually closes the picture-in-picture window without responding to the prompt, or when we decide to not show the prompt at all. When the prompt is shown, this records their selection (or "Ignored" if they did not select an option). When the prompt is not shown, records why it was not shown. thefrog@chromium.org chrome-counter-abuse-alerts@google.com Records the result of the Safe Browsing blocklist check for Auto Picture-in-Picture URL safety. Logged when the check completes or times out. philyan@chromium.org media-dev-uma@chromium.org Records whether an enterprise policy override allowed media autoplay. Recorded when media begins playing in a WebContents, based on the cached policy decision. philyan@chromium.org media-dev-uma@chromium.org Records the policy status that governed autoplay. Recorded when media begins playing in a WebContents, based on the cached policy decision. guidou@chromium.org tguilbert@chromium.org Usage of various BreakoutBox features. Recorded when a stream is created or transferred in MediaStreamTrackProcessor or MediaStreamTrackGenerator. chcunningham@chromium.org media-dev-uma@chromium.org Time spent between receiving a decodingInfo() call and resolving it. It only record successful calls and ignores audio-only. chcunningham@chromium.org media-dev-uma@chromium.org Time spent between receiving a decodingInfo() call and resolving it. It only record successful calls and ignores audio-only. This is a subset of Media.Capabilities.DecodingInfo.RequestTime.Video that only takes into account clear content. chcunningham@chromium.org media-dev-uma@chromium.org Time spent between receiving a decodingInfo() call and resolving it. It only record successful calls and ignores audio-only. This is a subset of Media.Capabilities.DecodingInfo.RequestTime.Video that only takes into account encrypted content. kron@chromium.org media-dev-uma@chromium.org Records whether an asynchronous MediaCapabilities {QueryType} query timed out (true) or completed and resolved before timing out (false). Recorded just before the query promise is resolved, either upon normal completion with capabilities or upon timing out with fallback capabilities. vasilyt@chromium.org media-dev-uma@chromium.org Records if the guessed coded size and/or MediaFormat.KEY_WIDTH/MediaFormat.KEY_HEIGHT were correct. Recorded once per resolution change (including the first frame). jophba@chromium.org media-dev-uma@chromium.org Records whether creating an AudioFileReader for processing WebAudio was successful. jophba@chromium.org media-dev-uma@chromium.org Records the average amount of time per frame required to decode an audio file provided to the WebAudio API. jophba@chromium.org media-dev-uma@chromium.org Records the file duration calculated during decoding an audio file provided to the WebAudio API. steimel@chromium.org media-dev-uma@chromium.org Records events related to click through rate (CTR) calculation. The CTR can be calculated by computing "Interacted" / "Displayed". "Interacted", for buttons, means that they were clicked. For sliders, it will reflect any change in the internal state and includes other events in addition to clicks. "Displayed" means that the control element was meant to be displayed in the controls. It does not mean that the user have seen the element so is not to be confused with visibility. Furthermore, because the controls UI changes while loading, "Displayed" is only computed when metadata are available unless preloading was disabled on the element or the browser. Data is missing from 2020-04-05 to 2021-05-18. {MediaControlsElements} yrw@chromium.org media-dev-uma@chromium.org Record each time user pins/unpins CrOS global media controls. Warning: this histogram was expired from 2022-04-24 to 2024-01-04; data may be missing. yrw@chromium.org media-dev-uma@chromium.org Record each time media controls' sub-menu in quick settings is opened. True if it is a repeat usage. Warning: this histogram was expired from 2022-05-01 to 2024-01-04; data may be missing. yrw@chromium.org media-dev-uma@chromium.org Record each time global media controls on the shelf is opened. True if it is a repeat usage. Warning: this histogram was expired from 2022-04-24 to 2024-01-04; data may be missing. liberato@chromium.org tmathmeyer@chromium.org This histogram lets us count how many PictureBuffers we've overallocated when we're allocating each texture separately. This case is relatively simple to optimize compared to SingleTexture. liberato@chromium.org tmathmeyer@chromium.org This histogram lets us count how many PictureBuffers we've overallocated when we're allocating in contiguous blocks. This case is harder to optimize than the MultiTexture variant, but it is good to know the proportion of the two of them to determine usage. dalecurtis@chromium.org media-dev-uma@chromium.org Audio codec used in HTML5 media. Reporting corrected in M51 to include all detected audio codecs, not just those up to and including the first one supported. dalecurtis@chromium.org media-dev-uma@chromium.org Audio codec used in HTML5 media for a local file playback. dalecurtis@chromium.org media-dev-uma@chromium.org Container used for HTML5 media. Views that include pre-M34 data will categorize dash (38) and smooth streaming (39) in the "Other" bucket. dalecurtis@chromium.org media-dev-uma@chromium.org Container used for HTML5 media for a local file playback. dalecurtis@chromium.org media-dev-uma@chromium.org Video codec used in HTML5 media. Reporting corrected in M51 to include all detected video codecs, not just those up to and including the first one supported. dalecurtis@chromium.org media-dev-uma@chromium.org Video codec used in HTML5 media for a local file playback. steimel@chromium.org liberato@chromium.org media-dev-uma@chromium.org Records the reason why a document picture-in-picture window is closed (e.g. the user clicking on the Back to Tab button). Recorded on destruction of the picture-in-picture window. steimel@chromium.org liberato@chromium.org media-dev-uma@chromium.org Records the height that the website has requested for a document picture-in-picture window. Recorded when calculating the initial bounds of a newly-opened document picture-in-picture window. steimel@chromium.org liberato@chromium.org media-dev-uma@chromium.org Records the width that the website has requested for a document picture-in-picture window. Recorded when calculating the initial bounds of a newly-opened document picture-in-picture window. If the website requests a size larger than the area of the screen, it will be recorded as 100%. If a website does not request a size or requests a size of zero, it is recorded as 1%. steimel@chromium.org media-dev-uma@chromium.org Recorded when a website opens a document picture-in-picture window. Records `Occurred` if the website requested a window size larger than the maximum allowed window size, otherwise records `Did not occur`. steimel@chromium.org media-dev-uma@chromium.org Recorded when a website resizes a document picture-in-picture window via the `resizeTo()` or `resizeBy()` APIs. Records `Occurred` if the website requested a window size larger than the maximum allowed window size, otherwise records `Did not occur`. steimel@chromium.org liberato@chromium.org media-dev-uma@chromium.org Records the ratio of the total screen area that the website has requested for the picture-in-picture window, specifically the requested width times the requested height as a ratio of the screen's width times height. Recorded when calculating the initial bounds of a newly-opened document picture-in-picture window. dalecurtis@chromium.org media-dev-uma@chromium.org Count of dropped frames between pipeline start and stop. Media pipeline starts/stops when an HTML5 video is loaded/unloaded respectively in the browser. dalecurtis@chromium.org frankli@microsoft.com media-dev-uma@chromium.org Monitors the DroppedFrameCount that is originated from a {RendererType} and the video playback is {ClearOrEncrypted}. It is the count of dropped video frames when an HTML5 video is unloaded. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Tracks the result of calls to RestrictionTarget.fromElement(). Specifically, this histogram tracks whether a new Promise was produced, and if not, why not. Another histogram tracks the result of new Promises, i.e. whether they were resolved or rejected. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org When RestrictionTarget.fromElement() is called for the first time on a given Element, a new Promise is produced. This histogram tracks the result of this Promise - whether it was resolved or rejected. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Duration in milliseconds of the time it takes for a BrowserCaptureMediaStreamTrack.restrictTo() call to resolve (either successfully or with an error). Note a call which never resolves won't be counted in this metric. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Tracks the result of calls to BrowserCaptureMediaStreamTrack.restrictTo(). Recorded when resolving the promise produced by restrictTo(). Warning: this histogram was expired from 2024-09-20 to 2025-03-25; data may be missing. xhwang@chromium.org media-dev-uma@chromium.org Size in KB of the last file successfully read by the CDM through CDM FileIO before a specific error happens. This is reported only when the error happens, which should be rare. xhwang@chromium.org media-dev-uma@chromium.org Size in KB of the first file successfully read by the CDM through CDM FileIO. This is recorded once per CDM instance. sangbaekpark@chromium.org media-dev-uma@chromium.org The actual time spent by the CDM FileIO {FileOperation} operation under {IncognitoOrNormal} mode. Only recorded for successful operations. vpasupathy@chromium.org media-dev-uma@chromium.org Size in KB of a file written by the CDM through CDM FileIO. This is recorded once per write through the CDM. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether a CDM FileIO {FileOperation} operation succeded or not under {IncognitoOrNormal} mode. xhwang@chromium.org media-dev-uma@chromium.org The status of file open received by MojoCdmFileIO. This is reported every time the CDM tries to open a file for read or write. xhwang@chromium.org media-dev-uma@chromium.org The status of CDM host verification. This is reported per CDM load. xhwang@chromium.org media-dev-uma@chromium.org Chromium could support multiple versions of CDM interface. This metric records the CDM interface version that the CDM created by Chromium uses. This is recorded once per CDM instance. xhwang@chromium.org media-dev-uma@chromium.org The error code of a library CDM load failure. Only reported on Windows. xhwang@chromium.org media-dev-uma@chromium.org The result from an attempt to load a library CDM. xhwang@chromium.org media-dev-uma@chromium.org The time spent to load a library CDM. vpasupathy@chromium.org media-dev-uma@chromium.org Counts every time a debugger is attached to a CDM utility process. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA records when the CdmStorageDatabase for a profile is incompatible. This UMA is recorded on every OpenDatabase call that detects the database with a version number of one, which means that it is operating under a schema that does not include file_size and last_modified. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA records when the data being written to the CdmStorageDatabase exceeds 15 KB. This UMA is recorded on every write over 15KB that succeeds. vpasupathy@chromium.org media-dev-uma@chromium.org SQLite specific errors reported while using the Cdm Storage Database. Recorded on any error from a database operation. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA records SQLite specific errors that occur when executing the operation {CdmDatabaseOperation}. This UMA is recorded on every error for this operation. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA records the errno that occur when executing the operation {CdmDatabaseOperation} and getting a specific {SqliteError}. This UMA is recorded every time this operation errors with the specific {SqliteError}. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA records the current CdmStorageDatabase size in KB. This UMA is recorded only once, on the first read, to retrieve usage levels of the CdmStorageDatabase. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from opening the CdmStorageDatabase. Recorded on every open. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from opening the CdmStorageDatabase. Recorded on every open from an {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the DeleteFile function. Recorded after every call of DeleteFile on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the DeleteForStorageKey function. Recorded after every call of DeleteForStorageKey on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the DeleteForTimeFrame function. Recorded after every call of DeleteForTimeFrame on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the GetSizeForFile function. Recorded after every call of GetSizeForFile on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the GetSizeForStorageKey function. Recorded after every call of GetSizeForStorageKey on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the GetSizeForTimeFrame function. Recorded after every call of GetSizeForTimeFrame on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the DeleteForFilter function. Recorded after every call of DeleteForFilter on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the ReadFile function. Recorded after every call of ReadFile on {ProfileType} profile. vpasupathy@chromium.org media-dev-uma@chromium.org This UMA logs overall error rates from the WriteFile function. Recorded after every call of WriteFile on {ProfileType} profile. sangbaekpark@chromium.org media-dev-uma@chromium.org Outcome of attempting to create a browser-owned content-protection HWND (used by Media Foundation hardware DRM to pick the correct GPU adapter on multi-GPU systems). hiroh@chromium.org cros-gfx-video@google.com Whether we used the platform CDM on Chrome OS that includes HW secure Widevine support, or fell back to the Chrome SW CDM. Warning: this histogram was expired from 2024-05-19 to 2025-09-01; data may be missing. hiroh@chromium.org cros-gfx-video@google.com System code in promise rejection for ChromeOS platform CDM. Warning: this histogram was expired from 2024-01-05 to 2025-09-01; data may be missing. sangbaekpark@chromium.org media-dev-uma@chromium.org Ratio of the number of decorder bypass blocks seen / total frames displayed * 100. Recorded for each video that could contain decoder bypass blocks. xhwang@chromium.org media-dev-uma@chromium.org Whether EME encrypted event has been fired. Every time a WebMediaPlayerImpl object is created a "false" value is reported to provide a baseline. Every time an encrypted event is fired, a "true" value will be reported. Note that it is possible to have multiple encrypted events during the lifetime of a WebMediaPlayerImpl object. xhwang@chromium.org media-dev-uma@chromium.org Whether encrypted media is enabled when requestMediaKeySystemAccess() is called. User can enable and disable encrypted media in content settings. Recorded when requestMediaKeySystemAccess() is called but will be reported at most once per renderer process. sangbaekpark@chromium.org media-dev-uma@chromium.org The encryption scheme used by the audio stream in an HTML5 video. Reported when metadata is available if the initial config is encrypted. sangbaekpark@chromium.org media-dev-uma@chromium.org The encryption scheme used by the video stream in an HTML5 video. Reported when metadata is available if the initial config is encrypted. feras@chromium.org media-dev-uma@chromium.org Whether Media Foundation based CDM is enabled or disabled based on previous disabled timestamps in a "User Profile" pref. This is reported once per browsing session when user requests hardware secure playback if Media Foundation based CDM is enabled and available. xhwang@chromium.org media-dev-uma@chromium.org Whether a given WebMediaPlayer instance, with a CDM attached, is played in an incognito window or in Chrome OS guest mode. Players that never started playback are excluded. Recorded once at time of player destruction. xhwang@chromium.org media-dev-uma@chromium.org Whether MediaCrypto is available on a MediaDrm-based CDM. Reported once per MediaDrmBridge creation. In normal cases it should always be available. vpasupathy@chromium.org media-dev-uma@chromium.org The Android Api level the device was released with, retrieved by obtaining |ro.product.first_api_level| from the OS. We record this once at time of checking the FirstApiLevel during the pre-provisioning flow. sangbaekpark@chromium.org media-dev-uma@chromium.org The status of every attempt to obtain a pre-provisioned origin ID to be used by MediaDrm. This will only be reported for applications that use MediaDrmOriginIdManager. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of pre-provisioned origin IDs available shortly after startup on devices that do not support per-application provisioning. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of pre-provisioned origin IDs available shortly after startup on devices that support per-application provisioning. sangbaekpark@chromium.org media-dev-uma@chromium.org Result of trying to provision an origin using MediaDrm. Called every time provisioning is attempted, once per origin. vpasupathy@chromium.org media-dev-uma@chromium.org Result of a network connection change event triggering a retry attempt for background preprovisioning of MediaDrm origin IDs. This records whether the event was ignored due to exponential backoff or if a retry was actually attempted. xhwang@chromium.org media-dev-uma@chromium.org Whether MediaDrmBridge supports the key system. Reported once per MediaDrmBridge creation. In normal cases it should always be supported. sangbaekpark@chromium.org media-dev-uma@chromium.org HRESULT of MediaFoundationCdmModule::ActivateCdmFactory(). This is only reported when ActivateCdmFactory() fails. sangbaekpark@chromium.org media-dev-uma@chromium.org The error code of a library CDM load failure. Only reported on Windows. sangbaekpark@chromium.org media-dev-uma@chromium.org The result from an attempt to load a library MediaFoundation CDM. sangbaekpark@chromium.org media-dev-uma@chromium.org The time spent to load a library MediaFoundation CDM. xhwang@chromium.org media-dev-uma@chromium.org HRESULT of the first (and only the first) MediaFoundationCdm initialization in a MediaFoundationService process when using {KeySystem} in hardware secure mode. Reported on both successes and failures. vpasupathy@chromium.org media-dev-uma@chromium.org HRESULT of MediaFoundationCdm initialization when using {KeySystem} in hardware secure mode. Only reported on failures. sangbaekpark@chromium.org media-dev-uma@chromium.org HRESULT of setting the content protection window for GPU adapter selection when using {KeySystem} in hardware secure mode. Reported on both successes and failures. xhwang@chromium.org media-dev-uma@chromium.org HRESULT of MediaFoundationCdm and MediaFoundationCdmSession operations when using {KeySystem} in hardware secure mode. xhwang@chromium.org media-dev-uma@chromium.org Whether a MediaFoundationService process crash is within 5 seconds after power or display change. Reported when the MediaFoundationService process crashes. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether Dolby Vision codec with HDR check is supported or not. When multiple displays are connected to the device, TRUE if the primary display (internal) is HDR/HDR. Reported once per browser session lifetime. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether Dolby Vision codec without HDR check is supported or not. Reported once per browser session lifetime. xhwang@chromium.org media-dev-uma@chromium.org HRESULTs associated with errors happened in the MediaFoundationService process within 5 seconds after power or display change. xhwang@chromium.org media-dev-uma@chromium.org HRESULTs associated with errors happened in the MediaFoundationService process NOT within 2 seconds after power or display change. xhwang@chromium.org media-dev-uma@chromium.org Whether a HardwareContextReset event happened in the MediaFoundationService process within 5 seconds after power or display change. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU's display information whether likely built-in or external when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active and non-active GPU vendor information when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU vendor ID when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of displays when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not the active GPU matches with the display GPU on multi-GPU devices when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of GPUs when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has NVIDIA active GPU associated with an external displays when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has an active GPU associated with an external displays when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Non-active GPU vendor ID when a HardwareContextReset event happened in the MediaFoundationService process. Reported whenever such an event happens. xhwang@chromium.org media-dev-uma@chromium.org Time for MediaFoundationService.IsKeySystemSupported() to finish. Reported once per browser session lifetime. vpasupathy@chromium.org media-dev-uma@chromium.org The time spent to get CdmCapability for {KeySystem}. The value will be reported once per CDM instance for hw security in MediaFoundationService. This value will only be reported for successful retrievals of the CDM Capability. vpasupathy@chromium.org media-dev-uma@chromium.org Time for IMFExtendedDRMTypeSupport::IsTypeSupportedEx() to finish in MediaFoundationService when using {KeySystem} in hardware secure mode, which are called by MediaFoundationService.IsKeySystemSupported() (called once per CDM per browser session lifetime). IsKeySystemSupported() calls IsTypeSupportedEx() multiple times, for different audio/video codecs and encryption schemes. xhwang@chromium.org media-dev-uma@chromium.org Whether connection error has happened for MojoCdm. Every time a MojoCdm object is created a "false" value is reported to provide a baseline. Every time a mojo connection error happened, a "true" value will be reported, which typically means a remote CDM process crash. xhwang@chromium.org media-dev-uma@chromium.org Output protection query status and result. One query and one positive (no unprotected external links) result (if any) are reported per CDM instance. hiroh@chromium.org cros-gfx-video@google.com Output protection query status and result. One query and one positive (no unprotected external links) result (if any) are reported per CDM instance. Warning: this histogram was expired from 2022-01-05 to 2025-09-01; data may be missing. xhwang@chromium.org media-dev-uma@chromium.org {KeySystem} support query status and result, as reported by RequestMediaKeySystemAccess. Each value will be reported at most once per frame. vpasupathy@chromium.org media-dev-uma@chromium.org The time spent to reject RequestMediaKeySystemAccess() for {KeySystem}. Each time will be reported at most once per process. Only one of TimeTo.Resolve or TimeTo.Reject will be reported at most once per process for a {KeySystem}. vpasupathy@chromium.org media-dev-uma@chromium.org The time spent to resolve RequestMediaKeySystemAccess() for {KeySystem}. Each time will be reported at most once per process. Only one of TimeTo.Resolve or TimeTo.Reject will be reported at most once per process for a {KeySystem}. sangbaekpark@chromium.org media-dev-uma@chromium.org The net error or HTTP response code of provisioning requests made by UrlProvisionFetcher on Android and Cast devices. xhwang@chromium.org media-dev-uma@chromium.org Whether the CDM is available for Widevine or not. In normal cases, this is reported once per render process if the EME API is used. In rare cases it could be reported more than once if the CDM is not available and then is component updated. xhwang@chromium.org media-dev-uma@chromium.org System code in promise rejection when using Widevine key system in software secure mode. xhwang@chromium.org media-dev-uma@chromium.org Whether the robustness level of any video capability in the supported configuration passed into requestMediaKeySystemAccess() is empty. This is specific to the Widevine key system. sangbaekpark@chromium.org media-dev-uma@chromium.org HRESULT code if CreateDummyMediaFoundationCdm call fails when querying hardware secure CDM capability. sangbaekpark@chromium.org media-dev-uma@chromium.org HRESULT code if MediaFoundationCdmModule::GetCdmFactory call fails when querying {KeySystem} CDM capability. xhwang@chromium.org media-dev-uma@chromium.org Whether the CDM instance is created successfully for {KeySystem}. Reported each time a CDM instance creation is attempted, usually as a result of Javascript call of createMediaKeys(). sangbaekpark@chromium.org media-dev-uma@chromium.org The status when creating a CDM instance for {KeySystem}. Reported each time a CDM instance creation is attempted, usually as a result of Javascript call of createMediaKeys(). xhwang@chromium.org media-dev-uma@chromium.org Time took to create the CDM instance for {KeySystem}. xhwang@chromium.org media-dev-uma@chromium.org EME session type passed into CreateSession. xhwang@chromium.org media-dev-uma@chromium.org The timeout status of MojoCdm::CreateSessionAndGenerateRequest() call. sangbaekpark@chromium.org media-dev-uma@chromium.org The status of the CDM capability query. This can be used to inspect the reason when no capability reported. Reported at most once per browser session per key system when EME query is triggered by a website. xhwang@chromium.org media-dev-uma@chromium.org The CdmInfo::Status of {KeySystem} hardware secure CDM capability. Reported at most once per browser session when EME query is triggered by a website. xhwang@chromium.org media-dev-uma@chromium.org When hardware secure decryption is enabled, whether {KeySystem} hardware secure decryption is actually supported by the platform (device). Reported at most once per browser session when EME query is triggered by a website, and when {KeySystem} hardware secure CDM was registered. xhwang@chromium.org media-dev-uma@chromium.org When hardware secure decryption is enabled and supported by {KeySystem}, whether {VideoCodec} video codec is supported by the platform (device). Reported at most once per browser session when EME query is triggered by a website, and when {KeySystem} hardware secure CDM was registered. xhwang@chromium.org media-dev-uma@chromium.org Reports a summary of key statuses associated with an EME CDM session. Reported once per EME CDM session on the first key statuses update. xhwang@chromium.org media-dev-uma@chromium.org System code associated with key status for {KeySystem}. sangbaekpark@chromium.org media-dev-uma@chromium.org Reports a summary of key statuses associated with an EME CDM session. Reported once per EME CDM session on the last key statuses update when the EME CDM session gest closed. xhwang@chromium.org media-dev-uma@chromium.org The time it takes to {ResolveOrReject} a EME promise. xhwang@chromium.org media-dev-uma@chromium.org Reports whether a playback with a CDM attached has been blocked waiting for the CDM to be set or waiting for decryption key. Reported once per playback when a CDM attached. xhwang@chromium.org media-dev-uma@chromium.org Result of EME promises that were handled by Chromium code. xhwang@chromium.org media-dev-uma@chromium.org System code in promise rejection. dalecurtis@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Whether Chrome had to fallback to the high latency audio path or not. The fallback might be from either low latency offload path, or from low latency non-offload path. dalecurtis@chromium.org media-dev-uma@chromium.org Indicates if the guessed coded size would have matched the real coded size. Recorded on acquisition of real coded size for the first frame of playback. dalecurtis@chromium.org frankli@microsoft.com media-dev-uma@chromium.org Monitors the number of video frames being read back from a {RendererType}. It is the count of video frames being read back from an HTML5 video when it is unloaded. philyan@google.com media-dev-uma@chromium.org The duration of a fullscreen video Picture-in-Picture session on Android. Recorded when the PiP session is exited (e.g., when Chrome switches back to non-PiP mode or when the PiP window is directly closed). philyan@google.com media-dev-uma@chromium.org Recorded when Chrome attempts to enter Picture-in-Picture mode for a fullscreen video on Android. Logs `Entered` if PiP is successfully set up. Logs `Failed - No WebContents` if the tab is closing. Logs `Failed - No ActivityTab` if the activity has no active tab. philyan@google.com media-dev-uma@chromium.org The reason why a fullscreen video Picture-in-Picture session ended on Android. Recorded when the PiP session is exited. brandstrom@chromium.org webrtc-audio-uma@google.com Records the result of trying to get the audio capture ID of an application whose window was selected in the getDisplayMedia() media picker on macOS. This is recorded once for each call to GetApplicationAudioCaptureIdForProcess(). kron@chromium.org olka@chromium.org gabrielbrito@microsoft.com Records the result of trying to get the application ID of an application whose window was selected in the getDisplayMedia() media picker on Windows. agpalak@chromium.org tovep@chromium.org rtc-meet-in-chrome@google.com Records whether getDisplayMedia was called with the audioSelection constraint. eladalon@chromium.org fbeaufort@chromium.org Records whether getDisplayMedia was called with the displaySurface constraint. eladalon@chromium.org fbeaufort@chromium.org Records whether getDisplayMedia was called with the monitorTypeSurfaces constraint. brandstrom@chromium.org webrtc-audio-uma@google.com Records whether getDisplayMedia was called with the RestrictOwnAudio constraint. eladalon@chromium.org fbeaufort@chromium.org Records whether getDisplayMedia was called with the selfBrowserSurface constraint. eladalon@chromium.org fbeaufort@chromium.org webrtc-audio-uma@google.com Records whether getDisplayMedia was called with the suppressLocalAudioPlayback constraint. eladalon@chromium.org fbeaufort@chromium.org Records whether getDisplayMedia was called with the surfaceSwitching constraint. eladalon@chromium.org fbeaufort@chromium.org webrtc-audio-uma@google.com Records whether getDisplayMedia was called with the systemAudio constraint. brandstrom@chromium.org kron@chromium.org webrtc-audio-uma@google.com Records whether getDisplayMedia was called with the windowAudio constraint. eladalon@chromium.org fbeaufort@chromium.org hendrich@chromium.org Records whether getDisplayMedia was called with a user gesture (transient activation) or whether it wasn't required. The requirement is only enforced once `blink::features::kGetDisplayMediaRequiresUserActivation` is enabled and can be bypassed with the `ScreenCaptureWithoutGestureAllowedForOrigins` policy. steimel@chromium.org media-dev-uma@chromium.org Records if the Global Media Controls device selector was available. Recorded once per notification either when the device selector was shown or when the notification disappears. steimel@chromium.org media-dev-uma@chromium.org Records if the Global Media Controls device selector was opened. Recorded once per notification either when the device selector was opened or when the notification disappears. This histogram is only recorded if the device selector was available. steimel@chromium.org media-dev-uma@chromium.org Recorded each time a media session is dismissed or removed from the Global Media Controls. Records the reason why it happened (e.g. user clicked the dismiss button or playback stopped). jophba@chromium.org openscreen-eng@google.com media-dev-uma@chromium.org Records the entry point whenever the user opens the Global Media Controls UI. steimel@chromium.org media-dev-uma@chromium.org Recorded each time a paused media session is interacted with (e.g. playing the media or clicking on the notification to go back to the tab). Records the time passed since it was last interacted with (or since when it was paused if this is the first post-pause interaction). jophba@chromium.org openscreen-eng@google.com Records the type of Media Route that users {Action} from the Global Media Controls dialog. Recorded when users click on a button and this histogram doesn't represent the actual number of sessions {Action}ed from the GMC dialog. yrw@chromium.org media-dev-uma@chromium.org Recorded when a user action is performed on the updated media item UI view in the media dialog view on non-CrOS desktop platforms. steimel@chromium.org media-dev-uma@chromium.org Recorded each time the Global Media Controls Device picker dialog is opened and is populated with devices. Records the number of device options displayed, possibly including the default fallback device. steimel@chromium.org media-dev-uma@chromium.org Recorded each time the Global Media Controls dialog is opened. True if this was repeat usage of the dialog (e.g. if it's not the first time the dialog has been opened this session). Note: This histogram was expired from 2026-01-18 to 2026-08-04; data may be missing. steimel@chromium.org media-dev-uma@chromium.org The focused state of the WebContents associated with the MediaSession that the user is interacting with via the Global Media Controls. Recorded when the user presses an action on the Global Media Controls dialog (e.g. play). Note: This histogram was expired from 2026-01-18 to 2026-08-04; data may be missing. hitawala@chromium.org shared-image-team@google.com Records whether Zero Copy import of SharedImage backed by GpuMemoryBuffer handle into WebGPU is supported. Result is an enum for support which is recorded once per VideoFrame creation. hitawala@chromium.org vasilyt@chromium.org shared-image-team@google.com Records the format used for creating video frames with hardware backed GpuMemoryBuffers. Result is an enum that represents OutputFormat in MappableSharedImageVideoFramePool. Recorded once per VideoFrame creation. hitawala@chromium.org vasilyt@chromium.org shared-image-team@google.com Records the format used for creating video frames with software backed GpuMemoryBuffers. Result is an enum that represents OutputFormat in MappableSharedImageVideoFramePool. Recorded once per VideoFrame creation. andrescj@chromium.org chromeos-gfx-video@google.com Counts the unsuccessful calls to GpuArcVideoDecodeAccelerator::Initialize() per VideoCodecProfile. Warning: this histogram was expired from 2025-01-05 to 2025-09-01; data may be missing. andrescj@chromium.org chromeos-gfx-video@google.com Counts the successful calls to GpuArcVideoDecodeAccelerator::Initialize() per VideoCodecProfile. Warning: this histogram was expired from 2025-01-05 to 2025-09-01; data may be missing. andrescj@chromium.org chromeos-gfx-video@google.com Counts how many GpuArcVideoDecodeAccelerator instances are alive at the time a new GpuArcVideoDecodeAccelerator is created. Warning: this histogram was expired from 2023-01-22 to 2023-06-21; data may be missing. Warning: this histogram was expired from 2024-06-22 to 2025-09-01; data may be missing. andrescj@chromium.org chromeos-gfx-video@google.com Counts how many GpuArcVideoDecodeAccelerator instances that have gone through initialization (i.e., have an underlying media::VideoDecodeAccelerator) are alive at the time a GpuArcVideoDecodeAccelerator goes through initialization and successfully creates its underlying media::VideoDecodeAccelerator. Warning: this histogram was expired from 2023-01-22 to 2023-06-21; 2024-06-22 to 2025-09-01; data may be missing. dalecurtis@chromium.org webrtc-audio-uma@google.com Channel count of the hardware audio device. dalecurtis@chromium.org webrtc-audio-uma@google.com Channel layout of the hardware audio device. dalecurtis@chromium.org webrtc-audio-uma@google.com Samples per second of the hardware audio device. steimel@chromium.org media-dev-uma@chromium.org Records media key presses that are handled by the HardwareKeyMediaController. Warning: this histogram was expired from 2021-08-29 to 2023-10-24; data may be missing. dalecurtis@chromium.org media-dev-uma@chromium.org Tracks accelerated video decoding support for a given codec. Recorded once per GPU process after an attempt to use accelerated video decoding. dalecurtis@chromium.org media-dev-uma@chromium.org Whether a given WebMediaPlayer instance, after preload, started playback; recorded once at time of player destruction. tmathmeyer@chromium.org media-dev-uma@chromium.org Logs any error which occurs during initialization of the hls demuxer. tmathmeyer@chromium.org media-dev-uma@chromium.org Logs any error which is caused by manifest parsing during either demuxer initialization or mid-playback. tmathmeyer@chromium.org media-dev-uma@chromium.org Logs any error which occurs during playback but NOT during initialization of the hls demuxer. xhwang@chromium.org media-dev-uma@chromium.org The timeout status of Renderer initialization. olka@chromium.org fhernqvist@google.com henrika@hromium.org webrtc-audio-uma@google.com Error codes that we encounter while setting up an AUAudioInputStream on Mac. henrika@chromium.org media-dev-uma@chromium.org webrtc-audio-uma@google.com Duration in milliseconds of low-latency audio input streams. Sampled when the stream is closed by the AudioInputController. olka@chromium.org henrika@chromium.org webrtc-audio-uma@google.com Duration in milliseconds of low-latency audio input streams which never got any callbacks. Warning: this histogram was expired from 2020-10-11 to 2021-06-04; data may be missing. xhwang@chromium.org media-dev-uma@chromium.org Load type of HTML5 media, such as URL, MediaSource and MediaStream. armax@chromium.org guidou@chromium.org olka@chromium.org Whether capture started successfully after a low-latency input stream startup was requested. magchen@chromium.org cros-gfx-video@google.com MappableSharedImageVideoFramePool is called with an unsupported VideoFrame pixel format. Emitted on VideoFrame arrival. dalecurtis@chromium.org The total watch time (see Media.WatchTime) of a given playback divided by the number of rebuffering events that occured during that playback. Only reported when rebuffering happened. Therefore, alway refer to other UMAs like `Media.RebuffersCount` when checking this UMA. {MediaRebufferingCategories} hscham@chromium.org lokeric@chromium.org openscreen-eng@google.com Records the reason why the media capture picker failed to be shown. Recorded each time the picker fails to show. hscham@chromium.org lokeric@chromium.org openscreen-eng@google.com Records the result of a user's interaction with the media capture picker. Recorded each time the picker is closed. vpasupathy@chromium.org media-dev-uma@chromium.org Negative error code from a CodecException reported by MediaCodec. Reported whenever MediaCodec returns a CodecException, and the CodecException is unknown and a negative value. sangbaekpark@chromium.org media-dev-uma@chromium.org Error reported by MediaCodec video streams using codec {VideoCodec} with {Secure}. Reported at most once per playback if an error occurs. guidou@chromium.org agpalak@chromium.org Tracks the state of the first enumerateDevices call in relation to the first successful getUserMedia call. Recorded on execution context destruction only if there was at least one enumerateDevices call. guidou@chromium.org agpalak@chromium.org Recorded when the first enumerateDevices call and/or the first successful getUserMedia call are resolved. The members of the histogram are not mutually exclusive. toprice@chromium.org agpalak@chromium.org The latency of calls to the navigator.mediaDevices.enumerateDevices() API which resolve, including both successes and failures. Note very long calls which record a EnumerateDevices.Result of kTimedOut but do eventually resolve will have their latency recorded. toprice@chromium.org agpalak@chromium.org The results of all calls to the navigator.mediaDevices.enumerateDevices() API, including successful promise resolutions, error codes, or kTimedOut, if the promise was still pending after 4 seconds. agpalak@chromium.org olka@chromium.org rtc-meet-in-chrome@google.com Records whether the device name matched when searching for an existing opened device during the processing of getUserMedia request. The search is done so that a device is opened only once per render frame. Logged for every device that matches the requested ID and type. True means the names matched, False means they differed. simonha@google.com video-cmi-apis@google.com The results of all calls to the navigator.mediaDevices.GetAllScreensMedia() API, including successful promise resolutions, error codes, or kTimedOut, if the promise was still pending after 6 seconds. The suffix 3 was added at milestone 145, after distribution of UserMediaRequestResult was changed. The histogram was expired from 2023-05-01 to 2026-01-12. kron@chromium.org video-cmi-apis@google.com Tracks the number of attempts to start an audio track from getDisplayMedia that results in PermissionDeniedBySystem. This is recorded in UserMediaProcessor::RequestInfo::OnTrackStarted when the result of the attempt to start the track is availble. toprice@chromium.org agpalak@chromium.org rtc-meet-in-chrome@google.com The latency of calls to the navigator.mediaDevices.GetDisplayMedia() API which resolve, including both successes and failures. Note very long calls which record a GetDisplayMedia.Result of kTimedOut but do eventually resolve will have their latency recorded. The suffix 2 was added in milestone 143, after the kTimedOut interval was increased from 12s to 30s. toprice@chromium.org agpalak@chromium.org video-cmi-apis@google.com The results of all calls to the navigator.mediaDevices.GetDisplayMedia() API, including successful promise resolutions, error codes, or kTimedOut, if the promise was still pending after 30 seconds. The suffix 3 was added at milestone 145, after distribution of UserMediaRequestResult was changed. hbos@chromium.org video-cmi-mpp@google.com When getUserMedia() is called for video, the capture resolution capabilities of the devices (webcams) are logged, including if HD/FullHD devices support 360p, 480p, neither or both. henrika@chromium.org guidou@chromium.org video-cmi-apis@google.com When getUserMedia() is called for audio, the utilized echoCancellationMode is logged. The mode controls how much of the user system playout is removed from the microphone signal. toprice@chromium.org agpalak@chromium.org video-cmi-apis@google.com The latency of calls to the navigator.mediaDevices.GetUserMedia() API which resolve, including both successes and failures. Note very long calls which record a GetUserMedia.Result of kTimedOut but do eventually resolve will have their latency recorded. toprice@chromium.org agpalak@chromium.org video-cmi-apis@google.com The results of all calls to the navigator.mediaDevices.GetUserMedia() API, including successful promise resolutions, error codes, or kTimedOut, if the promise was still pending after 8 seconds. The suffix 3 was added at milestone 145, after distribution of UserMediaRequestResult was changed. guidou@chromium.org video-cmi-apis@google.com Errors reported by SQLite while initializing or using the media-device salt database. toprice@chromium.org agpalak@chromium.org The success or failure code of MediaDevicesManager requests to enumerate video devices (ie cameras) with the camera capture service. toprice@chromium.org agpalak@chromium.org video-cmi-apis@google.com Count of MediaDevicesManager starting enumerating video devices (ie cameras) with the camera capture service, including enumerations which never finished. sangbaekpark@chromium.org media-dev-uma@chromium.org Recorded when any subsequent {MediaEngineErrorType} after the first error has occurred in MediaFoundationRenderer::MediaEngineNotifyImpl. sangbaekpark@chromium.org media-dev-uma@chromium.org Hresult corresponding to a subsequent {MF_MEDIA_ENGINE_ERR} after the first error has occurred in MediaFoundationRenderer::MediaEngineNotifyImpl. Recorded only when the first subsequent error happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Recorded when any subsequent {MF_MEDIA_ENGINE_EVENT} after the first error has occurred in MediaFoundationRenderer::MediaEngineNotifyImpl. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not any subsequent event or error occurs after the first error has occurred in MediaFoundationRenderer::MediaEngineNotifyImpl. Recorded only when the first subsequent event or error happens. vpasupathy@chromium.org media-dev-uma@chromium.org Hresult corresponding to a {MF_MEDIA_ENGINE_ERR}. Recorded when the MediaEngine hits an error from Event Notify. vpasupathy@chromium.org media-dev-uma@chromium.org This histogram is recorded when MediaEngine hits an error corresponding to the HRESULT MF_E_TOPO_CODEC_NOT_FOUND from Event Notify. This histogram records the VideoCodec as part of the name, and reports the AudioCodec, so we have both to look at the combination of codecs used when this HRESULT occurs. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a {MediaFoundationCodecPackage} was found. Recorded once when the MediaFoundation Renderer is initialized. xhwang@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer::CreateMediaEngine() fails. xhwang@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer fails to execute D3D11CreateDevice. xhwang@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer or MediaFoundationRendererClient hits an error. xhwang@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer hits an error when trying to set direct composition mode. xhwang@chromium.org media-dev-uma@chromium.org Whether or not playback has started when DRM_E_TEE_INVALID_HWDRM_STATE happens in MediaFoundationRenderer. xhwang@chromium.org media-dev-uma@chromium.org The number of video frames decoded when DRM_E_TEE_INVALID_HWDRM_STATE happens in MediaFoundationRenderer. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU's display information whether likely built-in or external when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active and non-active GPU vendor information when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU vendor ID when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of displays when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not the active GPU matches with the display GPU on multi-GPU devices when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of GPUs when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has NVIDIA active GPU associated with an external displays when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has an active GPU associated with an external displays when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Non-active GPU vendor ID when the MediaFoundationRenderer starts a playback. Reported only once such an event happens. xhwang@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer hits a playback error. Some errors are part of the normal user flow (e.g. sleep/resume) and are not a bug. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU's display information whether likely built-in or external when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active and non-active GPU vendor information when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Active GPU vendor ID when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of displays when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not the active GPU matches with the display GPU on multi-GPU devices when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org The number of GPUs when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has NVIDIA active GPU associated with an external displays when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Whether or not a multi-GPU device has an active GPU associated with an external displays when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Non-active GPU vendor ID when the MediaFoundationRenderer hits a playback error. Reported whenever such an event happens. sangbaekpark@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer detects one or more rendered video frame within the given time. Only reported once per playback. sangbaekpark@chromium.org media-dev-uma@chromium.org Time in milliseconds from when MediaFoundationRenderer reports the result whether one or more rendered video frame within the given time for {ResultReason}. Only reported once per playback. sangbaekpark@chromium.org media-dev-uma@chromium.org Recorded when the MediaFoundationRenderer hits an error when trying to set output rectangle. evliu@google.com media-dev-uma@chromium.org Whether or not the media history database exists. Called on the initialization of the profile. dalecurtis@chromium.org gabrielbrito@microsoft.com media-dev-uma@chromium.org Tracks the reason for the HTMLMediaElement being interrupted when the frame is being controlled by the MediaPlaybackWhileNotVisible permission policy and the frame is not visible. clarissagarvey@chromium.org chromeos-gfx-video@chromium.org The codec and hardware/software variant used by MediaRecorder, recorded once when the VideoTrackRecorder initializes the encoder. handellm@google.com guidou@google.com Codec queried through MediaRecorder{Query} where the result is {Result}. Logged when the call is made. hiroh@chromium.org handellm@google.com Record the correctness of the AV1 codecs string configured in MediaRecorder and queried in MediaCapabilities. It is recorded when Initialize() in MediaRecorder API is called and the capability is queried in MediaCapabilities API. handellm@google.com guidou@chromium.org The number of transformation changes received on a recorded video track. Recorded when a MediaRecorder has stopped recording. 0 means there were no frames delivered to the recorder. 1 means the first frame did or did not have transformation information attached, and no subsequent changes in transformation beyond the first frame. N means there were N-1 changes in transformation after the initial received frame. agpalak@chromium.org tovep@chromium.org Records media stream request responses for desktop-video capture media-device-update requests. This is a V4 metric replacing the V3 metric to include the new DEVICE_REMOVED outcome. agpalak@chromium.org tovep@chromium.org Records media stream request responses for display-video capture media-device-update requests. This is a V4 metric replacing the V3 metric to include the new DEVICE_REMOVED outcome. bkeen@google.com media-dev-uma@chromium.org Total duration in microseconds taken by the MediaVideoVisibilityTracker to compute occluding area. The histogram is recorded every time an element occluding a target HTMLVideoElement is found, during the ComputeOcclusion operation. Note that clients without high-resolution clocks will report 0 for very short times. bkeen@google.com media-dev-uma@chromium.org Total duration in milliseconds taken by the MediaVideoVisibilityTracker to compute occlusion. The histogram is recorded every time the MediaVideoVisibilityTracker needs to compute if a tracked HTMLVideoElement meets its specified visibility threshold. bkeen@google.com media-dev-uma@chromium.org Total number of entries in the MediaVideoVisibilityTracker ClientIdsSet. Recorded every time the tracker requests the set. bkeen@google.com media-dev-uma@chromium.org Records the percentage of the total ClientIdsSet entries that are ignored due to their DisplayItem::Type not being of "Content" type. This metric only accounts for non "Content" type entries that are present at the end of the DisplayItemList. The count stops at the first DisplayItem::Type that is of "Content" type, when traversing the DisplayItemList from tail to head. Recorded every time the tracker requests the set. bkeen@google.com media-dev-uma@chromium.org Total number of entries not added to the MediaVideoVisibilityTracker ClientIdsSet, because their DisplayItem::Type is not of "Content" type. This metric only accounts for elements that are present at the end of the DisplayItemList. The count stops at the first DisplayItem::Type that is of "Content" type, when traversing the DisplayItemList from tail to head. Recorded every time the tracker requests the set. bkeen@google.com media-dev-uma@chromium.org Total duration, in microseconds, taken by the MediaVideoVisibilityTracker to construct a ClientIdsSet. Recorded every time the tracker requests the set. Note that clients without high-resolution clocks will report 0 for very short times. bkeen@google.com media-dev-uma@chromium.org Total count of rects occluding a target HTMLVideoElement. The histogram is recorded after the MediaVideoVisibilityTracker computes whether the HTMLVideoElement meets the visibility threshold or not. Count is recorded using a histogram with {BucketSizeIncreases} bucket size increases. Note that this does not represent all elements that could be considered occluding, since MeetsVisibilityThreshold may return early depending on the size of the occluded area and the visibility threshold. bkeen@google.com media-dev-uma@chromium.org Total duration in milliseconds taken by the MediaVideoVisibilityTracker to update HTMLVideoElement s visibility. The histogram is recorded when the MediaVideoVisibilityTracker executes DidFinishLifecycleUpdate. bkeen@google.com media-dev-uma@chromium.org Total {NodesCount}, hit tested by ComputeOcclusion. The histogram is recorded after the MediaVideoVisibilityTracker computes whether the HTMLVideoElement meets the visibility threshold or not. Count is recorded using a histogram with {BucketSizeIncreases} bucket size increases. bkeen@google.com media-dev-uma@chromium.org Records the percentage of the total hit tested nodes that are {PercentageCategory}. The histogram is recorded after the MediaVideoVisibilityTracker computes whether the HTMLVideoElement meets the visibility threshold or not. henrika@chromium.org webrtc-audio@google.com Heuristically detects if the user has muted the microphone or not. Measured approximately four times per minute while an audio input stream is active. mjwilson@chromium.org hongchan@chromium.org src/third_party/blink/renderer/modules/webaudio/OWNERS Reports whether any data was sent or received by {BackendType}. Recorded once per MidiManager instantiation, upon destruction. MidiManager is instantiated when the first Web MIDI client starts a session, and destroyed when the last client ends the session. Warning: this histogram was expired from M86 to M91; data may be missing. mjwilson@chromium.org hongchan@chromium.org src/third_party/blink/renderer/modules/webaudio/OWNERS Reports sysex message size. Warning: this histogram was expired from M86 to M91; data may be missing. mjwilson@chromium.org hongchan@chromium.org src/third_party/blink/renderer/modules/webaudio/OWNERS The MidiManager instance use count, but this is not intended to understand the real API usage because this can be counted by feature scanning scripts that are often used for footprinting. You may want to track SendReceiveUsage to monitor only instances that actually send or receive MIDI messages. Warning: this histogram was expired from M86 to M91; data may be missing. dalecurtis@chromium.org media-dev-uma@chromium.org Records the status of each call to MojoAudioDecoderService::Initialize(). dalecurtis@chromium.org media-dev-uma@chromium.org Records the status of the last call to MojoAudioDecoderService::Decode() prior to destruction of the MojoAudioDecoderService. andrescj@chromium.org chromeos-gfx@chromium.org This histogram is analogous to Media.MojoVideoDecoder.Decode but for the MojoStableVideoDecoder. It's the delay between a DecoderBuffer (and encoded chunk) input and a decoded frame being produced by the remote StableVideoDecoder. Output once per successful decode. Warning: this histogram was expired from 2025-05-24 to 2025-09-01; data may be missing. hiroh@chromium.org chromeos-gfx@chromium.org Delay between a DecodeBuffer (and encoded chunk) input and a decoded VideoFrame being produced by the remote MojoVideoDecoder. Output once per successful decode. eugene@chromium.org liberato@chromium.org Total number of instances of MojoVideoDecoder used by a page (i.e. render frame) when an instance of MojoVideoDecoder encountered a decoding error or a crash during the first 150 frames of a video stream. eugene@chromium.org liberato@chromium.org Total number of instances of MojoVideoDecoder used by a page (i.e. render frame) when an instance of MojoVideoDecoder successfuly decode the first 150 frames of a video stream. hiroh@chromium.org chromeos-gfx-video@chromium.org The storage type of media::VideoFrame passed to MojoVideoEncodeAccelerator for encoding. The histogram is recorded every frame encode request. wolenetz@chromium.org media-dev-uma@chromium.org Audio codec used in Media Source Extensions playback. Set when MediaSource addSourceBuffer() is successfully called during playback. Also set twice during a successful SourceBuffer changeType() operation. See issue 535738 for reworking MSE codec histograms to record on each successfully parsed initialization segment (possibly filtered to record only when actual new codec configurations are parsed). wolenetz@chromium.org media-dev-uma@chromium.org Video codec used in Media Source Extensions playback. Set when MediaSource addSourceBuffer() is successfully called during playback. Also set twice during a successful SourceBuffer changeType() operation. See issue 535738 for reworking MSE codec histograms to record on each successfully parsed initialization segment (possibly filtered to record only when actual new codec configurations are parsed). wolenetz@chromium.org media-dev-uma@chromium.org Video codec used in Media Source Extensions playback if the media container is MP4. Set when MediaSource addSourceBuffer() is successfully called during playback. Also set twice during a successful SourceBuffer changeType() operation. See issue 535738 for reworking MSE codec histograms to record on each successfully parsed initialization segment (possibly filtered to record only when actual new codec configurations are parsed). wolenetz@chromium.org media-dev-uma@chromium.org Video codec used in Media Source Extensions playback if the media container is WebM. Set when MediaSource addSourceBuffer() is successfully called during playback. Also set twice during a successful SourceBuffer changeType() operation. See issue 535738 for reworking MSE codec histograms to record on each successfully parsed initialization segment (possibly filtered to record only when actual new codec configurations are parsed). dalecurtis@chromium.org media-dev-uma@chromium.org Reports the total bytes received over the network by a ResourceMultiBufferDataProvider instance. One is created each time a src=file playback needs to retrieve non-contiguous data over the network. Value is recorded at destruction time, so may be lost in the event of tab closure. Range is 1kb to 1gb. jophba@chromium.org openscreen-eng@google.com media-dev-uma@chromium.org The number of Cast media notifications that are currently being displayed. This is recorded when a media notification starts being displayed. jophba@chromium.org openscreen-eng@google.com media-dev-uma@chromium.org Records the type of the action (e.g. pause) whenever the user makes an action on a Cast media notification. Starting and stopping casting is recorded in Media.GlobalMediaControls.MediaCastMode.Start and Media.GlobalMediaControls.MediaCastMode.Stop. yrw@chromium.org media-dev-uma@chromium.org The number of media notifications that are currently being displayed (including ones for Cast sessions). This is recorded when a media notification starts being displayed. yrw@chromium.org media-dev-uma@chromium.org The page where the media notification is displayed to users. This is recorded when a media notification starts being displayed. yrw@chromium.org media-dev-uma@chromium.org The source of the underlying media session (e.g. ARC, web, Cast) that displayed the media notification. This is recorded when a notification is available to be shown. yrw@chromium.org media-dev-uma@chromium.org The media session action that a user clicked on a media notification (including ones for Cast sessions). guidou@chromium.org olka@chromium.org webrtc-audio-uma@google.com Duration of an audio output stream. Measured in AudioOutputController from when a stream is started until it is stopped. A stream is stopped when it is paused, closed (i.e. destructed), or when a device change event causes it to be restarted. pmolinalopez@chromium.org chromeos-gfx-video@google.com The hardware/software decoding behavior used for a PPB_VideoDecoder API instance. This UMA is recorded when the PepperVideoDecoderHost is destroyed. bkeen@google.com media-dev-uma@chromium.org Records the visual size in DIPs of the video that was allowed to enter Picture-in-Picture after meeting the minimum size constraint. The logged value is a 32-bit integer encoding width and height, both in DIPs (Device Independent Pixels): - Upper 16 bits: Width in DIPs. - Lower 16 bits: Height in DIPs. To decode the value: - width = sample >> 16 - height = sample & 0xFFFF Recorded when HTMLVideoElement::RequestEnterPictureInPicture() is called with a minimum size constraint and the video's visual size is larger than or equal to the requested minimum size. philyan@chromium.org media-dev-uma@chromium.org Records which Picture-in-Picture button was clicked. This is recorded when the user clicks on a button in the Android Picture-in-Picture window. bkeen@google.com media-dev-uma@chromium.org Records the visual size in DIPs of the video that was blocked from entering Picture-in-Picture due to a minimum size constraint. The logged value is a 32-bit integer encoding width and height, both in DIPs (Device Independent Pixels): - Upper 16 bits: Width in DIPs. - Lower 16 bits: Height in DIPs. To decode the value: - width = sample >> 16 - height = sample & 0xFFFF Recorded when HTMLVideoElement::RequestEnterPictureInPicture() is called with a minimum size constraint and the video's visual size is smaller than the requested minimum size. steimel@chromium.org liberato@chromium.org Recorded when a picture-in-picture window is closed due to a ScopedDisallowPictureInPicture object. Records whether the closed picture-in-picture window was just opened or already existed when the ScopedDisallowPictureInPicture was created. bkeen@google.com media-dev-uma@chromium.org Records whether a Picture-in-Picture request, that carries a minimum size constraint, meets the size constraint (SizeConstraintMet) or is blocked because of it (SizeConstraintNotMet). Note that this metric only tells us information about the size constraint. A Picture-in-Picture request that meets the size constraint can still fail due to other unrelated constraints. Recorded when HTMLVideoElement::RequestEnterPictureInPicture() is called with a minimum size constraint. steimel@chromium.org liberato@chromium.org Recorded when a picture-in-picture window is tucked due to a ScopedTuckPictureInPicture object. Records whether the tucked picture-in-picture window was just opened or already existed when the ScopedTuckPictureInPicture was created. bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window. The timer starts counting every time the Picture in Picture window manager receives a call to enter Picture in Picture; the time elapsed is recorded when the Picture in Picture window manager receives a call to exit Picture in Picture. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). bkeen@google.com media-dev-uma@chromium.org Total time spent on a Picture in Picture window. The timer starts counting every time the Picture in Picture window manager receives a call to enter Picture in Picture; the time elapsed is recorded when the Picture in Picture window manager receives a call to exit Picture in Picture. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). Similar to Media.PictureInPicture.Window.TotalTime, but with a maximum of 10 hours and a bucket size of 100. dalecurtis@chromium.org media-dev-uma@chromium.org Status of the media pipeline at the end of its lifecycle for audio-video streams with {VideoCodec} video codec using {Pipeline}. sangbaekpark@chromium.org media-dev-uma@chromium.org The last status of media pipeline when trying to recover from a hardware context reset. Recorded once when either the media pipeline is destroyed or we fail to recover from a subsequent error. sangbaekpark@chromium.org media-dev-uma@chromium.org The media time delta since the last hardware context reset when trying to recover from a hardware context reset. Recorded once when either the media pipeline is destroyed or we fail to recover from a subsequent error. xhwang@chromium.org media-dev-uma@chromium.org Status of the media pipeline starting process (including demuxer and renderer initialization). If the media pipeline is destroyed during the starting process nothing will be reported, but this should relatively rare. dalecurtis@chromium.org media-dev-uma@chromium.org Status of the media pipeline at the end of its lifecycle for {StreamType} streams. hiroh@chromium.org chromeos-gfx@chromium.org Time for the platform-specific (set of) video decode acceleration command(s) to be executed. Output once per decode request submit. hiroh@chromium.org chromeos-gfx-video@google.com VideoCodecProfile used to Initialize() the platform VideoDecoder implementation; this is emitted once per video (or per track, when using MSE) initialization and after verifying that the codec profile is thought to be supported. Warning: this histogram was expired from 2025-11-09 to 2025-09-01; data may be missing. dalecurtis@chromium.org media-dev-uma@chromium.org Indicates the number of rebuffers a given watch time session had. {MediaRebufferingCategories} eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Duration in milliseconds of the time it takes for a BrowserCaptureMediaStreamTrack.cropTo() call to resolve (either successfully or with an error). Note a call which never resolves won't be counted in this metric. Warning: this histogram was expired from 2025-01-07 to 2025-03-25; data may be missing. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Tracks the result of calls to BrowserCaptureMediaStreamTrack.cropTo(). Recorded when resolving the promise produced by cropTo(). Warning: this histogram was expired from 2025-01-07 to 2025-03-25; data may be missing. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org Tracks the result of calls to CropTarget.fromElement(). Specifically, this histogram tracks whether a new Promise was produced, and if not, why not. Another histogram tracks the result of new Promises, i.e. whether they were resolved or rejected. Warning: this histogram was expired from 2025-01-07 to 2025-03-25; data may be missing. eladalon@chromium.org jophba@chromium.org mfoltz@chromium.org When CropTarget.fromElement() is called for the first time on a given Element, a new Promise is produced. This histogram tracks the result of this Promise - whether it was resolved or rejected. Warning: this histogram was expired from 2025-01-07 to 2025-03-25; data may be missing. jophba@chromium.org openscreen-eng@google.com Measured audio content transfer bitrate while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Audio channel layout used while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Audio codec used while remoting content. jophba@chromium.org openscreen-eng@google.com Audio sampling rate while remoting audio content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Audio sampling rate while remoting audio content (atypical values, in Hz). NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Whether the given media is compatible with media remoting. Recorded whenever the conditions are met to start remoting (e.g. the media element is the dominant page content and is not paused). jophba@chromium.org openscreen-eng@google.com Tracks whether a web page allows content to be remoted. Recorded when the media player finishes loading and when the site changes this attribute afterwards. jophba@chromium.org openscreen-eng@google.com Measures the duration of each remoting session. jophba@chromium.org openscreen-eng@google.com Tracks the reason that a session failed to start. jophba@chromium.org openscreen-eng@google.com Tracks the trigger for starting a remoting session. jophba@chromium.org openscreen-eng@google.com Tracks the trigger for stopping a remoting session. {RemotingSessionDuration} jophba@chromium.org openscreen-eng@google.com Measures the duration of each remoting session shorter than 15 seconds. jophba@chromium.org openscreen-eng@google.com Measures how long, from the start of a remoting session, until content began playing out on the remote device. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Measures how long, from the start of a remoting session, until a message was received from the remote device indicating initialization succeeded. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Tracks whether audio or video or both are remoted. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Aspect ratio of video while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Measured video content transfer bitrate while remoting content. jophba@chromium.org openscreen-eng@google.com Video codec used while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Video codec profile used while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Video width while remoting content. NOTE: was expired 2025-02-01 to 2025-03-12, some data may be missing. jophba@chromium.org openscreen-eng@google.com Pixels-per-second in a video and whether the receiver supports its playback. Recorded whenever we are about to start media remoting a video. kron@chromium.org webrtc-video@google.com 10 times the average queue length when Render() is called in the RTC low-latency video renderer. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Per mille of frames drained in the RTC low-latency video renderer. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Per mille of frames dropped in the RTC low-latency video renderer. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Number of times drain mode is entered. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com The maximum queue length that is observed when Render() is called in the RTC low-latency video renderer. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Number of times the maximum queue size is exceeded and the entire queue is dropped. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Per mille of render times where the queue is empty and there is no new frame to render. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Number of times the reduce steady state queue feature is activated. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Total number of frames enqueued to the RTC low-latency video renderer. Repeatedly measured with a period of 100 s for as long as the stream is active. kron@chromium.org webrtc-video@google.com Number of times we try to render a new frame. Repeatedly measured with a period of 100 s for as long as the stream is active. posciak@chromium.org liberato@chromium.org webrtc-video@google.com Counts of video decode errors reported to RTCVideoDecoder, recorded when an error is reportd to RTCVideoDecoder. Also used for DecoderStream. Expired in M83 and re-added in M92. Warning: this histogram was expired between 2023-04-16 to 2023-04-20; data may be missing. kron@chromium.org webrtc-video@google.com The reason for fallback to software decoding for the codec {Codecs}. Reported when a fallback to software decoding occurs. liberato@chromium.org webrtc-video@google.com Time from decoder creation until the first frame is decoded. sprang@chromium.org chromeos-gfx@chromium.org Indicates whether we were successful in initializing hardware video decoder for use in the RTC pipeline. kron@chromium.org webrtc-video@google.com Initialization latency of the hardware video decoder that is used in the RTC pipeline. Recorded directly after a decoder is initialized. liberato@chromium.org webrtc-video@google.com Max number of frames sent for video decode via the DecoderStream adapter, that have not also returned a decoded video frame. The metric is emitted once per RTCVideoDecoderStreamAdapter instance, as the max observed value over that instance's lifetime. Warning: this histogram was expired between 2022-08-14 to 2023-04-20; data may be missing. sprang@chromium.org chromeos-gfx@chromium.org Video codec profile used in RTC video decoder. kron@chromium.org webrtc-video@google.com Reinitialization latency of the hardware video decoder that is used in the RTC pipeline. Recorded directly after a decoder is reinitialized. hiroh@chromium.org chromeos-gfx-video@google.com The duration of initializing a hardware encoder in WebRTC API. It is recorded whenever RTCVideoEncoder::InitEncode() is called. Warning: this histogram was expired from 2024-09-30 to 2025-09-01; data may be missing. sprang@chromium.org chromeos-gfx@chromium.org Indicates whether we were successful in initializing hardware video encoder for use in the RTC pipeline. sprang@chromium.org chromeos-gfx@chromium.org Video codec profile used in RTC video encoder. hiroh@chromium.org sprang@chromium.org chromeos-gfx@chromium.org Records if the {Codecs} encoder was torn down because the stream ended, or if it was due to an encoder error. Recorded once when shutting down an accelerated (or out of process) video encoder. kron@chromium.org webrtc-video@google.com Records the mode that is used in the ScreenCaptureKit Fullscreen module if the selected window to capture belongs to a supported application. The mode is reported once per captured window when the fullscreen module is created. Warning: this histogram was expired from 2026-01 to 2026-03; data may be missing. tovep@chromium.org kron@chromium.org brandstrom@chromium.org Records lifecycle and modification events for SCContentSharingPicker capture sessions on macOS, including opening the picker, updating the window list, removal of the primary app, and requests for application-audio. Each event is only logged once per session, when it first happens. tovep@chromium.org kron@chromium.org brandstrom@chromium.org Records when the macOS native sharing picker triggers a stop_audio_callback and when application audio capture is actually stopped. tovep@chromium.org kron@chromium.org eladalon@chromium.org Records calls to SCContentSharingPicker and responses to the SCContentSharingPickerObserver. steimel@chromium.org media-dev-uma@chromium.org Time during which a media session has been active, in other words, the time between an activation and deactivation, without counting time while it was suspended. If a session is activated after being deactivated, there will be two entries. For example, if a user plays a song but is interrupted by a phone call, it will only account for the song playing time. steimel@chromium.org media-dev-uma@chromium.org Recorded when EnterPictureInPicture or EnterAutoPictureInPicture is called on a MediaSessionImpl. Records why picture-in-picture was triggered (whether it was for the default handler or a website-provided one, and whether the trigger was manual or automatic). philyan@chromium.org media-dev-uma@chromium.org The number of times the user paused playback of a media session using other means than the pause button on the page. bkeen@google.com media-dev-uma@chromium.org Time during which Picture in Picture windows have been open during a MediaSession. The time spent is accumulated every time a Picture in Picture window is opened using MediaSession and subsequently closed; The total time is recorded when the MediaSession is destroyed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). bkeen@google.com media-dev-uma@chromium.org Time during which Picture in Picture windows have been open during a MediaSession. The time spent is accumulated every time a Picture in Picture window is opened using MediaSession and subsequently closed; The total time is recorded when the MediaSession is destroyed. This metric is recorded regardless of the Picture in Picture window type (document vs video), and of the reason for closing the window (UI interaction, returning back to opener tab, etc.). Similar to Media.Session.PictureInPicture.TotalTimeForSession, but with a maximum of 10 hours and a bucket size of 100. steimel@chromium.org media-dev-uma@chromium.org The number of times the user started playback of a media session using other means than the play button on the page. dalecurtis@chromium.org media-dev-uma@chromium.org Video codec used in plain src= (not MSE) HTML5 media if the media container is MP4. dalecurtis@chromium.org media-dev-uma@chromium.org Video codec used in plain src= (not MSE) HTML5 media if the media container is WebM. kron@google.com eladalon@google.com This histogram tracks the percentage of callbacks where there was no shareable content returned from the OS. This is recorded in the destructor of ThumbnailCapturerMac. The metric is rounded upwards so that a single error shows up as at least 1%. dalecurtis@chromium.org media-dev-uma@chromium.org Time in milliseconds from when WebMediaPlayerImpl starts loading until the first video frame has been shown. dalecurtis@chromium.org media-dev-uma@chromium.org Time in milliseconds from when WebMediaPlayerImpl starts loading until metadata is known. dalecurtis@chromium.org media-dev-uma@chromium.org Time in milliseconds from when WebMediaPlayer starts loading until it has buffered enough to start playback. tmathmeyer@chromium.org media-dev@chromium.org Reports the final pipeline status for playbacks that had at least one audio or video track change. This is logged at the end of playback, either on destruction or when an error occurs. kron@chromium.org video-cmi-apis@google.com Records the flow and user interactions related to checking system audio capture permission on macOS during getDisplayMedia. This includes whether the check is enabled, when it is initiated, the result of the check (granted/denied), and the user's subsequent actions if permission is denied (e.g., opening settings, cancelling, or sharing with/without audio). Recorded at different stages: Enabled/Disabled: When the media picker dialog is opened. CheckInitiated: When the permission check is started. PermissionGranted/Denied: When the permission check completes. SystemSettingsOpenedAfterDenial: The first time the open system settings button is clicked. CancelSharingAfterDenial: When the user cancels the dialog after a permission denial. Share...AfterDenial: When the user accepts a selected source after a permission denial. eladalon@chromium.org mfoltz@chromium.org When getDisplayMedia() is called, the user is shown a list of tabs, windows and screens they can choose to capture. If the user highlights a discarded tab, no preview is shown - which is a problem. This histogram tracks how often the user sees at least one missing preview due to highlighting a discarded tab. (Contrast this with SelectedTabDiscardStatus.) The histogram is recorded when the media-picker dialog is closed - either through the user accepting or rejecting the dialog, or if the document that called getDisplayMedia() is unloaded (e.g. if the tab is closed). eladalon@chromium.org mfoltz@chromium.org When getDisplayMedia() is called, the user is shown a list of tabs, windows and screens they can choose to capture. If the user highlights a discarded tab, no preview is shown - which is a problem. This histogram tracks how often the user ends up choosing to share a discarded tab. (Contrast this with HighlightedTabDiscardStatus.) The histogram is recorded when the media-picker dialog is closed - either through the user accepting or rejecting the dialog, or if the document that called getDisplayMedia() is unloaded (e.g. if the tab is closed). eladalon@chromium.org tovep@chromium.org Record how many sources of type {Type} were available for the user to choose from. Recorded when the dialog is closed (user selected a source, cancelled, or closed the tab that owns the dialog). eladalon@chromium.org fbeaufort@chromium.org Records the result of the user's interaction with the media picker dialog which is displayed following a call to getDisplayMedia that results in the basic flow (preferCurrentTab either unspecified or is false). eladalon@chromium.org guidou@chromium.org Records whether the display-capture permission policy allows/disallows this call to getDisplayMedia. tovep@chromium.org eladalon@chromium.org kron@chromium.org Records whether the user has screen recording permission when the DesktopMedia picker dialog is opened. eladalon@chromium.org fbeaufort@chromium.org Records the result of the user's interaction with the media picker dialog which is displayed following a call to getDisplayMedia where preferCurrentTab was specified. tovep@chromium.org eladalon@chromium.org Records which controls are clicked in the TabSharingInfoBar. The histogram is recorded for each click on such a control. tovep@chromium.org olka@chromium.org agpalak@chromium.org rtc-meet-in-chrome@google.com Recorded after a Web application calls getDisplayMedia() {Flow}, after the user chooses to share a display surface of type {Type}. (Not recorded if the user rejects the prompt.) Tracks the state of the audio toggle at the time when the user approved the capture. If the audio toggle is not present, this histogram distinguishes the reason for its absence. Note that `AudioSelectionPreferred` is a subset of `BasicFlow` (which is logged for all requests). Also note that `WindowsAppAudio` and `WindowsSystemAudio` are subsets of `Windows` where the option to share application audio or system audio (respectively) is provided. tovep@chromium.org eladalon@chromium.org The time-duration the DesktopMediaPickerDialog is opened when getDisplayMedia is called with the preferCurrentTab constraint either set to true (PreferCurrentTabFlow) or unspecified/false (BasicFlow). The duration is recorded each time the dialog is closed. eladalon@chromium.org tovep@chromium.org When the user shares a tab, window or screen, the browser shows the user some UX elements which can control the session - stop sharing, hide controls, share something else, change active tab, etc. Which UX elements are available depends on what is shared as well as other factors. The histograms defined here track which controls the user interacted with, if any. Recording takes place when the interaction happens; if no interaction occurs, this is recorded when the controls are hidden from the user (typically when the capture session ends through other means). It should be noted that, while the name indicates getDisplayMedia(), this histogram is actually recorded for any screen-sharing session, including casting and extension APIs. dalecurtis@chromium.org media-dev-uma@chromium.org The amount of time taken to leave the underflow state (i.e. resume playback) for playbacks. This doesn't report initial zero samples, which was previously used to compensate for playbacks that don't rebuffer. dalecurtis@chromium.org media-dev-uma@chromium.org URL scheme used with HTML5 media; only recorded for src=URL playbacks and not for Media Source Extensions playbacks. Each URL provides one sample. hiroh@chromium.org chromeos-gfx-video@google.com Records errors during normal V4L2VideoDecoder operations. These can happen during initialization, decode or other internal state changes. Multiple errors can be recorded during the object lifetime. Warning: this histogram was expired from 2024-05-19 to 2025-09-01; data may be missing. tmathmeyer@chromium.org media-dev-uma@chromium.org Records the usage of VaapiVideoDecoder VaapiVideoDecodeAccelerator based on vulkan support and Vaapi driver version on linux. This is recorded on GPU process startup when hardware accelerated video decoding support is checked. hiroh@chromium.org chromeos-gfx@chromium.org The codec-specific delegate in VaapiVideoDecoder has returned an error from Decode(). This could be a parse error, or a VA error itself. hiroh@chromium.org chromeos-gfx-video@google.com Whether the creation of VaapiWrapper succeeded or not inside VaapiVideoDecoder. Warning: this histogram was expired from 2023-02-12 to 2025-09-01; data may be missing. hiroh@chromium.org chromeos-gfx-video@google.com Whether the call to VaapiWrapper's VADisplayState::Initialize() succeeded or not. Warning: this histogram was expired between 2023-02-12 to 2023-04-20; data may be missing. andrescj@chromium.org chromeos-gfx@chromium.org The response given to the client by VaapiJpegDecodeAccelerator for a decode request. This is recorded when the decode succeeds or fails. The recorded value corresponds to a MjpegDecodeAccelerator::Error. hiroh@chromium.org chromeos-gfx-video@google.com Whether the creation of VaapiWrapper succeeded or not inside VaVDA.Warning: this histogram was expired from 2023-02-12 to 2025-09-01; data may be missing. evliu@google.com dalecurtis@chromium.org media-dev-uma@chromium.org Records the autoplay source of videos. This includes Media.Video.Autoplay.Muted. evliu@google.com dalecurtis@chromium.org media-dev-uma@chromium.org Records muted video started playing with play() become visible at some point. The UMA for false is not complete since it is recorded in a destructor which is garbage-collected. Please subtract Media.Video.Autoplay.Muted "play() method" count with the true count of this histogram to obtain the real false count. evliu@google.com dalecurtis@chromium.org media-dev-uma@chromium.org Records the offscreen playing duration of a muted video autoplaying from play() method. evliu@google.com dalecurtis@chromium.org media-dev-uma@chromium.org Status of the unmute action on a video that autoplayed because it was muted. toprice@chromium.org video-cmi-apis@google.com The Mac system permission state for camera. Logged once at browser startup. For more information on the values, see https://developer.apple.com/documentation/avfoundation/avauthorizationstatus. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. toprice@chromium.org video-cmi-apis@google.com The Mac system permission state for camera at the time of a user media request. Logged when the system permission is checked. If the permission is "not determined" this is logged, permission is requested, and the resulting permission (from the user response) is also logged. For more information on the values, see https://developer.apple.com/documentation/avfoundation/avauthorizationstatus. Warning: this histogram was expired from 2020-03-01 to 2022-03-09; data may be missing. avi@chromium.org mark@chromium.org The Mac system permission state for screen capture. Logged once at browser startup and when attempting to screen capture. Requires macOS 10.15+. Samples will not be collected on earlier macOS versions. Warning: this histogram was expired from 2024-02-11 to 2024-09-16; data may be missing. eugene@chromium.org media-dev-uma@chromium.org Video playback roughness for a 100s interval. Suffixed by the framerate. {VideoFrameRateRange} hiroh@chromium.org chromeos-gfx-video@chromium.org jophba@chromium.org Video Capture Device captured aspect ratio, as a rounded integer multiplied by 100. The collection is made in the VideoCaptureController upon reception of the first frame. Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. herre@google.com video-cmi-apis@google.com Time during VideoSourceImpl startup taken to create a video_capture::Device object. Only recorded if the creation was successful. Is a subset of Media.VideoCapture.StartSourceSuccessLatency corresponding to Device creation, rather than capture startup in the device. armax@chromium.org video-cmi-mpp@google.com Time it takes from the moment that a VideoCaptureController is requested to start to the moment the first video frame arrives at VideoCaptureController::OnFrameReadyInBuffer(). bryantchandler@chromium.org openscreen-eng@google.com This metric records the pixel format of the active camera video feed at start, and everytime the pixel format changes. eshr@google.com handellm@google.com bryantchandler@chromium.org openscreen-eng@google.com Counts each pixel format an enumerated video capture device supports. This is recorded during the first device enumeration per Capture process launch. (This is usually once per launch of Chrome unless the Capture process crashes.) bryantchandler@chromium.org eshr@google.com handellm@google.com jophba@chromium.org openscreen-eng@google.com Counts each resolution supported by an enumerated video capture device. These are categorized by designation (eg. QVGA, HD, 4KUHD, etc) instead of pixel count. This is recorded during the first device enumeration per Capture process launch. (This is usually once per launch of Chrome unless the Capture process crashes.) Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. hiroh@chromium.org chromeos-gfx-video@chromium.org guidou@chromium.org armax@chromium.org Breaks down the events counted in Media.VideoCaptureManager.Event bucket "Stopping video capture due to error" by the origin of the error. This allows narrowing down what is causing errors. An event for this histogram is emitted once for each time a client disconnects from a video capture session because the session has reported an error. hiroh@chromium.org chromeos-gfx-video@chromium.org guidou@chromium.org armax@chromium.org handellm@google.com jophba@chromium.org Video Capture Device frame rate requested by VideoCaptureManager on AllocateAndStart(). The collection is made in the VideoCaptureController upon reception of the first frame. hiroh@chromium.org chromeos-gfx-video@chromium.org handellm@google.com jophba@chromium.org Video Capture Device captured frame height in pixels. The collection is made in the VideoCaptureController upon reception of the first frame. Warning: this histogram was expired from 2023-12-31 to 2025-03-25; data may be missing. Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. avi@chromium.org mark@chromium.org A classification of the type of AVCaptureDevice being used for capture. This UMA is recorded once per opening of the device. guidou@chromium.org video-cmi-apis@google.com An enumeration count of whether reaction effects are enabled and can be triggered by gestures. This is recorded once per opening of the camera. kron@google.com video-cmi-mpp@google.com A boolean count of how often a valid color space can be determined from the transformed buffer in VideoCaptureDeviceAVFoundation. This is recorded for the first frame in didOutputSampleBuffer that has been passed through the transformer. jophba@chromium.org openscreen-eng@google.com The scalar multiplier used for adjusting the content size during tab capture to align with the requested capture size, multiplied by 100. Recorded when capture of a web contents is started, the content size of the capture changes, and when capture stops. Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. jophba@chromium.org openscreen-eng@google.com The number of times the scale override changed in a single capture session. Recorded when capture of a web contents is stopped. Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. toprice@chromium.org guidou@chromium.org Counts the start attempts for video capture, to be compared with the StartOutcome enum histogram. agpalak@chromium.org toprice@chromium.org rtc-meet-in-chrome@google.com Counts detailed outcomes of first starting {ApiType}, as a breakdown of Media.VideoCapture.StartOutcome based on the error codes which caused failures, or kNone if we started successfully. Can also be viewed as the subset of reports to Media.VideoCapture.Error which occur before VideoCaptureImpl first transitions to STARTED. Recorded in VideoCaptureImpl::OnStateChanged() when a video capture attempt finishes, either successfully transitioning to STARTED or failing. toprice@chromium.org guidou@chromium.org Counts the times Starting video capture results in success or failure (due to eg timeouts etc). herre@google.com video-cmi-apis@google.com Total time for a VideoSourceImpl to start a device to serve the first push subscription mojo connection. Only recorded if starting is successful. wtlee@chromium.org chromeos-camera-app-eng@google.com Records when attempting to access a camera and the value represents whether the camera is shared due to multiple camera access. wtlee@chromium.org chromeos-camera-app-eng@google.com Records when attempting to share a camera and the value represents whether the origin requesting to share the camera stream is the same origin initiating the video capture device. hiroh@chromium.org chromeos-gfx-video@chromium.org guidou@chromium.org armax@chromium.org jophba@chromium.org An event for this histogram is emitted once for each time a video frame is dropped for a {StreamType} video source, but gets suppressed after `MediaStreamVideoTrack::kMaxConsecutiveFrameDropForSameReasonCount` consecutive drops. Logging resumes again if another frame is delivered or if the frame drop reason changes. The frame drop is recorder on a per-track basis (i.e. cloned tracks also log) and includes out-of-process frame drops (e.g. a DeviceCapture webcam source dropping frames in the capture process). Warning: this histogram was expired from 2024-03-03 to 2025-03-25; data may be missing. Warning: this histogram was expired from 2026-03-25 to 2026-06-10; data may be missing. hiroh@chromium.org chromeos-gfx-video@chromium.org handellm@google.com jophba@chromium.org Video Capture Device captured frame width in pixels. The collection is made in the VideoCaptureController upon reception of the first frame. Warning: this histogram was expired from 2024-05-05 to 2024-05-21; data may be missing. ilnik@chromium.org video-cmi-mpp@chromium.org Error codes received by VideoCaptureDeviceMFWin when checking for D3D11 device removal reason. ilnik@google.com video-cmi-mpp@google.com Counts the difference between consecutive capture begin times received from MFSamples. Recorded on each received sample. Offset by +150ms to allow recording of negative values. ilnik@google.com video-cmi-mpp@google.com Counts the difference between local chrome clock and MFTIME clock. Recorded on each received sample. Offset by +150ms to allow recording of negative values. ilnik@google.com video-cmi-mpp@google.com Counts the pixel formats produced by the VideoCaptureDevice on Windows. This is recorded when the camera is opened. ilnik@google.com video-cmi-mpp@google.com Counts the pixel formats used internaly by Windows VideoCaptureEngine. This is recorded when the camera is opened. ilnik@google.com video-cmi-mpp@google.com Determine what proportion of frames might actually benefit from zero-copy on Windows. This is recorded when the camera is opened and we get the texture from IMFCaptureEngine. ilnik@google.com video-cmi-mpp@google.com Counts the pixel formats requested by the consumer on Windows. This is recorded when the camera is opened. ilnik@google.com handellm@google.com video-performance-team@google.com The Capture API that is used on Windows. This is recorded when the camera is opened. toprice@chromium.org video-cmi-apis@google.com Error codes received by VideoCaptureDeviceMFWin on Windows which caused a kWinMediaFoundationGetMediaEventStatusFailed error, ending video capture. Warning: this histogram was expired from 2025-03-30 to 2025-06-03; data may be missing. guidou@chromium.org webrtc-dev@chromium.org Counts how many retries are needed for calls to MediaFoundation function GetDeviceStreamCategory before getting a result different from MF_E_INVALIDREQUEST or giving up. guidou@chromium.org webrtc-dev@chromium.org Counts how many retries are needed for calls to MediaFoundation function GetDeviceStreamCount before getting a result different from MF_E_INVALIDREQUEST or giving up. handellm@google.com ccameron@chromium.org Indicates which desktop capture implementation and DesktopID::Type was used for a desktop capture session. Recorded on instantiation of the desktop capturer. Warning: this histogram was expired from 2025-07-27 to 2025-09-05; data may be missing. dalecurtis@chromium.org Video codec used in HTML5 media. dalecurtis@chromium.org media-dev-uma@chromium.org Whether Chrome had to fall back to a secondary video decoder with {VideoCodec} video codec after the primary decoder failed reinitialization. chcunningham@chromium.org media-dev-uma@chromium.org Indicates whether we were successful performing the operation to {DbOperation}. Recorded once the operation completes. chcunningham@chromium.org media-dev-uma@chromium.org Indicates duration of time performing the operation to {DbOperation}. Recorded once the operation completes or times out. Reported for all users regardless of clock resolution. eugene@chromium.org media-dev-uma@chromium.org Records if the MediaFoundation {VideoCodec} encoder returns a delta frame on an explicit key frame request. Recorded on every key frame request. eugene@chromium.org media-dev-uma@chromium.org Records if the {VideoCodec} encoder was torn down because the stream ended, or if it was due to an encoder error. Recorded once when shutting down an accelerated (or out of process) video encoder. eugene@chromium.org media-dev-uma@chromium.org Records the usage and success rate of D3D12 video encode accelerator for {VideoCodec} codec. kInit is recorded every time VEA Initialize() is called. kSuccess is recorded only when VEA initialization completes successfully. Success percentage = (kSuccess count / kInit count) * 100. eugene@chromium.org media-dev-uma@chromium.org Records if the {VideoCodec} encoder was torn down because the stream ended, or if it was due to an encoder error. Recorded once when shutting down an accelerated (or out of process) video encoder on Android. eugene@chromium.org media-dev-uma@chromium.org Records the initialization status of the NdkVideoEncodeAccelerator for {VideoCodec}. Recorded every time Initialize() is called. philyan@google.com media-dev-uma@chromium.org Records the underlying platform capability for temporal layer encoding on Android, independent of Finch experiment flags or strict OS version enforcement in the NDK VEA. Logged during encoder initialization if multiple temporal layers are requested. eugene@chromium.org media-dev-uma@chromium.org Average encoding latency in milliseconds per frame for the {VideoCodec} codec when using the {Impl}. Recorded on every key frame or when the encoding session is destroyed so remaining samples are reported. hiroh@chromium.org media-dev-uma@chromium.org The hundredth of a resolution area (i.e. width x height /100) configured in a video encoder. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org The number of successfully encoded frames. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org The height configured in a video encoder. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org Video codec profile used in a video encoder. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org The last encoder status in a video encoder. If an error occurs, then non kOk value is recorded. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org SVC Scalability mode configured in a video encoder. Recorded when a video encoder is destroyed or reconfigured. hiroh@chromium.org media-dev-uma@chromium.org The width configured in a video encoder. Recorded when a video encoder is destroyed or reconfigured. kron@chromium.org video-performance-team@google.com chromeos-gfx@chromium.org Delay between a VideoFrame being decoded and it being consumed by the OS presentation API (on ChromeOS, this includes the display controller too). Recorded when VideoFrameSubmitter::OnBeginFrame() is called based on the frame timing details that is passed as parameter. kron@chromium.org video-performance-team@google.com chromeos-gfx@chromium.org Delay between a VideoFrame being decoded and it being handed over to the CompositorFrameSink, essentially capturing the buffering in the Renderer. This value is strictly included in Media.VideoFrameSubmitter.{Source}.PresentationDelay. Recorded when the composition frame is created. xhwang@chromium.org media-dev-uma@chromium.org The height of the first video frame in an HTML5 video for {PlaybackType} playbacks. Reported when the first video frame is available. dalecurtis@chromium.org media-dev-uma@chromium.org Indicates how many cadence changes have occurred during playback, a zero value is emitted at the beginning of playback. Subsequent values are emitted during video rendering for each cadence change (up to a maximum of 10). dalecurtis@chromium.org media-dev@chromium.org The format of each VideoFrame passed to VideoResourceUpdater. Recorded prior to resources being obtained for passing to Viz. dalecurtis@chromium.org Watch time is defined as the amount of elapsed media time for audio+video media aggregated per player instance. A minimum of 7 seconds of unmuted, foreground media must be watched to start watch time monitoring. Watch time is checked on a regular basis and reported to UMA upon one of the stop events mentioned below or at player destruction if none occur prior. Any one of paused, hidden, or muted is sufficient to stop watch time metric reports. Each of these has a hysteresis where if the state change is undone within some time, the watch time will be counted as uninterrupted. Power events (on/off battery power) have a similar hysteresis, but unlike the aforementioned properties, will not stop metric collection. Each seek event will result in a new watch time metric being started and the old metric finalized as accurately as possible. {MediaWatchTimeCategories} handellm@google.com webrtc-video@google.com 10x the harmonic frame rate of the video frames that were presented by the compositor. This is computed as one over the weighted average of frame durations where the weights are the durations themselves. This is a measure of the effective frame rate of the video, penalizing hitches heavily. This metric is only recorded for non-screencast video. Higher is better. The metric is reported every 10 seconds provided frames have been presented. handellm@google.com webrtc-video@google.com The number of times the compositor presented consecutive frames whose duration since last displayed frame was negative. The metric is reported every 10 seconds provided relevant frames have been presented. kron@chromium.org webrtc-video@google.com Returns the reason why the render buffer was cleared in WebMediaPlayerMsCompositor. Recorded in the call to EnqueueFrame() if the render buffer is cleared. If multiple conditions apply, only the first matching enum is reported. handellm@google.com webrtc-video@google.com A RMSE-like measure of the difference between the presented and captured frame durations. This metric can handle both isochronous as well as variable frame rate video. Lower is better. The metric is reported every 10 seconds provided relevant frames have been presented. kron@chromium.org webrtc-video@google.com The video codec profile that was used when calling GetPerfInfo. Recorded for each call to GetPerfInfo if certain sanity checks pass. kron@chromium.org webrtc-video@google.com The video codec profile that was provided to SavePerfRecord. Recorded for each call to SavePerfRecord if certain sanity checks pass. kron@chromium.org webrtc-video@google.com Tracks how the smoothness prediction value was determined (smooth by default, smooth from data, not smooth from data, implicitly smooth, smooth override, or implicitly not smooth) multiplexed with the configuration (codec, pixels, hardware_accelerated). See the code for details. This gives a sparse histogram that is best interpreted using a script for demultiplexing. The value is reported each time either encodingInfo() or decodingInfo() are called and requests a smoothness prediction from WebrtcVideoPerfHistory. kron@chromium.org webrtc-video@google.com Tracks the volatilty of the smoothness predictions after updates to the database, that is, if the smoothness prediction changes or stays at the same value. Recorded after each update to the WebRTC MediaCapabilities database if there was an existing record for the corresponding configuration. kron@chromium.org webrtc-video@google.com Indicates whether we were successful performing the operation to {DbOperation}. Recorded once the operation completes. kron@chromium.org webrtc-video@google.com Indicates duration of time performing the operation to {DbOperation}. Recorded once the operation completes or times out. Reported for all users regardless of clock resolution. hiroh@chromium.org chromeos-gfx-video@chromium.org Error codes reported by libva (via VaapiWrapper) while being used from the specified client name. {VaapiClientName} Warning: this histogram was expired from 2025-06-01 to 2025-09-01; data may be missing. steimel@chromium.org media-dev-uma@chromium.org Recorded when the MediaLauncherActivity starts up. Records the reaosn that MediaLauncherActivity is enabled. bryantchandler@chromium.org openscreen-eng@google.com Records the number of camera devices available in the PageInfo combobox. Note: There is a change for the zero device case starting from M128 where we no longer record the zero case if the list of devices is not initialized yet. bryantchandler@chromium.org openscreen-eng@google.com Records the number of microphones (audio input) devices available in the PageInfo combobox. Note: There is a change for the zero device case starting from M128 where we no longer record the zero case if the list of devices is not initialized yet. bryantchandler@chromium.org openscreen-eng@google.com Records the number of camera devices available in the Permissions combobox. Note: There is a change for the zero device case starting from M128 where we no longer record the zero case if the list of devices is not initialized yet. bryantchandler@chromium.org openscreen-eng@google.com Records the number of microphones (audio input) devices available in the Permissions combobox. Note: There is a change for the zero device case starting from M128 where we no longer record the zero case if the list of devices is not initialized yet. ahmedmoussa@google.com openscreen-eng@google.com Records the kind of user interaction with combobox shown in {UiLocation} media preview. This is recorded during media preview destructor. bryantchandler@chromium.org openscreen-eng@google.com Records the number of previews shown for camera devices in use on PageInfo. bryantchandler@chromium.org openscreen-eng@google.com Records the height in pixels of the camera frames rendered in the PageInfo preview (not the actual height of the preview itself). bryantchandler@chromium.org openscreen-eng@google.com Records the number of previews shown for microphones (audio input) devices in use on PageInfo. bryantchandler@chromium.org openscreen-eng@google.com Records the height in pixels of the camera frames rendered in the Permissions preview (not the actual height of the preview itself). bryantchandler@chromium.org openscreen-eng@google.com Records the actual FPS of the {UiLocation} camera preview for the time it's on screen. ahmedmoussa@google.com openscreen-eng@google.com Records the duration in which the camera took till getting the first frame. This would help measuring the delay of camera stream. bryantchandler@chromium.org openscreen-eng@google.com Records the actual FPS of the {UiLocation} camera preview for the time it's on screen. bryantchandler@chromium.org openscreen-eng@google.com Records the percentage of frames that we got from the camera (ActualFPS) that were actually rendered. Recorded when the {UiLocation} preview is closed. ahmedmoussa@google.com openscreen-eng@google.com Records the duration till media preview dialog closes if there were no frames received. ahmedmoussa@google.com openscreen-eng@google.com Records the duration in which media preview dialog is actually receiving camera feed. If the user switched between multiple cameras, a sum of the camera feeds durations is recorded. If the dialog closes in under 50 ms, this is treated the same way as if we didn't receive any frames. This would help verifying whether the preview was actually seen by the user or not. ahmedmoussa@google.com openscreen-eng@google.com Records video capture errors received from the {UiLocation} camera preview. ahmedmoussa@google.com openscreen-eng@google.com Records the length of time the preview is on-screen. As a simplification, we will just record the length of time where {UiLocation} is open. Recorded in the destructor of {UiLocation}. jophba@chromium.org openscreen-eng@google.com Round trip time for a Cast app availability request. Can be suffixed with Success or Failure. {MediaRouterSuccess} jophba@chromium.org openscreen-eng@google.com Whether opening Cast channel succeeds or not. Recorded when all opening channel attempts (including retry attempts) finish. jophba@chromium.org openscreen-eng@google.com Errors encountered on a Cast channel. Recorded when a Cast channel fails to open, or when an opened channel fails to respond to keepalive ping request and times out. jophba@chromium.org openscreen-eng@google.com The number of connected Cast devices. Recorded when browser finishes discovering Cast devices. Recording happens roughly once per hour. jophba@chromium.org mfoltz@chromium.org openscreen-eng@google.com The number of known Cast devices. Recorded when browser finishes discovering Cast devices. Recording happens roughly once per hour. jophba@chromium.org openscreen-eng@google.com The source of discovery for a newly-created Cast sink. jophba@chromium.org openscreen-eng@google.com The type of app that the receiver device choose to launch. Recorded when receiving a receiver status response to the launch request. jophba@chromium.org openscreen-eng@google.com Duration in milliseconds taken to fail to open a cast channel. Recorded when one opening channel attempt fails. jophba@chromium.org openscreen-eng@google.com Duration in milliseconds taken to successfully open a cast channel. Recorded when one opening channel attempt succeeds. jophba@chromium.org openscreen-eng@google.com Total time to launch a Cast Streaming mirror session. jophba@chromium.org openscreen-eng@google.com Total length of a Cast Streaming mirror session of any type, including the time spent in media remoting. jophba@chromium.org openscreen-eng@google.com Total length of a Cast Streaming Offscreen Tab mirror session. jophba@chromium.org openscreen-eng@google.com Total length of a Cast Streaming Screen mirror session. jophba@chromium.org openscreen-eng@google.com Total length of a Cast Streaming mirror session of type Tab and NOT of types offscreen tab or local file. This includes the time spent in media remoting. jophba@chromium.org openscreen-eng@google.com Whenever a Cast Streaming session is successfully started, record if it was for a Tab or Desktop mirroring session. jophba@chromium.org openscreen-eng@google.com The number of available DIAL devices. Recorded when browser finishes discovering DIAL devices. Recording happens roughly once per hour. jophba@chromium.org openscreen-eng@google.com The result of a DIAL CreateRoute request. Recorded when the user requests to create a media route to a DIAL device. jophba@chromium.org openscreen-eng@google.com Result from parsing DIAL device description XML text. Recorded when utility process returns a DIAL device description object to the DIAL Media Route Provider. jophba@chromium.org openscreen-eng@google.com The result of a DIAL app info request. Recorded when an app info request is issued to a DIAL device. jophba@chromium.org openscreen-eng@google.com The number of known DIAL devices. Recorded when browser finishes discovering DIAL devices. Recording happens roughly once per hour. jophba@chromium.org openscreen-eng@google.com Whether the local network access permission is granted when the local discovery starts. Recorded once per browser session. Recorded on macOS 15 or later. jophba@chromium.org openscreen-eng@google.com Location the user clicked to open the Media Router dialog. jophba@chromium.org openscreen-eng@google.com Records when a hardware encoder gets disabled during a mirroring session, which prompts a renegotiation without that hardware encoder configuration being offered. jophba@chromium.org openscreen-eng@google.com Records when the GPU context for the MirroringGpuFactoriesFactory instance is lost. This should prompt a renegotiation without that hardware encoder configuration being offered. jophba@chromium.org openscreen-eng@google.com Records errors encountered by the Mirroring Service. If an error occurs while media remoting, the service attempts to revert to mirroring. Otherwise mirroring is terminated. jophba@chromium.org openscreen-eng@google.com The type of Presentation URL used in a PresentationRequest by a web page. jophba@chromium.org openscreen-eng@google.com Logged when the Media Router starts a presentation according to the type of presentation URL and the type of media sink. Warning: this histogram was expired from 2025-08-31 to 2026-02-02; data may be missing. jophba@chromium.org openscreen-eng@google.com Result of a request to a MediaRouteProvider to create a route. CreateRoute.Result (without a suffix) is recorded for the extension or an unknown MRP. {MediaRouteProvider} jophba@chromium.org openscreen-eng@google.com Result of a request to a MediaRouteProvider to join a route. JoinRoute.Result (without a suffix) is recorded for the extension or an unknown MRP. {MediaRouteProvider} jophba@chromium.org openscreen-eng@google.com Result of a request to a MediaRouteProvider to terminate a route. TerminateRoute.Result (without a suffix) is recorded for the extension or an unknown MRP. {MediaRouteProvider} jophba@chromium.org openscreen-eng@google.com The type of the Media Sink that media is being cast to. Recorded each time the user selects a Media Sink to start casting. Recorded for all the UI entry points. jophba@chromium.org openscreen-eng@google.com The type of the Media Sink that media is being cast to. Recorded each time the user selects a Media Sink to start casting from {Ui}. jophba@chromium.org openscreen-eng@google.com The source of a Media Router session. This is recorded to keep track of what kind of media is being streamed. jophba@chromium.org openscreen-eng@google.com A Mediarouter dialog can be two types: (1) A route controller dialog where users can stop casting. (2) A device picker where users can select a device and cast to it. This histogram records when users interact with the dialog (start or stop casting). jophba@chromium.org openscreen-eng@google.com A MediaRouter dialog is opened when users click on the Cast buttons supplied by the Cast SDK or the default HTML media player. This histogram records the type of the dialog when the dialog is created. jophba@chromium.org openscreen-eng@google.com Counts the number of devices known and populated to the Media Router dialog (or the Global Media Controls' device picker) three seconds after the dialog loads. Always expected to be non-negative. This includes data recorded from Clank, which uses Android's MediaRouter framework. jophba@chromium.org openscreen-eng@google.com This records how the Cast dialog was opened and what Cast mode was used whenever a Cast session starts. jophba@chromium.org openscreen-eng@google.com Whether the Cast toolbar icon is in its ephemeral state (shown only when the feature is active), or is pinned to the toolbar by user pref / admin policy. jophba@chromium.org openscreen-eng@google.com Recorded when the permission rejected error is shown in the Cast/Gmc dialog and when users click on the system settings link in the error message. jophba@chromium.org openscreen-eng@google.com Duration in milliseconds taken from the user click to open the {DialogType} dialog to show available devices. Recorded only when there are discovered devices shown in the dialog. jophba@chromium.org openscreen-eng@google.com The number of Media Sinks available for Casting a Presentation API URL to local screens. Recorded at most once an hour, when the Wired Display Media Route Provider reports an update on the sink count.