RTCAudioSourceStats
The WebRTC API's RTCAudioSourceStats
dictionary provides information about an audio track that is attached to one or more senders.
These statistics can be obtained by iterating the RTCStatsReport
returned by RTCRtpSender.getStats()
or RTCPeerConnection.getStats()
until you find a report with the type
of media-source
and a kind
of audio
.
Note: For audio information about remotely sourced tracks (that are being received), see RTCInboundRtpStreamStats
.
Instance properties
audioLevel
Experimental-
A number that represents the audio level of the media source.
totalAudioEnergy
Experimental-
A number that represents the total audio energy of the media source over the lifetime of the stats object.
totalSamplesDuration
Experimental-
A number that represents the total duration of all samples produced by the media source over the lifetime of the stats object.
The following properties are present in both RTCAudioSourceStats
and RTCVideoSourceStats
:
trackIdentifier
-
A string that contains the
id
value of theMediaStreamTrack
associated with the audio source. kind
-
A string indicating whether this object represents stats for a video source or a media source. For an
RTCAudioSourceStats
this will always beaudio
.
Common instance properties
The following properties are common to all statistics objects.
id
-
A string that uniquely identifies the object that is being monitored to produce this set of statistics.
timestamp
-
A
DOMHighResTimeStamp
object indicating the time at which the sample was taken for this statistics object. type
-
A string with the value
"media-source"
, indicating that the object is an instance of eitherRTCAudioSourceStats
orRTCVideoSourceStats
.
Description
The interface provides statistics about an audio media source attached to one or more senders. The information includes the current audio level, averaged over a short (implementation dependent) duration.
The statistics also include the accumulated total energy and total sample duration, at a particular timestamp.
The totals can be used to determine the average audio level over the lifetime of the stats object.
You can calculate a root mean square (RMS) value in the same units as audioLevel
using the following formula:
You can also use the accumulated totals to calculate the average audio level over an arbitrary time period.
The total audio energy of the stats object is accumulated by adding the energy of every sample over the lifetime of the stats object, while the total duration is accumulated by adding the duration of each sample.
The energy of each sample is determined using the following formula, where sample_level
is the level of the sample, max_level
is the highest-intensity encodable value, and duration
is the duration of the sample in seconds:
The average audio level between any two different getStats()
calls, over any duration, can be calculated using the following equation:
Examples
This example shows how you might iterate the stats object returned from RTCRtpSender.getStats()
to get the audio source stats, and then extract the audioLevel
.
js
// where sender is an RTCRtpSender
const stats = await sender.getStats();
let audioSourceStats = null;
stats.forEach((report) => {
if (report.type === "media-source" && report.kind==="audio") {
audioSourceStats = report;
break;
}
});
const audioLevel = audioSourceStats?.audioLevel;
Specifications
Specification |
---|
Identifiers for WebRTC's Statistics API # dom-rtcstatstype-media-source |
Browser compatibility
BCD tables only load in the browser