RTCRtpReceiver: getSynchronizationSources() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

The getSynchronizationSources() method of the RTCRtpReceiver interface returns an array of objects, each corresponding to one SSRC (synchronization source) identifier received by the current RTCRtpReceiver in the last ten seconds.

Syntax

js
getSynchronizationSources()

Parameters

None.

Return value

An array of objects, each describing one of the synchronization sources that provided data to the incoming stream in the past ten seconds. These objects contain the following properties:

audioLevel

A floating-point value between 0.0 and 1.0 specifying the audio level contained in the last RTP packet played from the synchronization source.

The value is on a linear scale and is defined in units of dBov, or decibels (overload). This is the amplitude relative to the point at which clipping of the audio begins to occur. A value of 1.0 represents 0 dBov (maximum volume), a value of 0.0 represents silence, and a value of 0.5 represents approximately 6 dB SPL (decibels of sound pressure level) change in the sound pressure level from 0 dBov.

This value is required and always present.

rtpTimestamp Optional

The RTP timestamp (an integer DOMHighResTimeStamp) of the media. This source-generated timestamp indicates the time at which the media in this packet, scheduled for play out at the time indicated by timestamp, was initially sampled or generated. It may be useful for sequencing and synchronization purposes.

source Optional

A positive integer value specifying the SSRC identifier of the synchronization source. This uniquely identifies the source of the particular stream RTP packets.

timestamp Optional

A DOMHighResTimeStamp indicating the most recent time at which a frame originating from this source was delivered to the receiver's MediaStreamTrack

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-rtcrtpreceiver-getsynchronizationsources

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
getSynchronizationSources
Chrome – Full support
Chrome 73 (Release date: 2019-03-12)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 59 (Release date: 2018-03-13)
footnote Full support
Opera – Full support
Opera 60 (Release date: 2019-04-09)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 73 (Release date: 2019-03-12)
footnote Full support
Firefox for Android – Full support
Firefox for Android 59 (Release date: 2018-03-13)
footnote Full support
Opera Android – Full support
Opera Android 52 (Release date: 2019-05-17)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 11 (Release date: 2019-12-05)
footnote Full support
WebView Android – Full support
WebView Android 73 (Release date: 2019-03-12)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Audio tracks supported
Chrome – Full support
Chrome 73 (Release date: 2019-03-12)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 59 (Release date: 2018-03-13)
footnote Full support
Opera – Full support
Opera 60 (Release date: 2019-04-09)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 73 (Release date: 2019-03-12)
footnote Full support
Firefox for Android – Full support
Firefox for Android 59 (Release date: 2018-03-13)
footnote Full support
Opera Android – Full support
Opera Android 52 (Release date: 2019-05-17)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 11 (Release date: 2019-12-05)
footnote Full support
WebView Android – Full support
WebView Android 73 (Release date: 2019-03-12)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Video tracks supported
Chrome – Full support
Chrome 73 (Release date: 2019-03-12)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 68 (Release date: 2019-07-09)
footnote Full support
Opera – Full support
Opera 60 (Release date: 2019-04-09)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 73 (Release date: 2019-03-12)
footnote Full support
Firefox for Android – Full support
Firefox for Android 68 (Release date: 2019-07-09)
footnote Full support
Opera Android – Full support
Opera Android 52 (Release date: 2019-05-17)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 11 (Release date: 2019-12-05)
footnote Full support
WebView Android – Full support
WebView Android 73 (Release date: 2019-03-12)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support