The getSynchronizationSources() method of the RTCRtpReceiver interface returns an array of RTCRtpContributingSource instances, each corresponding to one SSRC (synchronization source) identifier received by the current RTCRtpReceiver in the last ten seconds.
Syntax
var rtcRtpContributingSources = rtcRtpReceiver.getContributingSources()
Parameters
None.
Return value
An array of RTCRtpSynchronizationSource instances. Each instance describes one of the synchronization sources that provided data to the incoming stream in the past ten seconds.
As you'll see in the documentarion for RTCRtpSynchronizationSource, it inherits the properties of RTCRtpContributingSource, including timestamp, source, and audioLevel.
The synchronization source objects add a voiceActivityFlag property, which indicates if the last RTP packet received contained voice activity.
Specifications
| Specification | Status | Comment |
|---|---|---|
| WebRTC 1.0: Real-time Communication Between Browsers The definition of 'getSynchronizationSources()' in that specification. |
Candidate Recommendation | Initial definition. |
Browser compatibility
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | No | ? | 59 | ? | No | ? |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | No | No | ? | 591 | No | ? | No |
1. From version 59: this feature is behind the media.peerconnection.rtpsourcesapi.enable preference (needs to be set to true). To change preferences in Firefox, visit about:config.