The read-only source property of the RTCRtpContributingSource interface returns the source identifier of a particular stream of RTP packets. The value is the contributing source (CSRC) or synchronization source (SSRC) identifier, depending on whether the object is an RTCRtpContributingSource or RTCRtpSynchronizationSource, which is based on the former.


var sourceID = RTCRtpContributingSource.source


An unsigned, 32-bit integer value which uniquely identifies the source of RTP packets described by this RTCRtpContributingSource (in which case the value is a CSRC identifier) or RTCRtpSynchronizationSource (the value is an SSRC identifier).


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'source' in that specification.
Candidate Recommendation Initial definition.

Browser Compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support59 ?591 No No ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support5959 ?591 No ?7.0

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.

Document Tags and Contributors

Contributors to this page: fscholz, Sheppy, jpmedley
Last updated by: fscholz,