RTCOutboundRtpStreamStats: ssrc property

Baseline Widely available

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

The ssrc property of the RTCOutboundRtpStreamStats dictionary contains a positive integer value that identifies the synchronization source (SSRC) of this stream of RTP packets.

A source might be something like a microphone, or a mixer application that combines multiple sources. All packets from the same source share the same time source and sequence space, and so can be ordered relative to each other. Note that two streams with the same ssrc value refer to the same source.

Value

A positive 32-bit integer uniquely identifying the SSRC of the RTP packets whose statistics are covered by this RTCOutboundRtpStreamStats object.

The manner in which SSRC values are generated is not mandated by the specification, although it does make recommendations. You should not make any assumptions based on the value of ssrc other than that any two objects with the same ssrc value refer to the same source. See RFC 3550, section 8 for additional information about ssrc.

Note: The specification includes an example that generates values for ssrc using MD5. While not part of the standard, exactly, it is a good mechanism that may be used by some browsers; others may use other methods, such as random number generators. Do not rely upon these values meaning anything other than "these objects are associated with the same source."

Specifications

Specification
Identifiers for WebRTC's Statistics API
# dom-rtcrtpstreamstats-ssrc

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
ssrc in 'outbound-rtp' stats
Chrome – Full support
Chrome 80 (Release date: 2020-02-04)
footnote Full support
Edge – Full support
Edge 80 (Release date: 2020-02-07)
footnote Full support
Firefox – Full support
Firefox 27 (Release date: 2014-02-04)
footnote Full support
Opera – Full support
Opera 67 (Release date: 2020-03-03)
footnote Full support
Safari – Full support
Safari 11 (Release date: 2017-09-19)
footnote Full support
Chrome Android – Full support
Chrome Android 80 (Release date: 2020-02-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 27 (Release date: 2014-02-04)
footnote Full support
Opera Android – Full support
Opera Android 57 (Release date: 2020-03-30)
footnote Full support
Safari on iOS – Full support
Safari on iOS 11 (Release date: 2017-09-19)
footnote Full support
Samsung Internet – Full support
Samsung Internet 13 (Release date: 2020-12-02)
footnote Full support
WebView Android – Full support
WebView Android 80 (Release date: 2020-02-04)
footnote Full support
WebView on iOS – Full support
WebView on iOS 11 (Release date: 2017-09-19)
footnote Full support

Legend

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

Full support
Full support

See also