Re: [webrtc-pc] Should the remote track mute in response to replaceTrack(null)? (#3077)

> The timeouts—15s for audio and 3s for video ([5 and 1](https://searchfox.org/firefox-main/search?q=rtcp_report_interval_ms&redirect=false) x [3](https://searchfox.org/firefox-main/rev/6f3037f71baa242161ed343cdccb12c1b8e50227/third_party/libwebrtc/modules/rtp_rtcp/source/rtcp_receiver.cc#81,96,98,100))—are RTCP timeouts, not RTP timeouts, so replaceTrack(null) doesn't cause timeout.

That's a good nuance to highlight, still seems a bit aggressive...

I assume that an inactive m= section does not send RTCP either. Not sure about inactive, but probably not?

For inspiration, here's how we talk about SSRC lifetimes in getStats, which should reflect what SSRCs are configured by WebRTC at the time getStats is called... when do delete SSRCs:

> RTP monitored objects are deleted when the corresponding RTP sender or RTP receiver is reconfigured to remove the corresponding RTP stream. This happens for the old SSRC when the [ssrc](https://w3c.github.io/webrtc-stats/#dom-rtcrtpstreamstats-ssrc) changes, a simulcast layer is dropped or the [RTCRtpTransceiver](https://www.w3.org/TR/webrtc/#dom-rtcrtptransceiver)'s [currentDirection](https://www.w3.org/TR/webrtc/#dom-rtcrtptransceiver-currentdirection) becomes "stopped". **The monitored object is not deleted if the transceiver is made "inactive" or if the encoding's [active](https://www.w3.org/TR/webrtc/#dom-rtcrtpencodingparameters-active) parameter is set to false.** If an SSRC is recycled after a deletion event has happened, this is considered a new RTP monitored object and the new RTP stream stats will have reset counters and a new ID.

This does not mention RTCP timeout and the fact that we don't see inbound-rtp sporadically disappearing suggests that RTCP timeout isn't implemented. I'd say from a stats point of view that's a good thing, it would be problematic if we systematically cleared stats during periods of the calls that were problematic and had freezes, that's data you would want to include in the report. So I think mute/unmute should not pretend SSRCs goes away here either

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Received on Friday, 3 October 2025 07:00:54 UTC