Re: [webrtc-pc] `ssrc` in `RTCRtpEncodingParameters` is inconsistent with ORTC (#1174)

@murillo128 SSRCs were formerly provided in `RTCRtpEncodingParameters`, as read-only parameters, along with `rid`.  The question arose as to what would happen in the situation where `ssrc` changed in between `get` and `setParameters`.  This didn't seem intractable (one option is to ignore the attempt to set `ssrc`, rather than error), but Taylor's take was it would be easier to include SSRCs in the Unified Plan SDP for simulcast, similar to how it was done for non-simulcast scenarios. However, this did not take into account the need to relate RIDs and SSRCs in SDP, something which the object model addressed.  Can you describe the scenario for needing to relate them?

@amithilbuch  If SSRCs are not provided in the object model or in the SDP, how is a simulcast application to obtain SSRCs in order to signal to a legacy SFU?  Not sure what you mean by "SDP munging" in that scenario. 

@fippo One potential impact of removing SSRC info is the effect on simulcast loopback testing in WPT (e.g. "simulcast playground").  It's not possible to build "simulcast playground" with MIDs or RIDs alone, right? 

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Received on Friday, 1 March 2019 04:38:42 UTC