advertising XR support?

[robin-raymond]

https://tools.ietf.org/html/rfc3611#section-5.1

rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF

     xr-format = pkt-loss-rle
               / pkt-dup-rle
               / pkt-rcpt-times
               / rcvr-rtt
               / stat-summary
               / voip-metrics
               / format-ext

How do we advertise support for various RTCP control messages that are supported? Example XR blocks?

[robin-raymond]

This could operate just like RTCRtcpFeedback:

dictionary RTCRtcpFeedback {
             DOMString type;
             DOMString parameter;
};

Except instead of advertising supported feedback mechanisms, we could add something to advertise each combination of RTCP control messages that are supported, eg.:

dictionary RTCRtcpControlMechanism {
             DOMString type;
             DOMString parameter;
};

And we need to put as both a capability and a setting:

In the capabilities:

dictionary RTCRtpCapabilities {
             sequence<RTCRtpCodecCapability>        codecs;
             sequence<RTCRtpHeaderExtension>        headerExtensions;
             sequence<DOMString>                    fecMechanisms;
             sequence<RTCRtcpControlMechanism>      controlMechanisms;
};

[robin-raymond]

And as a setting inside the RTCP parameters:

dictionary RTCRtcpParameters {
             unsigned long        ssrc;
             DOMString            cname;
             boolean              reducedSize = false;
             boolean              mux = true;
             sequence< RTCRtcpControlMechanism >  controlMechanisms;
};

[aboba]

XR block support is relevant to the WebRTC Stats API, not ORTC, since there are no ORTC parameters that are influenced by whether an implementation supports a partial XR block specification or not.

So I do not believe that this is an ORTC API Issue.