jmelancongen
commented
2 weeks ago It's based on feedback from the F2F, not sure I remember who said it though. I'm not too worried about mentioning both as RFC 8834, which is a mandatory component of a WebRTC compliant media producer, already has a MUST for both of them. So we are only reiterating the need, but it is mandatory per WebRTC in any case.
FIR is a bit more proper when you have a SFU redirecting to multiple clients. A new client joining would trigger a FIR to signify that the i-frame request is more important for the experience. But I'm not feeling too strongly about it either way
This change adds a bit of text to solidify the requirement for device to handle the FIR & PLI messages, which request a new synchronisation point to the stream. In theory, WebRTC already requires that media producers implement those, so it is not really new, but we make it much clearer.
Those messages also do not absolutely force the production of an i-frame, as the device can use bandwidth requirements and other factors to decide if it should produce one, as specified in the linked RFCs