[rtcweb] Support for RFC7728 pause indication

[Sergio Garcia Murillo <[e-mail]>]

Hi all,

According to the rtp usage draft, it is allowed to pause and resume 
transmissions at any time. There are several scenarios in which it would 
make sense to signal when a webrtc sender decides to pause one stream to 
the receiving side.

One of them, (as described in detail in 
https://monorail-prod.appspot.com/p/webrtc/issues/detail?id=5207) is be 
when the webrtc endpoints decides to stop sending one simulcast stream 
in order to adapt the sent bandwidth to the bandwidth estimation. In 
that case the SFU would benefit from having that indication before 
having to wait for a timeout on media reception before switching to a 
different simulcast stream. Note that in this case, the stream is paused 
from inside the webrtc stack, so there is no event triggered to be able 
to signal this to the js app so it could notify it off band to the 
receiving side.

 From the solutions discussed, IMHO, the cleanest one would be to 
support the PAUSE indication from RFC7728. Do you think it could be 
considered to support it in webrtc?

Best regards

Sergio