[ortc] Clarification on encodings codecPayloadType for RTCRtpSender

murillo128 has just created a new issue for 
https://github.com/openpeer/ortc:

== Clarification on encodings codecPayloadType for RTCRtpSender ==
It is not explicitly said nowhere in the specification, but I assume 
that encodings only make sense for media codecs. That is, for 
non-media codecs [CN,dtmf, RED and FEC] there is no sense of adding 
them in the encodings and will be used as follow:

-DTMF present in codecs only means that if can create a RTCDtmfSender 
for that sender and it will have the canInsertDTMF to true, and false 
if not present.
-RED will be used whenever an encoding has a fec.mechanishm of "red" 
or "red-ulpfec", and will not be used in an other case. It is 
ssrc-dependant so if an RTCRtpSender has two encodings with different 
ssrcs one with fec="red" and the other without it, it will only be 
used on the former one. 
-FEC same as RED but on mechanishm = "red-ulpfec" or "flexfec". 
-CN it will be used to send a comfort noise packets in case no voice 
is detected on track, on all ssrc streams.

RTX is a different kind and there are already other issues handling 
it.

So, I would recommend to add something like:

> RTCRtpSender will ignore any encoding containing a codecPayloadType 
which references a non-media codec ("cn", "dtmf", "red", "rtx", or a 
forward error correction codec).

Please view or discuss this issue at 
https://github.com/openpeer/ortc/issues/470 using your GitHub account

Received on Friday, 15 April 2016 19:26:40 UTC