RE: Is sending multiple audio codecs on same RTCRtpSender supported?

There are several potential scenarios: 

1. Switching between Opus and PCMA.  This is accomplished by including both Opus and PCMA in the codecs[] sequence, and changing the order to switch between one and the other. 
This is supported in both WebRTC 1.0 and ORTC, and has been implemented in Edge and ORTC Lib. 

2. Utilizing RED to encapsulate both Opus and PCMA.  This is also possible in both WebRTC 1.0 and ORTC.  Currently I believe this is accomplished by including RED, Opus and PCMA in the codecs[] sequence (in that order?), then setting parameters.encodings[].fec.method to "red".  This is supported in Edge (and ORTC lib?)

3. Attempting to send both Opus and PCMA simultaneously.  In theory, this should be supportable in WebRTC 1.0 (and ORTC) using simulcast and RIDs.  In practice,  we do not support this in Edge (only the first codec in the codecs[] sequence will be sent). 
________________________________________
From: Sergio Garcia Murillo [sergio.garcia.murillo@gmail.com]
Sent: Friday, April 15, 2016 12:49 PM
To: public-ortc@w3.org
Subject: Is sending multiple audio codecs on same RTCRtpSender supported?

Hi all,

Imagine the following (crazy) scenario, where you want to send OPUS and PCMA on the same RTCRtpSender (obviously on different ssrcs as they have different clock rates).

Is it assumed that this SHALL be supported by all browsers implementing ORTC?

I think we should explicitly set it in the spec if this shall be supported or it is forbidden. If I have this kind of doubt in the SDP O/A world I have tons of RFCs I can search for the answer, but with the ortc params there is no other source of information I can look for.

Best regards
Sergio

Received on Saturday, 16 April 2016 13:32:51 UTC