Re: An idea for specifying RTX, FEC, and RED payload types

Hi Peter,

While it is not very common to have RTX and FEC enabled simultaneously, 
in theory I think it could be possible to have an RTX stream for the 
RED/FEC payload. With your approach that would not be possible, as FEC 
would not be a codec. It is a restriction I could live with, but we 
should make it clear stated.

Best regards
Sergio
On 17/10/2014 19:54, Peter Thatcher wrote:
> They aren't real codecs, so it's kind of ugly going in "codecs", and 
> it isn't completely obvious that doing so is necessary.  It's also not 
> obvious to use "APT" in an RTX "codec", not to mention that it's also 
> kind of ugly.
>
> So, perhaps we could do something like this:
>
> dictionary RTCRtpParameters {
>    DOMString                       muxId = "";
>    sequence<RTCRtpCodecParameters> codecs;
> *   payloadtype                     redPayloadType;
>    payloadtype                     fecPayloadType;*
>    ...
> };
>
> dictionary RTCRtpCodecParameters {
>    DOMString   name;
>    payloadtype payloadType;
> *   payloadtype rtxPayloadType;*
>    ...
> };
>
> ​
> Note that this does not tell the browser to send RTX, FEC, or RED.  To 
> do so, one must put in the correct per-encoding control points under 
> RtpEncodingParameters.  This merely specifies the payload types to 
> send or receive
> ​ in a way that's a little cleaner and more obvious than putting them 
> in the list of RtpCodecParameters.​
>
>
> Thoughts? ​
> ​