Re: [rtcweb] A proposal for FEC

[Magnus Westerlund <[e-mail]>]

On 2014-05-19 11:58, Bernard Aboba wrote:
>>
>> On May 19, 2014, at 11:33 AM, Magnus Westerlund <[e-mail]> wrote:
>>
>> I think adding ULPFEC in WebRTC is reasonable, however despite what RFC
>> 5956 says, we do have a spec issue with the following part of RFC 5109
>> that will be required to be overridden:
>>
>> Section 7.2:
>>
>>   Synchronization Source (SSRC): The SSRC value SHALL be the same as
>>   the SSRC value of the media stream it protects.
>>
>> Section 14.1:
>>
>>   The SSRC of the FEC stream MUST
>>   be set to that of the protected payload stream.
>>
>>   So the FEC
>>   stream and the payload stream SHOULD be sent through two separate RTP
>>   session, and multiplexing them by payload type into one single RTP
>>   session SHOULD be avoided.  In addition, the FEC and the payload MUST
>>   NOT be multiplexed by SSRC into one single RTP session since they
>>   always have the same SSRC.
>>
>>> From my perspective this override should be done in a separate document
>> so that also others can use it and not being RTCWEB specific.
> 
> The following draft accomplishes this, no?
> http://tools.ietf.org/html/draft-lennox-payload-ulp-ssrc-mux
> 

Yes, but it needs some updates and polishing before ready for
publication. Also, it has not been adopted yet in any WG. But, I think
adopting it and getting it moved forward in an expedited fashion would
be the right way forward.

Cheers

Magnus Westerlund

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