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Re: SDP renegotiation with same msid but different ssrc (video becomes frozen)

From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Sat, 16 Apr 2016 13:25:40 +0200
Message-ID: <CALiegfm_p=UwWCf16Gi7rJC18gOHbG2O0QKW8XFnagsr_d1ymw@mail.gmail.com>
To: Randell Jesup <randell-ietf@jesup.org>
Cc: "public-webrtc@w3.org" <public-webrtc@w3.org>
2016-04-15 16:26 GMT+02:00 Randell Jesup <randell-ietf@jesup.org>:
> On 4/15/2016 7:33 AM, Iñaki Baz Castillo wrote:
>> 2016-04-14 20:45 GMT+02:00 Cullen Jennings <fluffy@iii.ca>:
>>> The sender can change the SSRC whenever it becomes aware of a SSRC
>>> collisions and the receiver has to deal with that. It's one of the many
>>> reasons for use of identifiers other than SSRC (like rid)
>> SSRC is a 32 bit long integer. There are no SSRC collisions. And if
>> there were, there could also be RID or MID collisions.
> SSRC collisions happen in real life.  Some devices like to use non-random
> SSRCs (0 is a good value, right? Or 1? ;-)  ), and they can end up
> colliding.  Or they seed poorly.  Or just bad luck.

If a device uses a fixed SSRC with value 0 or 1 I would not expect
that it will implement RID or MID. And if it did that, it would set ""
for both values XD

BTW: If an endpoint decides to change a SSRC, is a SDP re-offer needed
by indicating the new SSRC in use? (regardless it is not needed if
RID/MID is in use and so on...).

Iñaki Baz Castillo
Received on Saturday, 16 April 2016 11:26:28 UTC

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