On Thu, Mar 5, 2015 at 9:46 AM, <[email protected]> wrote:

> On Thursday, March 5, 2015 at 3:32:46 PM UTC, Eric Rescorla wrote:
> > This isn't going to work very well, with any version of Firefox.
> >
> > The semantics of this SDP is that you are offering a bunch of audio
> > streams, and that each of them is (for some unknown reason) with
> > a different codec.
> >
> > Firefox prior to 37 only supports one audio stream so it will try to
> > accept the first audio line, but will discover that it doesn't have
> > a compatible codec, so the negotiation will fail.
> >
> > Firefox after 37 will accept multiple audio streams, but will accept
> > *every* stream with a compatible codec, so in this case it would
> > probably accept PCMU and PCMA, with the result that you get
> > multiple incoming audio lines with (presumably) the same content.
> >
> > I also note that you haven't supplied any a=fingerprint lines which
> > are required for DTLS-SRTP but instead are supplying a=crypto
> > lines for SDES. This isn't compliant with the specification and Firefox
> > won't accept it, as will Chrome sometime in the future.
> >
> > -Ekr
> >
> >
> >
> >
> >
> >
> > On Thu, Mar 5, 2015 at 6:13 AM, <[email protected]> wrote:
> >
> > > I used Firefox 33.1, with JsSIP and Kamailio, with a call to our
> desktop
> > > video-conferencing application running on Windows. We were assessing
> > > interoperability between the audio and video codecs. Our application
> sent
> > > SDP with one media line per payload, rather than one media line
> containing
> > > a list of payload numbers, like this (simplified version):
> > >
> > > m=audio <port> RTP/SAVPF <payload-1>
> > > a=rtcp ...
> > > a=rtpmap:<payload-1> X-G72x1
> > > a=ice...
> > > a=crypto...
> > > a=candidate...
> > > a=candidate...
> > > m=audio <port> RTP/SAVPF <payload-2>
> > > a=rtcp ...
> > > a=rtpmap:<payload-2> PCMA
> > > a=ice...
> > > a=crypto...
> > > a=candidate...
> > > a=candidate...
> > > m=audio <port> RTP/SAVPF <payload-3>
> > > a=rtcp ...
> > > a=rtpmap:<payload-3> PCMU
> > > a=ice...
> > > a=crypto...
> > > a=candidate...
> > > a=candidate...
> > >
> > > In the SIP INVITE, our application happened to have X-G72x1 as the
> first
> > > audio codec in the SDP, which I believe is not supported by firefox,
> and
> > > the call was rejected. My thoughts are that perhaps firefox is only
> > > expecting one m=audio, rather than multiple, and since the one at the
> top
> > > is an unsupported codec, it rejects it. Our application also listed
> PCMU
> > > and PCMA in following media lines, but perhaps these are simply
> ignored?
> > > _______________________________________________
> > > dev-media mailing list
> > > [email protected]
> > > https://lists.mozilla.org/listinfo/dev-media
> > >
>
> Many thanks for your reply. We do have fingerprint lines, I just hadn't
> included them in my blob - can I ask when will SDES support be removed?
>

I do not know when Chrome will remove them. Firefox has never supported
SDES.



> So, just to clarify, firefox after 37 will interpret multiple audio m
> lines as a request to supply multiple streams?


Yes, provided that they are otherwise correct.

-Ekr
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