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Re: [rtcweb] Does RID require the same ext id for all the m= sections?

Iñaki Baz Castillo <ibc@aliax.net> Mon, 11 September 2017 12:49 UTC

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From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Mon, 11 Sep 2017 14:48:53 +0200
Message-ID: <CALiegf=6xRCXAx71XiErwqzwdVBVbFmzhvtaKS77v88Oh569TQ@mail.gmail.com>
To: "Mo Zanaty (mzanaty)" <mzanaty@cisco.com>
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Subject: Re: [rtcweb] Does RID require the same ext id for all the m= sections?
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On Sun, Sep 10, 2017 at 8:22 PM, Mo Zanaty (mzanaty) <mzanaty@cisco.com> wrote:
> All extmap IDs must be consistent in all bundled m= sections, just like PTs.

Thanks.

However, what does "consistent" mean? I assume/expect that the extmap
ID (for example a=extmap:4) cannot exist in two different m= sections
pointing to different extension URLs, right?

But, and given that you told about PTs, it's perfectly valid that two
different PTs point to the same codec+condiguration within the same m=
section or in different m= sections.

So, could a m=audio section have an "a=extmap:4 urn:foo" line while a
m=video section has "a=extmap:8 urn:foo"? or should both use extmap ID
4?

For example, the extmap ID for MID must be *UNIQUE* across all the
m=sections. Does the same constrain exist for the extmap ID for RID?



-- 
Iñaki Baz Castillo
<ibc@aliax.net>

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