Re: [MMUSIC] RID, MID and BUNDLE: Associate received RTP packet with m- line

Peter Thatcher <pthatcher@google.com> Thu, 22 October 2015 22:42 UTC

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From: Peter Thatcher <pthatcher@google.com>
Date: Thu, 22 Oct 2015 15:41:29 -0700
Message-ID: <CAJrXDUHfF_FYq1hmigr_xAFwqi612+Q3GKK8qo5AdbSQ=1uUYQ@mail.gmail.com>
To: Adam Roach <adam@nostrum.com>
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Cc: "mmusic@ietf.org" <mmusic@ietf.org>, Christer Holmberg <christer.holmberg@ericsson.com>
Subject: Re: [MMUSIC] RID, MID and BUNDLE: Associate received RTP packet with m- line
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And it's nice to have the same RIDs across multiple m-lines.  For example,
if each m-line represents a participant in a video  conference (say,
participants A, B, and C), and each has three RIDs (say, S, M, L) then you
can just have RID S, M, L on each m-line rather than having to have A-S,
A-M, A-L, B-S, B-M, B-L, C-S, C-M, C-L.

Of course, you can still do that if you want, but it may be inconvenient to
have to do it.

On Thu, Oct 22, 2015 at 12:21 PM, Adam Roach <adam@nostrum.com> wrote:

> On 10/22/15 2:18 PM, Christer Holmberg wrote:
>
> Hi,
>
>
>
> >RID (like MID and all SDES items) is limited to 255 octets. No risk of
> exhaustion, so offerers are free to make them >unique across the whole
> SDP if they want.
>
>
>
> If there is no risk of exhaustion, is there a reason not to MANDATE them
> to be unique?
>
>
> Well, it's an unnecessary restriction, and we'd like people to keep them
> short. While they won't be in every packet, they'll likely be in the *same*
> packets as other correlating identifiers like MID (e.g., at stream startup).
>
> On the balance, it's not much of a trade-off. The size of these things can
> still be pretty small if they're unique, but being unique buys you
> (almost?) nothing.
>
> /a
>
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