Re: [rtcweb] Reasons not to multiplex audio with video (Re: Fwd: I-D Action: draft-rosenberg-rtcweb-rtpmux-00.txt)

Jonathan Lennox <jonathan@vidyo.com> Mon, 25 July 2011 17:54 UTC

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From: Jonathan Lennox <jonathan@vidyo.com>
To: "Muthu Arul Mozhi Perumal (mperumal)" <mperumal@cisco.com>
Date: Mon, 25 Jul 2011 13:54:14 -0400
Thread-Topic: [rtcweb] Reasons not to multiplex audio with video (Re: Fwd: I-D Action: draft-rosenberg-rtcweb-rtpmux-00.txt)
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Subject: Re: [rtcweb] Reasons not to multiplex audio with video (Re: Fwd: I-D Action: draft-rosenberg-rtcweb-rtpmux-00.txt)
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On Jul 25, 2011, at 8:57 AM, Muthu Arul Mozhi Perumal (mperumal) wrote:

> A few options to indicate this multiplexing in SDP and being backward compatible with legacy implementations:


Unfortunately, I think the "correct" way to do this would be SDP media capability negotiation -- you'd offer an alternative of either two m= lines (one audio and one video), or else a single, mux'd m= line.  Anything else means that your SDP is, effectively, lying about what it's actually doing, and I'm really worried about how that would interact with other SDP extensions.

I'm certainly not crazy about this suggestion, though, because SDP Capability Negotiation is pretty ugly, and requires an additional offer/answer exchange to converge.

For RTCWeb proper, the need not to have worry about compatibility with legacy implementations means that much of this could potentially be avoided.

--
Jonathan Lennox
jonathan@vidyo.com