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Re: [rtcweb] Plan A, respun

Emil Ivov <emcho@jitsi.org> Mon, 20 May 2013 10:08 UTC

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Date: Mon, 20 May 2013 13:08:20 +0300
From: Emil Ivov <emcho@jitsi.org>
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To: Adam Roach <adam@nostrum.com>
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Subject: Re: [rtcweb] Plan A, respun
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On 20.05.13, 12:46, Adam Roach wrote:
> On 5/18/13 00:02, Emil Ivov wrote:
>>
>> On 17.05.13, 18:08, Eric Rescorla wrote:
>>> On Fri, May 17, 2013 at 8:00 AM, Emil Ivov <emcho@jitsi.org
>>> <mailto:emcho@jitsi.org>> wrote:
>>>
>>>
>>>      On 17.05.13, 16:07, Eric Rescorla wrote:=line.
>>>
>>>
>>>      > then presumably you need to follow this rule to ensure interop, no?
>>>
>>>      Therefore, the interop part with the "many" endpoints seems to be
>>>      covered already. One still needs to find ways of handling and
>>>      potentially gatewaying ICE and SRTP for many of them but that's a
>>>      different matter. O/A-wise we seem to have consensus on how to do the
>>>      case with the two m= lines that each carry one track.
>>>
>>>      It seems to me that we have now moved beyond that.
>>>
>>>
>>> The question is how an endpoint which wishes fo offer more than one
>>> audio and one video does so in a way that doesn't cause older
>>> endpoints to choke.
>> I might be misunderstanding or missing something, but isn't it clear
>> that, if you are trying not to choke anyone, the first thing to do would
>> be to stick to a single m= line for audio and a single m= line for video?
>>
> 
> Not if you're talking to a device that expects three media streams -- 

This gets back to my original point: I don't see how such a device would
qualify as one of the "many legacy endpoints that have already been
deployed".

> such things have historically used three m=video sections (one for each 
> stream). Which is kind of the reason we're specifying Plan A the way we are.

I get that, but I don't believe it is an effort to guarantee interop
with legacy. It's an effort to talk to specific applications that use
such signalling.

Note that if you really need to interoperate with such applications you
would still be able to do this if WebRTC gave you the necessary API.
You would then have the choice of modifying the browser's SDP in the
javascript or handling it all in a signalling gateway.

Emil

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