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Re: Simulcast V1

From: Bernard Aboba <Bernard.Aboba@microsoft.com>
Date: Sat, 15 Aug 2015 16:56:43 +0000
To: Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>
CC: Adam Roach <abr@mozilla.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Message-ID: <9281E95C-D489-482C-82FE-784E8701CD25@microsoft.com>
On Aug 14, 2015, at 22:51, Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com> wrote:
> 
> Trying to get my head around it: would it be fair to say that the main 
> difference between Adam's proposal and track cloning relates to the 
> SDP produced by the browser? On the media plane it's the same (given 
> Bundle is used): the different simulcast streams travel on the same 
> ports with the same encodings etc.

[BA] The media would have similar transport characteristics and could be signaled on the wire in a similar way, but there is still the question of how to control characteristics of the simulcast streams being sent. In track cloning, constraints are used for this, in which characteristics of each track are individually specified.  In ORTC RtpEncodingParameters are used, which allows the relationship between the streams to be explicitly described (e.g. Low-res is 1/4 the resolution of hi-res).  Implementations of these control mechanisms could produce the same result with similar performance, but they might not.
Received on Saturday, 15 August 2015 16:57:14 UTC

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