Re: [rtcweb] WG Last Call: draft-ietf-rtcweb-use-cases-and-requirements-10

On 2013-01-18 17:06, Magnus Westerlund wrote:
> WG,
>
> I would here by like to announce a two week WG last call that ends on
> the 1st of February.
>
> Document is available here:
>
> https://datatracker.ietf.org/doc/draft-ietf-rtcweb-use-cases-and-requirements/

As discussed in an earlier thread, I think that it should be clarified 
how the streams for the small/big video displays in use-case 4.3.3 are 
generated.

To recap, the use case is about a multiparty video (and audio of course) 
communication session using a central node.

At the screen of each endpoint/user, one video is displayed on a large 
surface, with other videos are shown as (live) thumbnails.

Which video to show at the large display surface is depending on speech 
activity; the video form the endpoint with currently talking user(s) is 
shown on the large surface - and this will usually change frequently 
during the session. This selection is handled by the central node which 
has access to all video and audio streams.

I think this is a quite common model, used by many services.

The current draft list three ways to support this use-case (use scalable 
video codecs, transcode in the central node, or use simulcast), but 
there are no requirements that back this up.

We should pick one solution that must be supported, and then derive the 
corresponding requirements.

As said before, I am a proponent for simulcast as solution to this use-case.

Stefan
>
> Cheers
>
> Magnus Westerlund
>
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