Re: [rtcweb] Call for Consensus on Use Case for Screen/Application/Desktop sharing

Harald Alvestrand <harald@alvestrand.no> Mon, 19 September 2011 07:26 UTC

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Date: Mon, 19 Sep 2011 09:28:58 +0200
From: Harald Alvestrand <harald@alvestrand.no>
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To: Magnus Westerlund <magnus.westerlund@ericsson.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] Call for Consensus on Use Case for Screen/Application/Desktop sharing
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On 09/19/2011 09:02 AM, Magnus Westerlund wrote:
> WG,
>
> There where some discussion in the Interim meeting last week about a
> Screen/Application/Desktop sharing support use case. My take away from
> the discussion is that this use cases is likely well enough understood
> to actually start a consensus call now. However, to us WG chairs it was
> clear that the use case in question actually needs to be split into two
> parts.
>
> A) Where the RTCWEB enabled browser can use a local application window,
> the whole desktop or a Screen as a media source that can be encoded and
> transported over the peerConnection for displaying/playback at the peer.
I think this is a fairly well defined applicaiton (basically, take input 
from a synthetic source, where the synthetic source may be anything 
available to the browser), the baseline (but not the optimum) could 
simply be encoding the stuff using a default codec, and the access 
procedures shouldn't be much different than for microphone and camera. I 
support its inclusion in the document.

Note: The implementation of such a feature is far from trivial. I would 
not want to require that all browsers implementing RTCWeb support the 
feature.
> B) Where a remote peer can provide one or more input types such as mouse
> and keyboard to control the local system, not only including the
> browser, but also other operating system resources. This clearly can
> only happen after additional consent, most likely on a per occasion
> consent.
I see this as a  more tricky thing to get right (in most apps, the 
mixing of events from multiple sources depends strongly on both proper 
timing/sequencing and reliable delivery). I would like to not address 
this for now (RTCWeb version 1).
> My interpretation is that A only allows for application sharing in
> conferencing contexts, like in the WEBEX session the Interim meeting was
> held with where we shared slides. Where the combination of A and B is
> providing for VNC/Remote desktop.
>
> Thus the question to the WG is the following.
>
> 1) Do you support or object the inclusion of use case A, B or Both in
> our Use case document?
>
> 2) Do you have additional comments for or against either of the use cases?
>
>
> As WG chair
>
> Magnus Westerlund
>
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVM
> ----------------------------------------------------------------------
> Ericsson AB                | Phone  +46 10 7148287
> Färögatan 6                | Mobile +46 73 0949079
> SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
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