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

Harald Alvestrand <> Mon, 19 September 2011 07:26 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 06EBF21F8560 for <>; Mon, 19 Sep 2011 00:26:39 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -108.185
X-Spam-Status: No, score=-108.185 tagged_above=-999 required=5 tests=[AWL=2.414, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8, USER_IN_WHITELIST=-100]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id wnCASRT3BeDn for <>; Mon, 19 Sep 2011 00:26:38 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 22D5921F852E for <>; Mon, 19 Sep 2011 00:26:38 -0700 (PDT)
Received: from localhost (localhost []) by (Postfix) with ESMTP id CCF9339E0CD; Mon, 19 Sep 2011 09:28:59 +0200 (CEST)
X-Virus-Scanned: Debian amavisd-new at
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id mNvhpkvvdKDK; Mon, 19 Sep 2011 09:28:59 +0200 (CEST)
Received: from [] ( []) by (Postfix) with ESMTPS id 425F139E051; Mon, 19 Sep 2011 09:28:59 +0200 (CEST)
Message-ID: <>
Date: Mon, 19 Sep 2011 09:28:58 +0200
From: Harald Alvestrand <>
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20110831 Thunderbird/3.1.13
MIME-Version: 1.0
To: Magnus Westerlund <>
References: <>
In-Reply-To: <>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 8bit
Cc: "" <>
Subject: Re: [rtcweb] Call for Consensus on Use Case for Screen/Application/Desktop sharing
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 19 Sep 2011 07:26:39 -0000

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 
> 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:
> ----------------------------------------------------------------------
> _______________________________________________
> rtcweb mailing list