W3C home > Mailing lists > Public > public-media-capture@w3.org > April 2014

Re: Screen sharing

From: Cullen Jennings (fluffy) <fluffy@cisco.com>
Date: Sun, 27 Apr 2014 19:41:35 +0000
To: Harald Tveit Alvestrand <harald@alvestrand.no>
CC: Martin Thomson <martin.thomson@gmail.com>, "public-media-capture@w3.org" <public-media-capture@w3.org>
Message-ID: <CDDBF6E5-9A9B-46BE-84E0-F7ADB64C5B52@cisco.com>

On Apr 25, 2014, at 12:33 PM, Harald Alvestrand <harald@alvestrand.no> wrote:

> On 04/25/2014 06:51 PM, Martin Thomson wrote:
>> On 25 April 2014 00:09, Harald Alvestrand <harald@alvestrand.no> wrote:
>>> I'd suggest that this is actually more useful, and what we should say that
>>> "application" source is intended to be, but might have to carry the caveat
>>> that "some applications, some of the time, wil be unable to present screen
>>> content that is not also shown on the user's screen - this will lead to
>>> parts of the image being frozen or greyed-out".
>> This ignores the potential issues that this presents.  If I'm sharing
>> an app and there were things that my peer sees without my knowledge,
>> that could be problematic.  I don't know what the right answer is, but
>> it isn't as simple as you claim.
> I don't claim that it's simple, but that it's useful. (at the moment, the tab-casting feature of my Chromecast dongle lets me play Spotify on my TV while I'm doing other things on the screen).
> Yes, screen capture of pop-unders is a real issue. We might have to limit such functionality to "applications" that are part of the Web model, where one can either use the same-origin criterion or use CORS to get authorization.
> I'm not sure what the answers should be, but "you can only send what's on the screen" seems like it's not a complete answer either.

Iíve been in lots of conversation about if, when doing application sharing, if it is better to show the hidden content or not. It seems that the argument that usual wins out is that itís just too surprising for users when stuff the user can not see themselves gets shared with the far side. Perhaps the answer is different for tab sharing where the app might be designed more with that in mind. I do realize that in some cases, you want to share the hidden stuff. 

On another note, Iíve seen a lot of problem of actually trying to get the hidden rendered content on some OS particularly when using graphics cards with lots of hardware acceleration for open GL and such. Some of the cards seem to manage to optimize away the rendering of hidden area then it does not share correctly. 
Received on Sunday, 27 April 2014 19:42:03 UTC

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