W3C home > Mailing lists > Public > public-media-capture@w3.org > December 2012

Re: How to check if permission denied?

From: Adam Bergkvist <adam.bergkvist@ericsson.com>
Date: Fri, 7 Dec 2012 07:44:13 +0100
Message-ID: <50C1903D.1010503@ericsson.com>
To: Harald Alvestrand <harald@alvestrand.no>
CC: Martin Thomson <martin.thomson@gmail.com>, "public-media-capture@w3.org" <public-media-capture@w3.org>
On 2012-12-06 22:52, Harald Alvestrand wrote:
> On 12/06/2012 10:40 PM, Martin Thomson wrote:
>> On 6 December 2012 12:15, Harald Alvestrand <harald@alvestrand.no> wrote:
>>> I'm afraid that application developers will be unable to avoid selecting
>>> devices that give a bad user experience.
>> A much clearer edit, thanks.
>>
>> How much does the proposed deviceId constraint affect this view?
>> Would your answer perhaps be "not a lot, even though it might be used
>> to prevent recurrence of the bad experience".
> Yes - that's a better formulation than I'm able to come up at this time
> of night!

The usability gain I see with mandatory constraints is to not have the 
user select a device that the app knows in advance won't meet the 
requirements. However, the "early return" (no selector UI) if no devices 
met the mandatory constraints is a fingerprinting issue. The "early 
return" is also problematic if we want to support selecting a file as 
your video input. Because even if you don't have an HD camera, you could 
have an HD file that you would like to use as your input.

Could we have a solution where the selector UI is always shown even 
though no "real" devices met the mandatory constraints? In that case you 
could still select a file to emulate, e.g., a camera.

Example UI where two "real" devices meet the mandatory constraints.
===================
[Available devices]
HD Cam 1
HD Cam 2
File input
-------------------
[Unavailable devices (grayed out)]
SD Cam 1
===================

Example UI where zero "real" devices meet the mandatory constraints.
===================
[Available devices]
File input
-------------------
[Unavailable devices (grayed out)]
SD Cam 1
SD Cam 2
===================

Some benefits are:
* Consistency - The user always sees all his/her devices, but can tell 
from the UI that they're not selectable for this session. This could 
also avoid the case where a user thinks that the browser can't find the 
camera, but real reason is that the camera doesn't meet the mandatory 
constraints.
* Less fingerprinting - The UI stops "under the hood" fingerprinting 
polling.
* Allows to user to select a file.

/Adam
Received on Friday, 7 December 2012 08:30:47 UTC

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