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

Re: [Bug 25298] How to represent VideoFacingMode if browser is not able to detect the FacingMode of the camera.

From: Harald Alvestrand <harald@alvestrand.no>
Date: Mon, 28 Apr 2014 17:08:27 +0200
Message-ID: <535E6EEB.5040500@alvestrand.no>
To: public-media-capture@w3.org
On 04/24/2014 07:58 AM, bugzilla@jessica.w3.org wrote:
> https://www.w3.org/Bugs/Public/show_bug.cgi?id=25298
>
> --- Comment #18 from Kiran <kiran.guduru@samsung.com> ---
> (In reply to Jan-Ivar Bruaroey [:jib] from comment #14)
>> (In reply to Paul Neave from comment #2)
>>> Agree, but perhaps rather than "unknown" this case should simply be JS's
>>> undefined property?
>> "unknown" = not left, right, user or environment, but something else.
>> "undefined" = unconstrained.
>>
>> These are different. I think it would be quite fun actually to constrain on
>> "unknown". Give me all your new and wonderfully odd cameras!
>>
>> Also, since we don't have negative constraints, this lets us express things
>> like "not environment" using exclusion ['user', 'left', 'right', 'unknown'].
>>
>> Perhaps a better name would be "other"?
> I don't have any problem with name, whether it is "unknown" or "other". I
> concentrated much on the feature.
>
> The intention of proposing "unknown" is to cover the case where
>
> 1. Direction of facing is UNKNOWN in cases where we connect an external camera
> using USB / bluetooth (ofcourse user can change the direction in the middle of
> the session).
> 2. Rotating cameras apart from fixed top, down cameras.
>

This bug, with 18 comments in bugzilla so far, is clearly showing the 
reasons why I dislike Bugzilla as a discussion focus point.

WRT the "default" notation: I'm unhappy with the idea of depending on a 
proposed feature of WebIDL that last had activity on the bug in 2012. 
That doesn't seem like it's a recipe for getting things done here.

I think we need to separate the contexts in which VideoFacingMode is used:

- When reporting settings, one wants to report "something that is not 
any of the defined states". It is a good question if there needs to be a 
difference between "none of the above" and "I don't know" (in the latter 
case, the camera *might* be pointing at "user" or "environment" - but 
the browser doesn't know; in the former case, one would assume that the 
browser knows it doesn't.)

- When constraining camera choice, the constraint has to have some 
value. If "none of the above" is going to be a semantic we want to 
express, "none of the above" has to have some value.

My instinctive reaction is to go for the simplest solution:

- "none of the above" can't be expressed as a constraint. It's not 
important enough to complexify things.
- We allow only expression of the "I don't know" semantic of a state, 
and represent it by not returning this value in the output of getSettings().

Both of which need a sentence in the spec, but neither of which changes 
the WebIDL, I think.

What do people think?
Received on Monday, 28 April 2014 15:09:00 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 16:26:26 UTC