Re: Constraints 2014 new slides

On 3/27/14 1:49 PM, Dominique Hazael-Massieux wrote:
> Is there any browser that actually supports the current constraint
> syntax? My understanding was there isn't, and as a result, there must be
> very few (if any) real applications that rely on the current syntax
> (beyond {video: true, audio: true} which I understand the new proposal
> would support).

Exactly, there are zero implementations of spec-constraints in the field.

Allow me prove it. There is one constraint implementation, but look at 
what it supports:

>From 
https://webrtc.googlecode.com/svn/trunk/samples/js/demos/html/constraints-and-stats.html 
:
> {
>   "audio": true,
>   "video": {
>    "mandatory": {
>     "minWidth": "300",
>     "maxWidth": "640",
>     "minHeight": "200",
>     "maxHeight": "480",
>     "minFrameRate": "30"
>    },
>    "optional": []
>   }
> }

This is not to spec, and moreover, spec does not work, not even in 
Canary. Try this 
https://bug947665.bugzilla.mozilla.org/attachment.cgi?id=8397955 and 
you'll get:

Camera constraints are 
{"audio":true,"video":{"mandatory":{"width":{"min":300,"max":640},"height":{"min":200,"max":480}},"optional":[]}} 
attachment.cgi?id=8397955:220 
<https://bug947665.bugzilla.mozilla.org/attachment.cgi?id=8397955>
2Not connected yet attachment.cgi?id=8397955:220 
<https://bug947665.bugzilla.mozilla.org/attachment.cgi?id=8397955>
GetUserMedia failed


So it is not true that the current spec is rooted in current use.

People will need to change constraints already, likely as soon as 
Firefox implements the spec.

It is not too late.


>> the major benefit of this is better WebIDL conformance
> I think the improve readibility and writability for developers is also a
> pretty important benefit.

+1. I think some devs at least will look to the spec for syntax. In any 
case, whether they do or not, I think they should be able to, and that 
it needs to be easy to read for everyone, for this to be successful.

>> WRT to the details:
>> As I mentioned in a previous message, this doesn't seem to be
>> generalizable to talk about multiple instances of audio and video.
> Is that something the current constraints proposal support?
>
>> I share Cullen's concern about not being able to list a set of
>> devices in order of preference. This is basic functionality.
> Doesn't "prefer" combined with sourceId give that?

Yes, it could be clearer in the proposal, but I suggest we infer a 
preferred order in sequences (possibly only when using "prefer"?) - E.g. 
this should do what you want:

   var constraints = {
     video: {
       prefer: ["sourceId"],
       sourceId: ["4930cde4-09ed-4397-81d2-8163ce322d36",
"4930cde4-09ed-4397-81d2-8163ce322d36"],
     }
   };

.: Jan-Ivar :.