Re: Constraints structure and Capabilities API

On Feb 23, 2012, at 6:41 PM, Josh Soref wrote:

> Please don't cross post, it makes for a mess, pick a list, and then send the other list a reference to it:
> 
> http://lists.w3.org/Archives/Public/public-media-capture/2012Feb/0041.html
> fwiw, that comes from a header you'll receive in your message that looks like:
> Archived-At: <http://www.w3.org/mid/F6D7A22F-F7DF-4734-946B-08DD87993587@voxeo.com>

I am aware of the usual recommendation not to cross-post.  There have been substantial complaints about the discussions of this particular topic not being visible to all, so I thought I would do it in this instance.  From now on I will send new versions to the webrtc list and send a reference to the media capture list.   I will reply to your technical comments in another email.

-- dan

> 
> Dan wrote:
>> If the
>> browser is unable to satisfy all mandatory constraints, the media request call
>> MUST fail with an appropriate error message and list the mandatory constraints
>> it was unable to satisfy.
> 
> What happens if a browser can't meet some combination of constraints but could do them individually? :)
> 
>> An initial list of valid constraints is:
> 
> Seems reasonable.
> 
>> Example:
>> {0:{video-min-height:600, mandatory:true},
>>  1:{video-max-aspectratio:1.333333333333},
>>  2:{video-min-timebetweenrefframes:20},
>>  3:{video-max-bandwidth:500, mandatory:true},
>>  4:{video-min-framerate:30},
>>  5:(video-autowhitebalance:on}}
> 
> What happens if someone does:
> 
>  {0:{video-min-height:600, mandatory:true},
>   1:{video-max-height:500, mandatory:true}}
> 
> :)
> 
> 
>> A call to getCapabilities() returns a JavaScript Array containing, for each
>> device/media stream/channel, all relevant constraints (the constraints as
>> specified by the constraints API). For example,
>> 
>> {camera001:{
>>   video-min-width:  800,
>>   video-max-width:  1024,
>>   video-min-height:  600,
>>   video-max-height:  768,
>>   video-min-aspectratio:  1.333333333333,
>>   video-max-aspectratio:  1.333333333333,
>>   video-min-framerate:  24,
>>   video-max-framerate:  60,
>>   video-min-pixelrate:  15,
>>   video-max-pixelrate:  47,
>>   video-min-timebetweenkeyframes;  20,
>>   video-max-timebetweenkeyframes:  40,
>>   video-min-bandwidth:  1.5,
>>   video-max-bandwidth:  3.5},
>> camera002:{
>>   video-min-width:  1600,
>>   video-max-width:  1920,
>>   video-min-height:  1080,
>>   video-max-height:  1200,
>>   video-min-aspectratio:  1.33333333333,
>>   video-max-aspectratio:  1.77777777777,
>>   video-min-framerate:  24,
>>   video-max-framerate:  120,
>>   video-min-pixelrate:  57.6,
>>   video-max-pixelrate:  248,
>>   video-min-timebetweenkeyframes;  20,
>>   video-max-timebetweenkeyframes:  40,
>>   video-min-bandwidth:  8,
>>   video-max-bandwidth:  29.4},
>> audio001:{
>>   audio-min-bandwidth:  1.4,
>>   audio-max-bandwidth:  128,
>>   audio-min-mos:  2,
>>   audio-max-mos:  5,
>>   audio-min-codinglatency:  10,
>>   audio-max-codinglatency:  50,
>>   audio-min-samplingrate:  8000,
>>   audio-max-samplingrate:  48000}}
> 
> For trusted mode, this is ok, for untrusted mode, this is incredibly fingerprint.
> 
> I wouldn't mind something where the browser returns values based on what was requested...
> 
>> Note that bandwidth and latency capabilities reflect the combined effect of
>> that device and any codecs we have available to use with it.
> 
> 
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Received on Friday, 24 February 2012 13:18:50 UTC