Re: Questions about the MediaStream Image Capture API proposal

Giri

comment inline; maybe note about frame grabbing in document would be helpful as the question might come up again.

regards, Frederick

Frederick Hirsch
Nokia



On May 30, 2013, at 5:29 PM, ext Mandyam, Giridhar wrote:

> Hello Rob,
> Thanks for your feedback.  I will get out a revision of the spec soon.
> 
> Couple of things to note:
> 
> 1. Yes, the link on the spec to what would be the W3C Mercurial instance is broken.  Regarding Mercurial, I have only uploaded here so far:  https://dvcs.w3.org/hg/dap/raw-file/tip/media-stream-capture/ImageCapture.html.  As was said previously, when this progresses to FPWD then we could also have a version available at http://www.w3.org/TR/image-capture/.  Regardless, I'll correct this in the spec in the next version to avoid confusion.
> 
> 2.  I have eliminated all references to frameGrabber (there was one left in by error) on the Mercurial version.  As Adam pointed out, we have decided not to have this.  If you want such a feature, setInterval(track.getFrame(), time_interval) or setTimeout (track.getFrame(), time_lag) is your best bet.  If the capture device is not ready to return a fresh frame, then an ImageCapture error event can be fired with the code set to FRAME_GRAB_ERROR.  
> 

maybe a note to this effect in the draft would be helpful.

> I guess you could define an onloadeddata event handler, but near as I can tell there would have to be a corresponding DOM element for the media.  The intention of the ImageCapture spec was to avoid creation of DOM elements for the API (in contrast to the previous approach in Media Capture and Streams - see the photo example in http://www.w3.org/TR/2012/WD-mediacapture-streams-20120628/#examples).
> 
> 3.  Now that we have a new WD of the Media Capture and Streams spec, I also need to modify the constructor to take in a VideoStreamTrack.  I will be doing so in the next version of the spec, which I plan on sending out next week.
> 
> -----Original Message-----
> From: Rob Manson [mailto:roBman@mob-labs.com] 
> Sent: Thursday, May 30, 2013 1:48 AM
> To: public-media-capture@w3.org
> Subject: Re: Questions about the MediaStream Image Capture API proposal
> 
> OK thanks Adam.
> 
> So would .onloadeddata be a better way to repeat calls to getFrame() or is it really just via setTimeout/setInterval?
> 
> roBman
> 
> 
> On 30/05/13 18:06, Adam Bergkvist wrote:
>> On 2013-05-30 09:18, Rob Manson wrote:
>>> Thanks Stefan.
>>> 
>>> Hopefully this will include some looping mechanism for stream 
>>> processing like frameGrabber() sounded like it was intended to be 8)
>> 
>> On a working group call, we came to the conclusion that the frame 
>> grabber API (periodic grabs) didn't add anything you couldn't easily 
>> do with getFrame() and JavaScript timers (setTimeout/setInterval). 
>> That's why it's gone.
>> 
>> /Adam
>> 
>> 
>> 
> 
>

Received on Monday, 17 June 2013 14:25:46 UTC