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Re: a question about dimensions...

From: David Singer <singer@apple.com>
Date: Fri, 06 May 2011 09:33:52 -0700
Cc: Davy Van Deursen <davy.vandeursen@ugent.be>, Media Fragment <public-media-fragment@w3.org>
Message-id: <DB958946-C035-4194-9B01-A5A3246299A1@apple.com>
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>

On May 5, 2011, at 21:50 , Silvia Pfeiffer wrote:

> On Tue, Mar 22, 2011 at 6:25 PM, Davy Van Deursen
> <davy.vandeursen@ugent.be> wrote:
>> Hi David,
>> 
>> On 21/03/2011 15:55, David Singer wrote:
>>> 
>>> Guys
>>> 
>>> I am not sure that 'named' is really a dimension.
>>> 
>>> I understand focusing on time; focusing on a spatial area; and focusing on
>>> tracks.  These are indeed orthogonal axes.
>>> 
>>> But you use names to focus on a section, which seems to be a named
>>> time-subpart.
>>> 
>>> Specifically, can I use names for subsetting in any of the dimensions?  If
>>> I have a track called 'fred', are these equivalent?
>>> 
>>> http://www.example.com/thing#track=fred
>>> http://www.exampke.com/thing#id=fred
>>> 
>>> Would it not be cleaner to allow selection by name on any of the three
>>> axes (i.e. named timed periods, named spacial regions, named tracks)?
>> 
>> To me, 'named' can be seen as a kind of virtual dimension, which points to a
>> combination of any of the three "real" dimensions (i.e., time, spatial, or
>> track). The mapping between a named fragment and a combination of time,
>> spatial, or track is left to the application.
>> 
>> So for example: #id=fred_low could correspond to
>> #t=10,20&track=low&xywh=20,20,30,30. It is of course not required to combine
>> all dimensions: #t=30,40 could for example correspond to #id=blooper.
>> Similarly, #track=fred could correspond to #id=fred if this is defined
>> within the application; but as I said, the mapping is out of scope of the MF
>> spec.
> 
> I typically use #id to reference chapters, which are a subpart of the
> time dimension.
> 
> I'm currently dealing with a demo where I use WebVTT chapters to
> navigate a video. It would be really nice if the browser would just
> understand video.ogv#chapter2 and I wouldn't have to use script to set
> the currentTime to the chapters2 start and catch the ontimeupdate
> event to test if I've already gone beyond the end of the chapter2 to
> stop playback.
> 
> OTOH, this feature is not urgently needed compared to the temporal and
> track dimensions. If I could just convert the label to a time range
> through script and then do the media fragment addressing with #t, that
> would help a lot, too.
> 
> Silvia.

Bring back cue ranges!  It would be so easy if one could set up cue ranges that matched the chapters, and then use the enter/exit events to set the labels and so on!


David Singer
Multimedia and Software Standards, Apple Inc.
Received on Friday, 6 May 2011 16:34:29 GMT

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