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Re: ISSUE-1: Combining Media Fragment URI with other time-clipping methods

From: Jack Jansen <Jack.Jansen@cwi.nl>
Date: Tue, 27 Jan 2009 23:54:59 +0100
Cc: RaphaŽl Troncy <Raphael.Troncy@cwi.nl>, Media Fragment <public-media-fragment@w3.org>
Message-Id: <6F55EC4D-AD84-45D6-90BB-8EF9F8D5875B@cwi.nl>
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>

On  27-Jan-2009, at 13:33 , Silvia Pfeiffer wrote:

>> I understand that specifying a time-clipping method, for example in  
>> SMIL, is
>> relative to the (timeline of the) resource. Therefore, what's  
>> happened if I
>> have:
>> <video clipBegin="5s" clipEnd="15s"
>> src="http://www.example.com/video.mov#t=20,30"/> ?
>>
>> Scenario 1: the media fragment is completely ignored, the UA plays  
>> the video
>> segment between the seconds 5 and 15
>>
>> Scenario 2: the clipping method is done relatively to the media  
>> fragment,
>> the UA plays the video segment between the seconds 25 (=20+5) and 35
>> (=20+15)
>>
>> Scenario 3: the clipping method is done relatively to the media  
>> fragment but
>> bound to the media fragment, the UA plays the video segment between  
>> the
>> seconds 25 (=max[20,20+5]) and 30 (=min[30,20+15]).
>>
>> In summary, how do we cover the cases where the media fragment is i)
>> encompassing, ii) embedding, iii) disjoint and iv) partially  
>> overlapping the
>> boundaries of the other time-clipping method?
>>
>> [1] http://www.w3.org/2008/WebVideo/Fragments/tracker/actions/13
>> [2]
>> http://lists.w3.org/Archives/Public/public-media-fragment/2008Nov/0095.html
>>
>
>>
> From my viewpoint, the URL points to a resource. Thus scenario 3 is
> the correct one, because from a SMIL POV, the clipBegin and clipEnd
> attributes are calculated on the resource.

I was going to say the same, but then I noticed one line in Raphael's  
original post:

>> I assume that the media fragment is regarded as in-context, that is,
>> http://www.example.com/video.mov#t=20,30 will play the fragment  
>> between the
>> seconds 20 and 30 of this resource, but the user sees the whole  
>> timeline of
>> the video and can click elsewhere on the slider, thus making a new  
>> request.
>

In this case I think my answer is: we don't know, and we don't care.  
If the video fragment is used in-context it depends on the application  
what the best solution is.
The only case we have some control over (and, also, the only case  
where I think it really matters) is if the fragment is used out-of- 
context.

For the out-of-context case I think we definitely want scenario 3.
--
Jack Jansen, <Jack.Jansen@cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma  
Goldman
Received on Tuesday, 27 January 2009 22:55:42 GMT

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