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Re: ISSUE-2: What is the mime type of a media fragment? What is its relation with its parent resource?

From: Yves Raimond <yves.raimond@gmail.com>
Date: Tue, 27 Jan 2009 15:19:20 +0000
Message-ID: <82593ac00901270719u6e1892e5n204f785471ccd61d@mail.gmail.com>
To: Michael Hausenblas <michael.hausenblas@deri.org>
Cc: David Singer <singer@apple.com>, Media Fragment <public-media-fragment@w3.org>, RaphaŽl Troncy <Raphael.Troncy@cwi.nl>


> Good point re FRBR. I'd also target FRBR manifestations but I fear we will
> need end up with FRBR items.

The more I think about it, the more I'd think it would make sense to
see media fragments as FRBR manifestations. After all, other fragment
URIs (RDF and HTML) already work like that. They identify an object
within the target document, and not a part of the target document!


> Cheers,
>      Michael
> --
> Dr. Michael Hausenblas
> DERI - Digital Enterprise Research Institute
> National University of Ireland, Lower Dangan,
> Galway, Ireland, Europe
> Tel. +353 91 495730
> http://sw-app.org/about.html
>> From: Yves Raimond <yves.raimond@gmail.com>
>> Date: Tue, 27 Jan 2009 15:10:54 +0000
>> To: David Singer <singer@apple.com>
>> Cc: Michael Hausenblas <michael.hausenblas@deri.org>, Media Fragment
>> <public-media-fragment@w3.org>, RaphaŽl Troncy <Raphael.Troncy@cwi.nl>
>> Subject: Re: ISSUE-2: What is the mime type of a media fragment? What is its
>> relation with its parent resource?
>> On Tue, Jan 27, 2009 at 2:48 PM, David Singer <singer@apple.com> wrote:
>>> At 14:36  +0000 27/01/09, Michael Hausenblas wrote:
>>>> Dave,
>>>>>  a) the MIME type of the requested fragment is the
>>>>>  same as that of the original resource;  yes, that
>>>>>  might result in one-frame movies, and so on;
>>>> Sounds good. Didn't think about this one yet. But how do we technically do
>>>> this? I fear I don't understand. Could you be more precisely on this
>>>> option,
>>>> please?
>>> Well, I am trying hard to think of a case *in multimedia* where the
>>> statement
>>> "the type of a piece of X *cannot* be the same as the type of X"
>>> would be true.
>>> The obvious problem area is if you select a time-point in a video track of a
>>> movie, then a fragment cast as a movie would have zero duration -- it's more
>>> sensibly a picture.  Unfortunately, zero duration frames are explicitly
>>> forbidden in MP4, 3GP etc. (since they can make the visual display at a
>>> given time ambiguous).
>>> But this gets semantically tricky if there is sound;  what is the correct
>>> representation of a point in time of a sound track?  It's not right to drop
>>> it from the fragment (oof, we'd need media-type rules for what types get
>>> dropped and what don't).
>>> This is steering me towards wondering if a piece of X, in time, necessarily
>>> has some extension in time, i.e. a time-point is not a fragment (can you see
>>> a zero-width character if you meet one in the street?).
>> I think that raises lots of really interesting questions, and
>> highlight the need for a debate about what a media fragment actually
>> is. Is it a bunch of byte (in that case, it makes sense to associate a
>> mime-type with it), or is it an identifier for a piece of the content?
>> In other words, does it identify a FRBR item, or a FRBR manifestation?
>> I would personally go for the latter, which would allow us to use
>> media fragments for identifying a particular signal sample, a frame in
>> a video, etc.
>> Best,
>> y
>> --
>> Yves Raimond
>> BBC Audio & Music interactive
>> http://moustaki.org/
Received on Tuesday, 27 January 2009 15:20:04 UTC

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