W3C home > Mailing lists > Public > public-media-annotation@w3.org > December 2009

Re: Asking for feedback on API design from the Web Browser Community

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Wed, 2 Dec 2009 09:16:46 +1100
Message-ID: <2c0e02830912011416x59bfcce2u190356e6044b3894@mail.gmail.com>
To: RaphaŽl Troncy <Raphael.Troncy@cwi.nl>
Cc: Joakim SŲderberg <joakim.soderberg@ericsson.com>, Doug Schepers <schepers@w3.org>, public-media-annotation@w3.org
For Ogg, all metadata is stored in VorbisComment headers and they are
track-specific, not file-specific. There can be file-wide metadata in
the skeleton track, but it's not used widely. Having it track-specific
also helps in keeping it around when segmenting the video into tracks
and recombining with others (e.g. to replace a audio track with a
different language).

ID3 headers are also associated typically with MP3 tracks, I think.

If I understand quicktime/mpeg-4 correctly, user metadata can be both
associated with the complete file (movie) and with tracks - e.g.
http://developer.apple.com/mac/library/qa/qa2001/qa1135.html .

I am mostly worried about getting a common metadata interface for
binary media files to use in HTML5 video and audio elements, so Ogg
and H.264 are my largest concern.


On Wed, Dec 2, 2009 at 8:49 AM, RaphaŽl Troncy <Raphael.Troncy@cwi.nl> wrote:
>> Most of the time the metadata is associated with tracks, so I wonder
>> how to address them.
> Is this really true? I agree it would be nice, but is there any metadata
> format widely used that offers such a granularity ? From my experience,
> metadata are generally global to a media file and therefore apply to all
> tracks. Complex metadata formats such as MPEG-7 allow to decompose a media
> into pieces (e.g. tracks) in order to attach metadata to these pieces, but
> people tend to say it is too complex.
>> For example: if I want the author of the video track and the composer
>> of the audio track?
> One more use case for the UC & Requirement document ?
> Cheers.
> †RaphaŽl
> --
> RaphaŽl Troncy
> EURECOM, Multimedia Communications Department
> 2229, route des CrÍtes, 06560 Sophia Antipolis, France.
> e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
> Tel: +33 (0)4 - 9300 8242
> Fax: +33 (0)4 - 9000 8200
> Web: http://www.eurecom.fr/~troncy/
Received on Tuesday, 1 December 2009 22:17:46 UTC

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