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Re: Uniform access to metadata: XRD use case.

From: Jonathan Rees <jar@creativecommons.org>
Date: Wed, 11 Mar 2009 21:22:23 -0400
Message-ID: <760bcb2a0903111822m64b50ec1u7b8f465093826dec@mail.gmail.com>
To: Larry Masinter <masinter@adobe.com>
Cc: Eran Hammer-Lahav <eran@hueniverse.com>, "connolly@w3.org" <connolly@w3.org>, "www-archive@w3.org" <www-archive@w3.org>
(I missed the beginning of this; why is this on www-archive instead of
www-talk as Eran requested, and what document or message are you

Larry, you are right, many file formats do have a place to put
metadata. If there is a draft circulating that says otherwise it
should be corrected.

The problem is that each format does it in a different way. So how to
get at it, and modify it, if you're not familiar with the details of
every particular format, which of course is impossible. You could use
a registry of metadata extractors - for each media type, a program
that extracts metadata in a way peculiar to that type. You would also
need programs for altering the metadata.

I don't know where you'd put such a registry or how it would be maintained.

But for me, besides the problem of maintaining such a registry and the
difficulties of managing all these different formats in different
positions in the representation, the killer is situations where
getting the information from the "representation" is impossible in
principle. Examples include text/plain, encrypted content, content
that's inaccessible due to access control restrictions, server policy,
or server architecture, and exotic media types not known at the time
an application is written or in the hypothetical registry.

I agree that metadata should go in the "representation" whenever
possible. But you seem to be wilfully missing the point of the
exercise. I just don't get the resistance to agreeing on a uniform
protocol, to augment in-representation metadata or to provide it in
situations where it really is impossible or impractical to get it from
the "representation".


On Wed, Mar 11, 2009 at 7:21 PM, Larry Masinter <masinter@adobe.com> wrote:
>> First, not all representations are capable of embedding such metadata (i.e.
>> video, audio, etc.).
> Your other points notwithstanding, a minor correction to your examples, since it is possible and quite common to embed metadata in video and audio:
> http://www.adobe.com/devnet/xmp/
> "Part 3, Storage in Files (PDF, 629k) , provides information about how serialized XMP metadata is packaged into XMP Packets and embedded in different file formats. It includes information about how XMP relates to and incorporates other metadata formats, and how to reconcile values that are represented in multiple metadata formats."
> Note also availability of free open source implementation:
> The XMP Toolkit allows you to integrate XMP functionality into your product or solution. It supports Macintosh, Windows, as well as UNIX and comes with samples, documentation, source code and project files. The XMP Toolkit is available under the BSD license. The specification is provided under the XMP Specification Public Patent License (PDF, 24k).
> Larry
> --
> http://larry.masinter.net
Received on Thursday, 12 March 2009 01:23:12 UTC

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