[ogg-dev] Feedback on XML metadata namespace

Ian Malone ibmalone at gmail.com
Sat Sep 8 02:40:05 PDT 2007

Daniel Aleksandersen wrote:
> Hi again list,
> Attached is a much improved version of yesterday's draft. Introducing the 
> audio:collection:artwork element to deal with album cover graphics and 
> such.
> After giving it much though; I decided to drop the audio:preformers and 
> audio:recording elements. They have been replaced by audio:entities which 
> is supposed to contain all involved organisations and persons. 
> audio:recording:rights, :date, and other elements related to the recording 
> have been changed to audio subsets.
> I got a question about the use of URNs for the URI attribute. URNs are a 
> subset of the URI specification. I know there is no way of resolving URNs 
> as of now. But I do mean they are a much better way to describe a physical 
> resource than using a URL. A URN says ‘what’, where a URL says ‘where’. The 
> x- suffix is present because the ISRC numbering is not a registered URN 
> name space. Note that any URI can be used. For example a web music store 
> may set the attribute to point to that particular song in their online 
> catalogue. Example URI attribute describing a CD by it's ISRC number in a 
> URN: urn:x-isrc:0123456789

With metadata resolving doesn't matter very much anyway,
what matters is uniquely identifying the resource.

> I have looked closer at the Dublin Core, and MPEG-7 metadata. This XML 
> format is very much more detailed than any of those formats. Compatibility 
> and mapping against these older metadata formats will prove very difficult 
> without loosing functionality of this format. (Which will make this format 
> worthless.) Thoughts on this, anyone?

Dublin Core was probably enough, except there wasn't
quite enough flexibility in the defined relation
types.  A list of valid role types or a way to make
them meaningful to software and still allow extension
is important.

> I will create a page for discussing this format in the Xiph wiki in a couple 
> of days. I had hoped to get some feedback and suggestions from the emailing 
> lists before doing so.

<video encoding="application/theora+ogg" />
et cetera, I think you want to avoid duplicating technical
metadata like this which is held in Ogg Skeleton.  Within
a stream anyway, maybe for separate description of media
files it might be worthwhile.

<artwork uri="#embedded-image" />
Being able to specify resources within an Ogg stream is
something that would be useful.


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