[vorbis] xml stream formats

[Michael Smith]

>You want to integrate the lyrics with time signitures with the stream? No
>problem:
>
><?xml version="1.0"?>
><!DOCTYPE vorbis-metadata SYSTEM "http://www.xiph.org/vorbis-lyrics.dtd">
><vorbis::metadata>
>  <timestamp t="00:01.38"/> 
>  <chord symbol="Am" fingering="http://www.xiph.org/guitarcharts/Am.png"/>
>  <lyric>Pic</lyric>
> </vorbis::metadata>
>
>Shove each of these little XML lyric/subtitle/whatever packets in where
>you need them. Notice how small they are? Think of how tiny they'll be
>once you compress them with zlib (we're going to do this, right?).
>

Well, this isn't really what you were getting at, exactly - but this makes
a whole lot more sense. Basically, each packet would be an entire xml
document. This gets around my primary objection to XML. MUCH nicer.

I'm still not convinced that XML is neccesarily a good idea for the
purposes that are being proposed, but doing it like this will make it clean
and workable. I'll stop objecting, but I DO still want people to come
forward with a REAL, complete argument as to why XML is a good idea. 

My main objection to XML now is about the complexity of XML - it's not THAT
bad, but an XML parser takes up a significant amount of space. For example,
the winamp plugin will almost certainly NOT ever support any metadata
format based on XML, because of this. We want to get the plugin into the
main winamp distribution, and they won't allow it in if it gets too big.
I'm guessing that adding an XML parser would double (at least) the size of
the compiled plugin. I don't WANT to reject XML because of this, but we
have to look at things realistically.

Note that zlib won't compress this sort of thing all that much. It's just
too short, so the (fairly small) headers get significant. Realistically,
we'll probably have sections a little longer, but not all that much. Easy
to get around that, by making metadata packets not independent, but that's
certainly a bad idea. However, is this worth worrying about? Metadata won't
ever take up THAT much space in the stream.

Michael

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.