[vorbis-dev] Re: Special metaformat for ogg-files with multiple tracks

[Kenneth Arnold]

On Sun, Jan 20, 2002 at 03:32:16PM +0100, Lars Weber wrote:
> But seriously, you're refering here to the streaming capabilities
> described in (it seems to me) doc/oggstream.html, right?  If so, how well
> do these map to "local uses" like a single cd encoded as an ogg-file with
> multiple tracks?  E.g.: How hard would it be to make a graphical player
> display the individual tracks as if they were separate files?  Would this
> require scanning the entire file for the beginning of the individual
> tracks first?

When vorbisfile first opens an Ogg Vorbis file, it scans for all
chained streams. A program using the Vorbisfile API can easily query
the data it collects about them.

> And do there already exist tools to easily create and/or "un-create" such
> multi-track files?

You can simply concatenate two Ogg files (e.g. cat file1.ogg file2.ogg > chain.ogg).
For "un-creating" them, I'm not sure. vcut should be able to do this,
but it's definately an optimized special case of what it was really
intended to do (cut files in the middle of a stream). To list -- would
a small addition to either ogginfo or vcut (my preference would be
vcut) or both to handle Ogg-as-an-archive applications be justified,
or should this be another separate tool?

> > Though it would be useful to be able to tell ogg123 to start at stream
> > number x, or play streams x through y, or time w of stream x to time y
> > of stream z, etc.
> >
> > If there's a consensus that it's worth it (and not just more code
> > bloat), I'll do it. Wow I actually might have the time to also (for
> > once)!
> 
> I at least think that such a feature would be useful.

I think I'll work on the tool addition I mentioned above first, for
the simple reason that it's much easier.

I'll take a moment to rattle off what my thoughts are for ogg123:

* if existing decoder interfaces don't support it, add pre-reading so
we can detect formats
* detect .m3u (.ogu? for ogg? any better suggestions?) and .pls format
playlists, and play
* add time/stream play
probably some other stuff that's not on my mind right now.


-- 
Kenneth Arnold <ken at arnoldnet.net>
- "Know thyself."


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