[vorbis] Multiple tracks per file, or continuous audio support

[M Bell]

--- Michael Smith <msmith at labyrinth.net.au> wrote:

> Vorbis has the same problem, BUT has a technique to
> deal with it correctly.
> In the bitstream, there's sufficient information
> that the decoder knows
> (this has worked since beta1, and even earlier)
> which bits to discard from
> the start and end - the output is, as a result,
> exactly the same length (in
> samples) as the original input.

Is this the same thing though?  Just because it
truncates the file to a certain length, can you be
sure the waveform will match properly with the
beginning of the next track?  Wouldn't it be better if
there was a special way to tell the Ogg encoder what
the first couple of milliseconds of the next track
were, so the frames could be encoded more towards
meeting the signal later?  Maybe that's overkill.  I'm
not sure what influence the zero-padding has backwards
on the signal.

> Vorbis actually gives you BOTH of these - as I
> described above, the
> individual tracks work fine. Also, vorbis lets you
> have multiple streams in
> a single file, following each other - so you could
> have one file with a
> seperate stream for each track, which gives you
> everything you wanted
> (although player UI typically makes this hard to
> take full advantage of -
> write your own player if that's a problem :-)

Yeah, actually I wouldn't be above writing some
management tools that would split a multiple-track
"archive" (properly handling continuity and track
identity) into many little tracks.  I would seriously
recommend "encouraging" players to figure this out on
their own, though.  I can't believe this hasn't been a
bigger issue than it seems (I really haven't heard
much about this problem).  Even MiniDisc had this
right from day one.

I guess I'm skeptical of the first solution.  I *did*
encode two tracks that play continuously, and played
them back in Ogg-enabled Winamp.  There's a small pop.
 This could be the player, though, cheating with its
own zero frames.

Anyone know of a way to check this out?  Any players
that are especially Ogg-smart, in that they drop
silence/breaks/etc.?

Thanks again...

Mike

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