[vorbis] Bit Rate Peeling Quality

[Segher Boessenkool]

Daniel Schregenberger wrote:
> This was the initial question of this thread. The answer was like "we don't
> know exactly, but we suppose it to be a little less qualitative than a directly
> encoded file". The tools that exist (somewhere) by now produce bad peeled
> files, mostly cause the vorbis files need some restructurization to be easily
> peelable, but this is no problem, since this restructurization can be done
> lossless and very very fast.

This *is* a problem.  Indeed, losslessly recoding a Vorbis
stream can be very fast (depending on what exactly you want
to do), but a) it has to be done on *files*, not *streams*
(i.e. you need seeking), for some kinds of recoding at least,
and b) it is fast, but not *near* as fast as peeling, say,
1000x as slow.  This is a problem for streaming servers;
they can peel on the fly, but not recode on the fly.

For reducing bitrate for some other purposes (i.e., move
a file to a storage-tight portable player) there's no
problem with this approach, of course.

Cheers,

<p>Segher

<p>--- >8 ----
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