[vorbis-dev] Idea for gapless tracks

[Ingo Saitz]

MoiN

On Fri, Jan 05, 2001 at 10:20:44AM -0600, Davy Durham wrote:
> Beni Cherniavsky wrote:
> > Instead of smoothing you can cross-mix, which is implemented in many
> > players anyway.  If you need sample-precision you can extrapolate both
> > signals a little with the spectrums they have at their begginings /
> > ends.  Maybe you can use the extra samples that the encoder puts in
> > and marks to be cropped - you can add a flag to encoder to force it
> > leaving so minimal extra samples on both ends - but I'm afraid that
> > this abuses the specification, since another encoder is permitted to put
> > any garbage he wants there.  So better put it in the player.
> > In any case I'm not sure whether it would sound better :-)
> 
> I was going to suggest this, but wouldn't this change the length (which for some reason
> may be undesirable to any degree)?

Another idea may be: include (maybe in another substream) small
portions of the beginning and end of the track in uncompressed
form. If the decoder is playing a single file he can safely
ignore the substream, but if the encoder is playing in gapless
mode he can crossfade between the decoded stream and the original
audio. This way you *don't* get gaps anymore onless the uncompressed
data does not match.

I don't think 2-4k of additional uncompressed data would hurt too
much, and you could even compress it with some lossless codec
(squish?).

    Ingo

-- 
"Disclosed Source" programs mean software for which the source code is
available without confidential or trade secret restrictions and for which 
the source code and object code are available for distribution without
license charges.

--- >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-dev-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.