[vorbis] had a thought on peeling last night

[Alex Iribarren]

Hi,
Well, I'm not authoritative on this subject, but from what I understand,
this wouldn't work because the result of encoding a sound file is not
linear. What this means is that a q10 file is not just a q9 file with
some extra data. Or to explain it a different way, a q9 file is not a
subset of a q10 file.

I thought of something similar a while back (check the June 2001
archives). My idea was that you could stream, for example, a q1 file and
in a different stream all the peeled-off information that would turn the
q1 stream into a q2 stream. I was told this was not possible because a
q2 file is not just a q1 file with extra bits.

Alex

On Sat, 2002-12-21 at 10:35, Martin Blackwell wrote:
> I was up late last night, and i had a thought on peeling that would probably provide 100% accurate peeling data to a decoder, but take a maximum of 1101 times normal time to encode (taking into account the range from q-1 to q10 ).
> 
> say you want to encode a track at q10, but you want it to be peelable.
> the 1101 encoder would encode from the source at every quantifiable level (since there are 2 decimal points of quality in at least oggdrop, giving 100 quantifiable levels per integer level of quality, giving 1001 from q0 to q10, and an extra 100 for q-1 to q-0.01).
> the 1101 encoder would then compare the resulting files (assuming that they are all from an identical source) and basically say "all those bits of data not in q9.99 to q-1 belong to q10" and keeping going through things like "all those bits of data not in q10 to q5.54 and q5.52 to q-1 belong to q5.53" all the way down to "all those bits of data not in q10 to q-0.99 belong to q-1".
> eventually i'm guessing you would end up with a vorbis file with all the quantifiable samples & bits of data marked for peeling, making the job theoretically much easier & muich more accurate even with peelable streaming.
> 
> I didn't think it much further than that, cos i'm not a programming genius like everyone else on here, i just think a lot.

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