[vorbis] had a thought on peeling last night

[Shawn Riley]

Daniel wrote-
>Did you mean to take like the first half of the packet (with wathever
>frequencies in there)? If yes, that's probably how peeling works. 

That's precisely what I was saying. But for the next part of your reply, what I meant was for the server to do the peeling instead - pass the "base" streams through, then cause the peeler on the server to break bits off one of the end of the "reconstitution" streams to adjust for the bandwidth.

Is there currently any resource available that explains the internal format of Vorbis bitstreams? I ask this, so people like me don't have to use up the time of the developers by asking "what about this...?"-type questions when with a bit of insight it's obvious that something can or can't work. Because I'm someone who falls in the gap between the "sound processing enthusiast, come programming graduate working on code", & the "casual listener satisfied with the FAQ".

Daniel continued-
>(Don't know
>exactly) And now I also know what you mean: By having two streams, you could
>get any quality between the lower one and the higher one, by
>"client-side-peeling". I just don't see exactly what it's good for: you could
>take all of the second stream, cause you need to recieve/send it anyway, and
>who refuses better quality if its "for free" :)

<p><p>I wrote-
>> Is it possible to convert an existing vorbis stream into a peelable stream
>just by reorganising the bits?
>
Daniel responded with-
>Hmmm...as far as I got it: the streams (files) Vorbis 1.0 produces are already
>peelable. (There exist a few *inoffical* tools to do it; search the archives
>for links.) It's just that the result isn't that good. With a little work on
>it, the quality could be (much?) better for peeled streams/files.

Sure, if we encode 10 CDs' worth of audio to Vorbis 1.0, then wish to peel it to a lower bitrate, then it could be done right now, but for what I understand, a q6 stream peeled to the same bitrate as a q1 stream, will probably sound worse than a q1. So what I wanted to know was, is it possible to take a current stream & reorganise the bits to give a current peeler the best possible output? This would be useful for batch processing, in a radio station or by a DJ that has a 100-CD collection of Vorbis files encoded with ver1.0. They won't want to re-rip/re-encode/re-tag, & will want to use a simple peel function to make it easier on the server.

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