[vorbis-dev] BCB build successful?

David K. Gasaway dgasaway at bigvalley.net
Wed Jan 31 19:21:59 PST 2001

> heh its ok, I didn't understand rehuff untill someone explained it to
> me ..
> Huffman compression is essentially a substitution cypher where short
> bit patterns are substituted for byte patterns ... to do the
> substitutions you need a translation device called a "huffman tree" (a
> special case of a binary tree) ... but to make the whole thing work
> you have to have seen EVERY byte in the stream so you can count what
> patterns there are and how many of them there are, and a simple
> algorithim can build an optimal tree from that data.  

Oh, some of the discussion is coming back to me now...
Optimum Huffman codes given a certain source.

> So when all was said and done, you weren't using an optimal tree but a
> aproximation of one based on historical data.  Where rehuff comes in
> is it decompresess the data, generates an optimal tree for it, and
> recompressess it (lossless), and saves you a few extra percent space.

So, you think the codebooks are different, but the two output files 
are otherwise the same?  :-\

> IMHO rehuff should be a standard part of the encoding process :)
> So if the binaries you had have different codebooks, it would output
> different files which both should reduce (rehuff) down to a 3rd
> identical file ... though I suspect its different sources at this
> point?

Well, I don't follow that conclusion, but I don't know too much about 
audio coding (specifically).

> OD

David K. Gasaway
dgasaway at comports.com
Sound Blaster Pro - A professional way to blow your ears
Sig by Kookie Jar 5.98b http://go.to/generalfrenetics/
31 January 2001

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