[vorbis-dev] New entropy coder

Segher Boessenkool segher at kernel.crashing.org
Fri Oct 10 16:17:30 PDT 2003



Eduardo Enrique González Rodríguez wrote:
> Hello, I am a computer engineering student and compression hobbyst
> and have recently developed a new entropy coding algorithm. It  can be
> used to achieve compression proper of arithmetic coders at very high
> speeds -almost like Huffman codecs-.
> 
>         Since it could be of interest to you, I send it as an attachment -code
> and technical report-. Please, drop me a line in case you have any doubt or 
> suggestion.

Very interesting approach.  Yeah, I can see why this achieves
compression ratios very near arithmetic coding.  I also can see
why it is about the same speed as Huffman codes.  Very very
interesting.

I have some suggestions to make, but first I'll hack up rehuff
(my Vorbis stream recoding tool; it replaces the standard Huffman
codes which the libvorbis encoder uses (which are optimal
_statistically_ for the given encoding settings) with Huffman
codes which actually are optimally _for the given stream_) to
output some statistics on how well your algorithm will perform
(and also how well it will perform with an obvious modification,
that should prove to help a bit).

Now, I wonder whether anybody already thought of this (and
patented it).  It seems pretty darn obvious if you look at it ;-)

<p>Segher

p.s.  For those wondering, I soon will package up rehuff, and
put a user interface on it etc.  It will be GPL.  I just need
to find the time (and incentive) to do it.  Fanmail wouldn't
hurt... (doh)
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