[theora-dev] What sort of math i required?

[Mike Melanson]

On Thu, 11 Dec 2003, Martin Jeppesen wrote:

> Why are people still using Huffman? Haven't there come better algorithms
> since?

        Hey, if it works...but there are some alternatives. Most notably,
there is something called arithmetic coding which offers better
compression than Huffman. There is placeholder support for it in the JPEG
spec and probably other specs. The big problem with using it is that
someone has a patent on it and has not been shy about enforcing it. Oh,
and arithmetic coding is also really, really slow, on both sides (coding
and decoding).

        Off the top of my head, there is something called Rice coding.
This is still Huffman coding, but in a pattern that follows a certain
statistical model. I have read that it is used in Meridian Lossless
Packing (MLP) used to compress DVD audio, as well as in Free Lossless
Audio Compression (FLAC).

        There is also something called Golomb codes. They are used in
H.264 (from which SVQ3 and probably other methods are derived). I am not
sure if they are a type of Huffman codes or something different.

> Does there excist a wavelet codec today?

        Intel Indeo Video versions 4 and 5 are supposed to be based on
wavelet theory (as opposed to earlier versions which were VQ).


--
	-Mike Melanson

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