Finite State Entropy - A new breed of entropy coder

This was a nice article.<p>In the comments Jarek Duda discusses some of the more technical details of the implementation and of his ANS paper that enabled this writeup. One cool thing I noticed is this:<p><pre><code> Another advantage of ANS is that we can slightly perturb the initialization procedure using a pseudo-random number generator initialized with cryptographic key (e.g. and also the number of block): for example choosing between the lowest weight symbol and the second best one. This way we get simultaneously a decent encryption for free. </code></pre> Does anyone know what modern compression tools use for entropy coding? Do they all use huffman and would this help them increase speed? What about gzip for HTTP transactions?

There is a nice treatment on entropy coders in Managing Gigabytes (<a href="http://ww2.cs.mu.oz.au/mg/" rel="nofollow">http:&#x2F;&#x2F;ww2.cs.mu.oz.au&#x2F;mg&#x2F;</a>). I highly recommend the text as it gives good background on entropy encodings and it also takes a nice engineering approach to implementation.

Arithmetic coding, one of the early victims of software patents.

&quot;In a nutshell, this coder provides the same level of performance as Arithmetic coder, but only requires additions, masks, and shifts.&quot;<p>Didn&#x27;t IBM&#x27;s Q-Coder also make the same claims?<p>Here&#x27;s another one: <a href="http://www.gvu.gatech.edu/people/official/jarek/courses/7491/Arithmetic2.pdf" rel="nofollow">http:&#x2F;&#x2F;www.gvu.gatech.edu&#x2F;people&#x2F;official&#x2F;jarek&#x2F;courses&#x2F;7491...</a>

Well, this is interesting.<p>I toyed around with entropy encoding at one point based on a republished copy of an old Dr. Dobbs&#x27; Journal article I found, and I managed to cleanly reimplement the described algorithm in Python and reproduce the example mentioned in the article... but eventually I hit a problem I wasn&#x27;t smart enough to debug. I&#x27;m eager to see whether this new algorithm is more approachable.

Does anyone know the real history with arithmetic encoders?<p>A lot of places seem to credit Rissanen, but I remember from when this was actually my field, that Elias did most of the work in the early &#x27;60s (and actually went on a tangent that Shannon considered in the &#x27;50s), and Rissanen&#x27;s contribution was getting the finite word length arithmetic considerations properly done.<p>In fact, when I studied this at the university (early 90s), it was introduced as &quot;Elias (aka Arithemetic) coding&quot;.

How does it compare to the algorithm used in FLAC or mpeg4 lossless? Is there a reasonable way to benchmark the differences? <a href="https://en.wikipedia.org/wiki/Golomb_coding#Simple_algorithm" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Golomb_coding#Simple_algorithm</a>

So if I understand this correctly, how much it outperforms Huffman greatly depends on the data being compressed. Which makes me wonder: what kind of real-life datasets would benefit the most from this new approach?