
Patent on Burrows-Wheel Transform Range Encoding Compression Expired in 2017 - ohgreatwtf
Range Encoding, also known as arithmetic encoding, is the practical extension of arithmetic encoding https:&#x2F;&#x2F;www.drdobbs.com&#x2F;cpp&#x2F;data-compression-with-arithmetic-encodin&#x2F;240169251 to arbitrary data sets.
https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Range_encoding<p>The most well known range encoding algorithm is probably the one used in 7zip https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Lempel%E2%80%93Ziv%E2%80%93Markov_chain_algorithm<p>however burrows wheel transform based compression appears to improve over Lempel-Ziv.
https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Burrows%E2%80%93Wheeler_transform<p>Many of the best performers of the calgary challenge have been Burrows-Wheel transform based algorithms
http:&#x2F;&#x2F;mattmahoney.net&#x2F;dc&#x2F;dce.html<p>but it was patent encumbered until 2017.
http:&#x2F;&#x2F;www.compressconsult.com&#x2F;szip&#x2F; Michael Schindler&#x27;s szip with patent https:&#x2F;&#x2F;patents.google.com&#x2F;patent&#x2F;US6199064B1&#x2F;en
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powturbo
You might be interested on "Turbo Range Coder" [1] a bitwise and multisymbol
range coder, that can be used as a library.

A command line compressor is also included

1 - [https://github.com/powturbo/Turbo-Range-
Coder](https://github.com/powturbo/Turbo-Range-Coder)

