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Simon G Best (talk | contribs) →Range encoding and arithmetic encoding: Added references to what seem to be Martin's original paper. |
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:I don't really like the change. It confuses to the patent issue, which, as far as I can tell, is the only reason anyone cares about range coding. The reason range coding is believed to be without patent issues is because (again, as far as I can tell) it's an older form of arithmetic coding. Thus it was prior knowledge by the time any patents could have been filed that wouldn't have expired by now. The claim that arithmetic coding is a form of range coding seems wrong to me, since range coding claims to be a specific method, a fixed procedure to relate input to output. In contrast, arithmetic coding is a family of methods and, although it initially related specific input to specific output, it now has variants which trade off compression ratio (output) for performance (speed), and which consider how the probability models should adapt. The problem with arithmetic coding then is that there are lots of variants, so, while some forms of arithmetic coding are under patent, others aren't. So relabeling a specific type of arithmetic coding as "range coding" has the benefit that people know, "This is the type of arithmetic coding that can be done without worrying about patents." Of course, this is no small feat, as patent issues have prevented the adoption of arithmetic coding in applications where, technologically speaking, it would have significantly helped. [[User:Calbaer|Calbaer]] 22:10, 21 July 2006 (UTC)
::What appear to be copies of Martin's original paper can be found at [http://www.compressconsult.com/rangecoder/] and [http://www.data-compression.info/Algorithms/RC/] (they're the same one, but one's gzipped). I'll come back to this once I've had a good read through.
::--[[User:Simon G Best|Simon G Best]] 23:57, 21 July 2006 (UTC)
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