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Topic: Arithmetic coding

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	Arithmetic Coding (AC)
		The biggest drawbak of the arithmetic coding is it´s low speed since of several needed multiplications and divisions for each symbol.
		A fast variant of arithmetic coding, which uses less multiplications and divisions, is a range coder, which works byte oriented.
		A tutorial on arithmetic coding from 1992 by Paul Howard and Jeffrey Vitter with table lookups for higher speed.
	www.data-compression.info /Algorithms/AC/index.htm (1380 words)

	PlanetMath: arithmetic encoding
		Arithmetic coding is a technique for achieving near-optimal entropy encoding.
		Since arithmetic encoders are typically implemented on binary computers, the actual output of the encoder is generally the shortest sequence of bits representing the fractional part of a rational number in the final interval.
		This is version 1 of arithmetic encoding, born on 2002-03-08.
	www.planetmath.org /encyclopedia/ArithmeticCoding.html (239 words)

	Arithmetic Coding :: Source Coding (Communications Toolbox)
		Arithmetic coding offers a way to compress data and can be useful for data sources having a small alphabet.
		The length of an arithmetic code, instead of being fixed relative to the number of symbols being encoded, depends on the statistical frequency with which the source produces each symbol from its alphabet.
		Arithmetic coding requires statistical information about the source of the data being encoded.
	www.mathworks.com /access/helpdesk/help/toolbox/comm/ug/fp6596dup2.html (241 words)

	Arithmetic coding - Encyclopedia, History, Geography and Biography
		Arithmetic coding is a method for lossless data compression.
		Arithmetic coding and range encoding can be regarded as different interpretations of the same coding methods; arithmetic coders can be regarded as range encoders/decoders, and vice-versa.
		However, there is a tendency for arithmetic coders to be called range encoders when renormalization is performed a byte at a time, rather than one bit at a time (as is often the case with arithmetic coding), but this distinction is not definitive.
	www.arikah.com /encyclopedia/Arithmetic_coding (2030 words)

	NationMaster - Encyclopedia: Huffman coding
		The term refers to the use of a variable length code table for encoding a source symbol (such as a character in a file) where the variable-length code table has been derived in a particular way based on the estimated probability of occurrence for each possible value of the source symbol.
		A variable length code is a data compression code in which the length of the output of the code is dependent not only on the length of the input of the code, but also the content of the input.
		A prefix code, also known as a prefix-free code or comma-free code, is a code constructed so that any partial code word, beginning at the start of a full code word but terminating prior to the end of that code word, is not itself a valid code word.
	www.nationmaster.com /encyclopedia/Huffman-coding (910 words)

	Science Fair Projects - Arithmetic coding
		There is profound similarity between arithmetic coding and range encoding, so much so that their performances can usually be expected to be almost identical, with range encoding only being a few bits behind if there is indeed any difference.
		Range encoding, unlike arithmetic coding, is generally believed to not be covered by any company's patents.
		Some commenters feel that the notion that no kind of practical and effective arithmetic coding can be performed without infringing on valid patents held by IBM or others is just a persistent urban legend in the data compression community.
	www.all-science-fair-projects.com /science_fair_projects_encyclopedia/Arithmetic_encoding (1828 words)

	PlanetMath: arithmetic encoding
		Arithmetic coding is a technique for achieving near-optimal entropy encoding.
		Since arithmetic encoders are typically implemented on binary computers, the actual output of the encoder is generally the shortest sequence of bits representing the fractional part of a rational number in the final interval.
		This is version 1 of arithmetic encoding, born on 2002-03-08.
	planetmath.org /encyclopedia/ArithmeticEncoding.html (239 words)

	QccENTArithmeticEncodeStart.3
		Arithmetic coding can be either adaptive, in which the frequency-count information in the arithmetic model is updated after each symbol is encoded, or nonadaptive, in which the frequency counts stay static.
		In this example, the symbols are coded in two blocks; the first block is encoded with the first context, and the second block is encoded with the second context.
		Multiple-context adaptive arithmetic coding in which the previous symbol is used as the context of the current symbol.
	qccpack.sourceforge.net /Documentation/QccENTArithmeticEncodeStart.3.html (1452 words)

	Arithmetic Coding
		Arithmetic coding is a general technique for coding the outcome of a stochastic process based on an adaptive model.
		Although arithmetic coding works with any sample space, taking the outcomes to be bytes allows the coding of text in arbitrary character sets as well as binary files.
		The arithmetic coder is distributed with several illustrative models, culminating in PPMC, prediction by partial matching with model C. When introduced in the 1980s, PPM provided the best known compression on general text and binary data such as images.
	www.colloquial.com /ArithmeticCoding/javadoc/tutorial.html (1274 words)

	Kids.Net.Au - Encyclopedia > Arithmetic coding
		Arithmetic coding in data compression is the process of encoding a stream of data into a large binary fraction.
		Arithmetic coding actually refers to half of an Arithmetic Coding data compression system.
		An arithmetic encoder takes a string of symbols as input and produces a rational number in the interval [0, 1) as output.
	www.kids.net.au /encyclopedia-wiki/ar/Arithmetic_coding (408 words)

	Untitled Document
		Arithmetic coding is a statistical method for coding values that depends on the probabilities of these values.
		With arithmetic coding, an entire word or message is coded as one single number in the range of 0 to 1 (not inclusive the 1).
		The binary arithmetic coding engine is implemented as a state machine, where probability estimation is performed by a transition process between 64 probability states for the Least Probable Symbol (LPS).
	www.bilsen.com /aic/CABAC.htm (1718 words)

	CFXweb: Hugi 21 Online
		A model provides us with a probability distribution, whereas in arithmetic coding we are concerned only with writing bits to a file which represent it in the number of bits denoted by its self information.
		Arithmetic coding is the most important coding algorithm.
		To perform arithmetic coding, we assign each symbol a subinterval of [0, 1) which is proportional to (as close as we can get it) its probability.
	www.cfxweb.net /articles/hugi21/coarith.shtml (1560 words)

	Arithmetic Coding Tutorial
		If needed, a more basic implementation of arithmetic coding is described in references #2 and #4 (see reference section at bottom of page).
		For each iteration of the coding process, you continue to sub-divide the breakdowns for each additional character, by dividing the amount of the original breakdown area by the number of symbols plus the number of iterations minus 1.
		For a further example, below is a table illustrating the arithmetic coding for all possible strings of the given alphabet A, B, and C (see exercises 13 and 14 in Korfhage, Chapter 2).
	www.sis.pitt.edu /~jfondy/IS_2140/Arithmetic.htm (953 words)

	Effective Arithmetic Coding - Sachin Garg
		Code by Witten, Neal, and Cleary, which was published in CACM [1987] has become the de facto standard.
		The code here is based on Code published by Mark Nelson in February 1991 issue of Dr. Dobb's Journal, with his article Arithmetic Coding + Statistical Modeling = Data Compression.
		In this code, arithmetic coding is implemented using w = 64 and f = 30.
	www.geocities.com /schngrg/sgarith.html (403 words)

	Arithmetic Code Discussion and Implementation
		Arithmetic coding is similar to Huffman coding; they both achieve their compression by reducing the average number of bits required to represent a symbol.
		The standard form of arithmetic coding's encoding is based on fractional ranges on a probability line between 0 and 1.
		The standard form of arithmetic coding's decoding is also based on fractional ranges on a probability line between 0 and 1.
	michael.dipperstein.com /arithmetic/index.html (3334 words)

	Untitled
		The Huffman code table was guaranteed to produce the lowest possible output bit count possible for the input stream of symbols, when using fixed length codes.
		Huffman coding assigns an output code to each symbol, with the output codes being as short as 1 bit, or considerably longer than the input symbols, strictly depending on their probabilities.
		The code for the encoder as well as the decoder were first published in an article entitled "Arithmetic Coding for Data Compression" in the February 1987 issue of "Communications of the ACM", by Ian H. Witten, Radford Neal, and John Cleary, and is being published here with the author's permission.
	www.dogma.net /markn/articles/arith/part1.htm (5152 words)

	Compression: abstracts
		Arithmetic coding is the only entropy coder which achieves the entropy, that's why it's widely used, it's only back draw is speed, though.
		Quasi Static Model, is a model used for arithmetic coding or with the range coder, it's an approach between an static model and an adaptative one, and it results in a combination of both, which is useful.
		This article talks about a version of arithmetic coding which is almost twice faster, but loses a little bit of compression, however it's too litle (0.01%) that you don't notice it.
	www.arturocampos.com /abstracts.html (651 words)

	Arithmetic coding data compression/de-compression by selectively employed, diverse arithmetic coding encoders and ...
		A data compression/de-compression system includes a first arithmetic coding encoder, characterized by a first set of encoding conventions, which encoder generates a code stream that points to an interval along a number line in response to decision event inputs.
		The code stream can be adjusted to point to the same interval as code streams generated by one or more other arithmetic coding encoders characterized by encoding conventions differing in some way from those in the first set.
		Data compression apparatus using arithmetic coding wherein a data stream is input and decision events are generated in response to an encoding convention producing a code stream with values identifiable in terms of code points along a probability line, comprising:
	www.delphion.com /details?pn=US04891643__ (1129 words)

	Data Compression
		3.3 Universal Codes and Representations of the Integers
		Arithmetic coding (Section 3.4) has been reported to reduce a file to anywhere from 12.1 to 73.5% of its original size [Witten et al.
		While coding for purposes of data security (cryptography) and codes which guarantee a certain level of data integrity (error detection/correction) are topics worthy of attention, these do not fall under the umbrella of data compression.
	www.ics.uci.edu /~dan/pubs/DataCompression.html (1050 words)

	Arithmetic Channel Coding (Site not responding. Last check: )
		Arithmetic coding is a source coding algorithm which encodes the output of any discrete stationary source into a sequence of independent and uniformly distributed random variables.
		The code is specified by the probabilities and cumulative probabilities of the source.
		The decoder used in arithmetic source coding is based on the noiseless assumption and it cannot be used to decode the output of a noisy channel.
	userver.ftw.at /~claudio/acc.html (246 words)

	Parallelized binary arithmetic coding patent invention
		One parallelized binary arithmetic coding system uses linear approximation and simplifies the hardware by assuming that the probability of encoding or decoding a less probable symbol is almost the same while performing the encoding and decoding.
		The encoder applies a parallel binary arithmetic coding scheme to encode all of the data symbols of the set of binary data symbols in parallel and the set of data symbols includes more probable binary symbols and less probable binary symbols.
		The decoder applies a parallel binary arithmetic coding scheme to decode all of the data symbols of the set of binary data symbols in parallel and the set of data symbols includes more probable binary symbols and less probable binary symbols.
	www.freshpatents.com /Parallelized-binary-arithmetic-coding-dt20060907ptan20060197689.php (1114 words)

	Brown CS: Tech Report CS-92-17
		Arithmetic coding, in conjunction with a suitable probabilistic model, can provide nearly optimal data compression.
		In this article we analyze the effect that the model and the particular implementation of arithmetic coding have on the code length obtained.
		Periodlic scaling is often used in arithmetic coding implementations to reduce time and storage requirements; it also introduces a recency effect which can further affect compression.
	www.cs.brown.edu /publications/techreports/reports/CS-92-17.html (165 words)

	Arithmetic Coding
		In arithmetic coding, a message is encoded as a real number in an interval from one to zero.
		Arithmetic coding typically has a better compression ratio than Huffman coding, as it produces a single symbol rather than several seperate codewords.
		There also exists many patents upon arithmetic coding, so the use of some of the algorithms also call upon royalty fees.
	www.zipworld.com.au /~isanta/uni/arithmetic.htm (331 words)

	Contents
		In fact, for coding theory and cryptography, many systems use such large parameters that working practical ``by hand'' is virtually impossible and computers are not just useful but required.
		Cyclic codes are a very broad class of codes which includes, for example Reed-Solomon codes, the codes used on todays CDs.
		Other codes, such as the Goppa codes and the low density parity check codes, do not need group theory but were too advanced to fit naturally into chapter 3.
	web.usna.navy.mil /~wdj/book/node1.html (878 words)

	Effective Entropy Coding (Range Coding and Arithmetic Coding) - Sachin Garg
		For entropy coding, once the character probabilities are known, the individual symbols need to be assigned a range along a "probability line".
		For arithmetic coding, I have used Mark Nelson's code which was published with his 1991 DDJ article.
		Range coding was introduced by Martin in his 1979 paper.
	sachingarg.com /compression/entropy_coding/64bit (1525 words)

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