Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony.
In mathematics and computer science, an algorithm is an unambiguous specification of how to solve a class of problems.
The Amiga is a family of personal computers introduced by Commodore in 1985.
Apple Lossless, also known as Apple Lossless Audio Codec (ALAC), or Apple Lossless Encoder (ALE), is an audio coding format, and its reference audio codec implementation, developed by Apple Inc. for lossless data compression of digital music.
Arithmetic coding is a form of entropy encoding used in lossless data compression.
MPEG-4 Audio Lossless Coding, also known as MPEG-4 ALS, is an extension to the MPEG-4 Part 3 audio standard to allow lossless audio compression.
In statistics and signal processing, an autoregressive (AR) model is a representation of a type of random process; as such, it is used to describe certain time-varying processes in nature, economics, etc.
In computing, a benchmark is the act of running a computer program, a set of programs, or other operations, in order to assess the relative performance of an object, normally by running a number of standard tests and trials against it.
Better Portable Graphics (BPG) is a file format for coding digital images, which was created by programmer Fabrice Bellard in 2014.
The Burrows–Wheeler transform (BWT, also called block-sorting compression) rearranges a character string into runs of similar characters.
bzip2 is a free and open-source file compression program that uses the Burrows–Wheeler algorithm.
The Calgary corpus is a collection of text and binary data files, commonly used for comparing data compression algorithms.
In mathematics, the term combinatorial proof is often used to mean either of two types of mathematical proof.
The following tables compare general and technical information for a number of file archivers.
compress is a Unix shell compression program based on the LZW compression algorithm.
Context mixing is a type of data compression algorithm in which the next-symbol predictions of two or more statistical models are combined to yield a prediction that is often more accurate than any of the individual predictions.
Cryptanalysis (from the Greek kryptós, "hidden", and analýein, "to loosen" or "to untie") is the study of analyzing information systems in order to study the hidden aspects of the systems.
In cryptography, a cryptosystem is a suite of cryptographic algorithms needed to implement a particular security service, most commonly for achieving confidentiality (encryption).
In signal processing, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation.
Data compression ratio, also known as compression power, is a computer science term used to quantify the reduction in data-representation size produced by a data compression algorithm.
David Albert Huffman (August 9, 1925 – October 7, 1999) was a pioneer in computer science, known for his Huffman coding.
In computing, Deflate is a lossless data compression algorithm and associated file format that uses a combination of the LZ77 algorithm and Huffman coding.
Delta (uppercase Δ, lowercase δ or 𝛿; δέλτα délta) is the fourth letter of the Greek alphabet.
Delta encoding is a way of storing or transmitting data in the form of differences (deltas) between sequential data rather than complete files; more generally this is known as data differencing.
The demoscene is an international computer art subculture focused on producing demos: self-contained, sometimes extremely small, computer programs that produce audio-visual presentations.
In numerical analysis and functional analysis, a discrete wavelet transform (DWT) is any wavelet transform for which the wavelets are discretely sampled.
Dolby TrueHD is a lossless multi-channel audio codec developed by Dolby Laboratories which is used in home-entertainment equipment such as Blu-ray Disc players and A/V receivers.
DTS-HD Master Audio (DTS-HD MA) is a combined lossless/lossy audio codec created by DTS (formerly Digital Theater Systems), commonly used for surround-sound movie soundtracks on Blu-ray Disc.
Information entropy is the average rate at which information is produced by a stochastic source of data.
Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike Prokaryotes (Bacteria and other Archaea).
Frequently asked questions (FAQ) or Questions and Answers (Q&A), are listed questions and answers, all supposed to be commonly asked in some context, and pertaining to a particular topic.
FLAC (Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation.
Free Lossless Image Format (FLIF) is a lossless image format (current version FLIF16 specification) claiming to outperform PNG, lossless WebP, lossless BPG and lossless JPEG 2000 in terms of compression ratio on a variety of inputs.
FreeArc is a free and open source file archiver developed by Bulat Ziganshin.
In mathematics, a function was originally the idealization of how a varying quantity depends on another quantity.
In computer science and operations research, a genetic algorithm (GA) is a metaheuristic inspired by the process of natural selection that belongs to the larger class of evolutionary algorithms (EA).
The Graphics Interchange Format, better known by its acronym GIF, is a bitmap image format that was developed by a team at the bulletin board service (BBS) provider CompuServe led by American computer scientist Steve Wilhite on June 15, 1987.
GNU is an operating system and an extensive collection of computer software.
Grammar induction (or grammatical inference) is the process in machine learning of learning a formal grammar (usually as a collection of re-write rules or productions or alternatively as a finite state machine or automaton of some kind) from a set of observations, thus constructing a model which accounts for the characteristics of the observed objects.
gzip is a file format and a software application used for file compression and decompression.
A heuristic technique (εὑρίσκω, "find" or "discover"), often called simply a heuristic, is any approach to problem solving, learning, or discovery that employs a practical method, not guaranteed to be optimal, perfect, logical, or rational, but instead sufficient for reaching an immediate goal.
In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression.
The Hutter Prize is a cash prize funded by Marcus Hutter which rewards data compression improvements on a specific 100 MB English text file.
Interleaved Bitmap (ILBM) is an image file format conforming to the Interchange File Format (IFF) standard.
In computing, indexed color is a technique to manage digital images' colors in a limited fashion, in order to save computer memory and file storage, while speeding up display refresh and file transfers.
Information theory studies the quantification, storage, and communication of information.
In mathematics, an injective function or injection or one-to-one function is a function that preserves distinctness: it never maps distinct elements of its domain to the same element of its codomain.
Interchange File Format (IFF), is a generic container file format originally introduced by the Electronic Arts company in 1985 (in cooperation with Commodore/Amiga) in order to facilitate transfer of data between software produced by different companies.
The International HapMap Project was an organization that aimed to develop a haplotype map (HapMap) of the human genome, to describe the common patterns of human genetic variation.
Intuition is the ability to acquire knowledge without proof, evidence, or conscious reasoning, or without understanding how the knowledge was acquired.
JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group.
JPEG 2000 (JP2) is an image compression standard and coding system.
JPEG XR (JPEG extended range) is a still-image compression standard and file format for continuous tone photographic images, based on technology originally developed and patented by Microsoft under the name HD Photo (formerly Windows Media Photo).
The kilobyte is a multiple of the unit byte for digital information.
In algorithmic information theory (a subfield of computer science and mathematics), the Kolmogorov complexity of an object, such as a piece of text, is the length of the shortest computer program (in a predetermined programming language) that produces the object as output.
The Lempel–Ziv–Markov chain algorithm (LZMA) is an algorithm used to perform lossless data compression.
Lempel–Ziv–Oberhumer (LZO) is a lossless data compression algorithm that is focused on decompression speed.
Lempel–Ziv–Storer–Szymanski (LZSS) is a lossless data compression algorithm, a derivative of LZ77, that was created in 1982 by James Storer and Thomas Szymanski.
Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch.
The following is a list of compression formats and related codecs.
Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data.
Lossless Transform Audio Compression (LTAC) is a compression algorithm developed by Tilman Liebchen, Marcus Purat and Peter Noll at Institute for Telecommunications, Technical University Berlin (TU Berlin), to compress PCM audio in a lossless manner, unlike conventional lossy audio compression algorithms (like MP3).
In information technology, lossy compression or irreversible compression is the class of data encoding methods that uses inexact approximations and partial data discarding to represent the content.
LZ77 and LZ78 are the two lossless data compression algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978.
Meridian Lossless Packing, also known as Packed PCM (PPCM), is a lossless compression technique for compressing PCM audio data developed by Meridian Audio, Ltd..
Monkey's Audio is an algorithm and file format for lossless audio data compression.
MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is an audio coding format for digital audio.
MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per ISO/IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the MPEG-4 Part 3 (MPEG-4 Audio) standard to allow lossless audio compression scalable to lossy MPEG-4 General Audio coding methods (e.g., variations of AAC).
Multiple-image Network Graphics (MNG) is a graphics file format, published in 2001, for animated images.
In mathematics, a normal number is a real number whose infinite sequence of digits in every positive integer base b is distributed uniformly in the sense that each of the b digit values has the same natural density 1/b, also all possible b2 pairs of digits are equally likely with density b−2, all b3 triplets of digits equally likely with density b−3, etc.
OpenCTM is a 3D geometry technology for storing triangle-based meshes in a compact format.
OptimFROG is a proprietary lossless audio data compression codec developed by Florin Ghido.
Original Sound Quality (OSQ) is an audio file format developed in 2002 by Steinberg Media Technologies GmbH and implemented e.g. in their audio editing software Wavelab 4 (and following releases) for lossless audio data compression.
Pack is a (now deprecated) Unix shell compression program based on Huffman coding.
PAQ is a series of lossless data compression archivers that have gone through collaborative development to top rankings on several benchmarks measuring compression ratio (although at the expense of speed and memory usage).
PCX, standing for PiCture eXchange, is an image file format developed by the now-defunct ZSoft Corporation of Marietta, Georgia, United States.
The number is a mathematical constant.
In mathematics, the pigeonhole principle states that if items are put into containers, with, then at least one container must contain more than one item.
PKWARE, Inc. is an enterprise software company headquartered in Milwaukee, Wisconsin, with offices in the US and UK.
In computing, plain text is the data (e.g. file contents) that represent only characters of readable material but not its graphical representation nor other objects (images, etc.). It may also include a limited number of characters that control simple arrangement of text, such as line breaks or tabulation characters.
Portable Network Graphics (PNG, pronounced or) is a raster graphics file format that supports lossless data compression.
A precompressor is a computer program, which alters file content so that a real lossless compression program will achieve better results than without precompressing.
Prediction by partial matching (PPM) is an adaptive statistical data compression technique based on context modeling and prediction.
PGF (Progressive Graphics File) is a wavelet-based bitmapped image format that employs lossless and lossy data compression.
Randomness is the lack of pattern or predictability in events.
RealPlayer, formerly RealAudio Player, RealOne Player and RealPlayer G2, is a cross-platform media player app, developed by RealNetworks.
In Information theory, redundancy measures the fractional difference between the entropy of an ensemble, and its maximum possible value \log(|\mathcal_X|).
Run-length encoding (RLE) is a very simple form of lossless data compression in which runs of data (that is, sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run.
Shorten (SHN) is a file format used for compressing audio data.
Tagged Image File Format, abbreviated TIFF or TIF, is a computer file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers.
Truevision TGA, often referred to as TARGA, is a raster graphics file format created by Truevision Inc. (now part of Avid Technology).
True Audio (TTA) is a lossless compressor for multichannel 8, 16 and 24 bits audio data.
In cryptography, unicity distance is the length of an original ciphertext needed to break the cipher by reducing the number of possible spurious keys to zero in a brute force attack.
The United States of America (USA), commonly known as the United States (U.S.) or America, is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions.
In data compression, a universal code for integers is a prefix code that maps the positive integers onto binary codewords, with the additional property that whatever the true probability distribution on integers, as long as the distribution is monotonic (i.e., p(i) ≥ p(i + 1) for all positive i), the expected lengths of the codewords are within a constant factor of the expected lengths that the optimal code for that probability distribution would have assigned.
A Usenet newsgroup is a repository usually within the Usenet system, for messages posted from many users in different locations using Internet.
UTF-8 is a variable width character encoding capable of encoding all 1,112,064 valid code points in Unicode using one to four 8-bit bytes.
WavPack is a free and open-source lossless audio compression format.
WebP is an image format employing both lossy and lossless compression.
Wikipedia is a multilingual, web-based, free encyclopedia that is based on a model of openly editable content.
Windows Media Audio (WMA) is the name of a series of audio codecs and their corresponding audio coding formats developed by Microsoft.
WinRAR is a trialware file archiver utility for Windows, developed by Eugene Roshal of win.rar GmbH.
In computing, Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
xz is a lossless compression program and file format which incorporates the LZMA/LZMA2 compression algorithms.
ZIP is an archive file format that supports lossless data compression.
7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives".
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