Lossless compression

losslesslossless data compressioncompressiondata compressionlossless audiolossless digital downloadcompresscompressedlossless codeclosslessly compressed
Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data.wikipedia
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Lossy compression

lossylossy data compressioncompressed
By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with improved compression rates (and therefore reduced file sizes).
This is opposed to lossless data compression (reversible data compression) which does not degrade the data.

Zip (file format)

ZIPzip file.zip
For example, it is used in the ZIP file format and in the GNU tool gzip.
ZIP is an archive file format that supports lossless data compression.

Portable Network Graphics

PNG.pngPNGs
Some image file formats, like PNG or GIF, use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods. Because of patents on certain kinds of LZW compression, and in particular licensing practices by patent holder Unisys that many developers considered abusive, some open source proponents encouraged people to avoid using the Graphics Interchange Format (GIF) for compressing still image files in favor of Portable Network Graphics (PNG), which combines the LZ77-based deflate algorithm with a selection of domain-specific prediction filters.
Portable Network Graphics (PNG, pronounced or ) is a raster-graphics file-format that supports lossless data compression.

Huffman coding

HuffmanHuffman codehuffman coded
The primary encoding algorithms used to produce bit sequences are Huffman coding (also used by DEFLATE) and arithmetic coding.
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.

Arithmetic coding

arithmetic coderarithmetic encodingarithmetic code
The primary encoding algorithms used to produce bit sequences are Huffman coding (also used by DEFLATE) and arithmetic coding.
Arithmetic coding is a form of entropy encoding used in lossless data compression.

Entropy (information theory)

entropyinformation entropyShannon entropy
Arithmetic coding achieves compression rates close to the best possible for a particular statistical model, which is given by the information entropy, whereas Huffman compression is simpler and faster but produces poor results for models that deal with symbol probabilities close to 1.
The entropy provides an absolute limit on the shortest possible average length of a lossless compression encoding of the data produced by a source, and if the entropy of the source is less than the channel capacity of the communication channel, the data generated by the source can be reliably communicated to the receiver (at least in theory, possibly neglecting some practical considerations such as the complexity of the system needed to convey the data and the amount of time it may take for the data to be conveyed).

Run-length encoding

RLErun length encodingrun-length encoded
Run-length encoding (RLE) – Simple scheme that provides good compression of data containing lots of runs of the same value
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.

LZ77 and LZ78

LZ77Lempel-ZivLempel-Ziv compression
Because of patents on certain kinds of LZW compression, and in particular licensing practices by patent holder Unisys that many developers considered abusive, some open source proponents encouraged people to avoid using the Graphics Interchange Format (GIF) for compressing still image files in favor of Portable Network Graphics (PNG), which combines the LZ77-based deflate algorithm with a selection of domain-specific prediction filters.
LZ77 and LZ78 are the two lossless data compression algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978.

DEFLATE

deflate-decodedeflateddeflating
The primary encoding algorithms used to produce bit sequences are Huffman coding (also used by DEFLATE) and arithmetic coding. Because of patents on certain kinds of LZW compression, and in particular licensing practices by patent holder Unisys that many developers considered abusive, some open source proponents encouraged people to avoid using the Graphics Interchange Format (GIF) for compressing still image files in favor of Portable Network Graphics (PNG), which combines the LZ77-based deflate algorithm with a selection of domain-specific prediction filters.
In computing, Deflate is a lossless data compression algorithm and associated file format that uses a combination of the LZ77 algorithm and Huffman coding.

Lempel–Ziv–Markov chain algorithm

LZMALZMA2LZMA/LZMA2
Lempel–Ziv–Markov chain algorithm (LZMA) – Very high compression ratio, used by 7zip and xz
The Lempel–Ziv–Markov chain algorithm (LZMA) is an algorithm used to perform lossless data compression.

Xz

xz-compressed
Lempel–Ziv–Markov chain algorithm (LZMA) – Very high compression ratio, used by 7zip and xz
xz is a lossless compression program and file format which incorporates the LZMA/LZMA2 compression algorithms.

Lempel–Ziv–Oberhumer

LZO
Lempel–Ziv–Oberhumer (LZO) – Designed for speed at the expense of compression ratios
Lempel–Ziv–Oberhumer (LZO) is a lossless data compression algorithm that is focused on decompression speed.

Lempel–Ziv–Welch

LZWLempel-ZivLempel-Ziv-Welch algorithm
Lempel–Ziv–Welch (LZW) – Used by GIF images and Unix's utility
Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch.

Lempel–Ziv–Storer–Szymanski

LZSS
Lempel–Ziv–Storer–Szymanski (LZSS) – Used by WinRAR in tandem with Huffman coding
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.

Joint (audio engineering)

joint stereochannel couplingintensity encoded
It is also often used as a component within lossy data compression technologies (e.g. lossless mid/side joint stereo preprocessing by MP3 encoders and other lossy audio encoders).
Lossless codecs such as FLAC or Monkey's Audio use M/S stereo coding because of this characteristic.

Apple Lossless

ALAC.m4aApple Lossless Audio Codec
Apple Lossless (ALAC – Apple Lossless Audio Codec)
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.

GIF

animated GIF.gifgifs
Some image file formats, like PNG or GIF, use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods. Because of patents on certain kinds of LZW compression, and in particular licensing practices by patent holder Unisys that many developers considered abusive, some open source proponents encouraged people to avoid using the Graphics Interchange Format (GIF) for compressing still image files in favor of Portable Network Graphics (PNG), which combines the LZ77-based deflate algorithm with a selection of domain-specific prediction filters. Lempel–Ziv–Welch (LZW) – Used by GIF images and Unix's utility
GIF images are compressed using the Lempel–Ziv–Welch (LZW) lossless data compression technique to reduce the file size without degrading the visual quality.

Dolby TrueHD

TrueHD
Dolby TrueHD
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.

FLAC

.flacFree Lossless Audio CodecFLAC
Free Lossless Audio Codec (FLAC)
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.

Audio Lossless Coding

ALS
Audio Lossless Coding (also known as MPEG-4 ALS)
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.

Bit rate

bitratedata ratedata transfer rate
By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with improved compression rates (and therefore reduced file sizes).
A theoretical lower bound for the encoding bit rate for lossless data compression is the source information rate, also known as the entropy rate.

DTS-HD Master Audio

DTS Master "CoreDTS-HDDTS-HD MA 5.1
DTS-HD Master Audio
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.

Meridian Lossless Packing

MLPlosslessMLP (Meridian Lossless Packing)
Meridian Lossless Packing (MLP)
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

APE.apeMonkey's Audio (APE)
Monkey's Audio (Monkey's Audio APE)
Monkey's Audio is an algorithm and file format for lossless audio data compression.

TTA (codec)

TTATrue Audio.tta
TTA (True Audio Lossless)
True Audio (TTA) is a lossless compressor for multichannel 8, 16 and 24 bits audio data.