Non User
Index: > A B C D E F G H I J K L M N O P Q R S T U V W X Y Z	Business Non User Industries Finance Tax

Home > Data compression

3 See also

3.1 Data compression topics

• algorithmic complexity theory
• information entropy
• self-extraction
• image compression
• multimedia compression
• minimum description length
• universal code s
  • Elias Gamma coding
  • Fibonacci coding
  • Golomb coding
  • Huffman coding

3.2 Compression algorithms

3.2.1 Lossless data compression

• run-length encoding – used by PCX images and PackBits
• dictionary coders
  • LZ77 & LZ78
  • DEFLATE (a combination of LZ77 and Huffman coding) – used by ZIP and gzip files
  • LZW – used by the Unix compress utility (the .Z file format), and GIF files
  • LZMA – used by 7-Zip
• Burrows-Wheeler transform
  • bzip2 (a combination of the Burrows-Wheeler transform and Huffman coding)
• entropy encoding
  • Huffman coding (simple entropy coding)
  • arithmetic coding (more advanced; encumbered by patents as of October 2001)
  • range encoding (simple, intended to approach the performance of arithmetic coding without being patent-encumbered)
• prediction by partial matching
• Unclassified:
  • PAQ (very high compression; competing in the top of the highest compression competitions)
  • LZO (very fast, speed oriented)
  • FLAC (used for lossless audio compression)

3.2.2 Lossy data compression

• discrete cosine transform
  • JPEG (image compression using a windowed cosine transform, then quantization, then Huffman coding)
  • MPEG (the founder of video compression and still in use today, uses DCT and delta)
    • MP3 (a part of the MPEG specification for sound and music compression, using subbanding and MDCT, which is then Huffman coded)
    • AAC (part of the MPEG specification, using MDCT and Huffman coding)
  • Ogg Vorbis (AAC-alike audio codec, designed with a focus on avoiding patent encumbrance)
• fractal compression
  • fractal transform
• wavelet compression
  • JPEG 2000 (image compression using wavelets, then quantization, then Huffman coding)

4 References

• Timothy C. Bell, Ian Witten, John Cleary (1990) Text Compression, Prentice Hall, BooksEnthsiast.com

Politics	Business	Finance

Topics: Data Compression Coding Encoding Huffman Information Audio...

---

DataA datum is a statement accepted at face value (a "given"). Data is the plural of datum''. A large class of practically important statements are measurements or observations of a variable. Such statements may comprise numbers, words, or images. Etymology T Data Encryption StandardThis article is about the DES encryption algorithm. For other uses, see DES (disambiguation). The Data Encryption Standard DES is a cipher (a method for encrypting information) selected as an official Federal Information Processing Standard (FIPS) for the Data warehouseA data warehouse comprises a computing system used to store information regarding an organization's activities in a database. The database design favours reporting on and analysing the data in order to gain strategic information and to facilitate decision Data compressionIn computer science, data compression is the process of encoding information using fewer bits, or information units, thanks to specific encoding schemes. For example, this article could be encoded with fewer bits if we accept the convention that the word DatabaseA database is an information set with a regular structure. Any set of information may be called a database. Nevertheless, the term was invented to refer to computerised data, and is used almost exclusively in computing. Sometimes it is used to refer to no Data setIn statistics, a data set is a set of data consisting of: #a list of research subjects and #the data vector associated with each. See also: Statistical theory Another meaning: Data set (IBM mainframe). Database management system Data structure Database normalization Data General Nova Data compression ratio Data storage device Data access arrangement Data bank Data compaction