Reducing the amount of data required to recreate an original file or graphic Compression is frequently used to reduce the transmission time of media and files across the Web
Removal of redundant information from a file or data stream, to reduce its size, the storage space it needs, or the time needed for transmission Lossy compression actually discards information that is considered not essential, and is only appropriate for data like images or sound
the reduction in size of data in order to save space or transmission time Since graphic image file formats are usually very large files, they are usually designed to compress information as much as possible
applying pressure encoding information while reducing the bandwidth or bits required the process or result of becoming smaller or pressed together; "the contraction of a gas on cooling
A means of reducing the size of files to allow quicker transmission, or to take up less space you need a program such as WinZip to compress and uncompress the files
In wireless microphones, the process of reducing the dynamic range of the audio signal by a factor of 2: 1 via a logarithmic compressor for transmission In general audio use, a circuit to reduce circuit gain by a variable amount when the output begins to exceed some preset maximum
Shrinking the file size of a captured image down to a more manageable size Most digital cameras use some type of compression An uncompressed image can be very large (between 8MB and 16MB); compression fits more images in the same space with limited quality loss
When storing information in digital form, it is often possible reduce the amount of space required by exploiting regular patterns in the data For example, documents written in English frequently contain "the" A compression system might notice this fact and represent the complete word "the" (24 bits) with a shorter code A picture containing your friend's face plus a lot of blue sky could be compressed if the upper region were described as "a lot of blue sky" All popular Web image, video, and sound formats incorporate compression
A technique used to considerably reduce the size of a file without losing any of the original information The compression process alters the content of the file but this can and is completely recovered by reversing the process
Data Compression is a process that reduces the size of a file by "eliminating" any redundant data Many different schemes of compression exist for audio, computer data, video etc Compressing a file saves storage space and allows for faster transmission of data Decompression is the reverse process to restore data to its original form [BACK]
Reduction of the size of digital data files by removing redundant and/or non-critical information ("data" being the elements of video, audio and other "information") Digital TV in the U S would not be possible without compression
A process that reduces the file size for processing, storage, transmission, and display Compression may be lossless (e g , CCITT) or lossy (JPEG) The quality of the image may be affected by the compression techniques used and the level of compression applied
In MIDI-computing, the process of compression and expansion refers to changing the range of a song Compression makes the loud parts softer, the soft parts louder
It is often possible to remove redundant information or capitalize on patterns in data to make a file smaller Usually when a file has been compressed, it cannot be used until it is uncompressed Image files are common exceptions, though, as many popular image file formats have compression built-in
A technique used to increase the number of bits per second sent over a data link by replacing often-repeated characters, strings, and command sequences with electronic code When this compressed data reaches the remote end of the transmission link, the coded data is replaced with the actual uncompressed data
Reduction in the size of digital materials by removing redundancy or by approximation; lossless compression can be reversed; lossy compression can not be reversed since information is lost by approximation
Reducing the size of data to be stored or transmitted in order to save transmission time, capacity, or storage space Some software programs accomplish this by stripping color graphics and other "non-essential" data identifiers from the data stream (Back to top )
1 A method to store text, data, or images in fewer bits Rather than store every pixel of a blue square, the computer could store only one blue pixel and the dimensions of the square Several compression standards exist: JPEG, JBIG, MPEG, GIF, TIFF, PICT, ZIP 2 Lossy compression A form of compression in which some data is discarded to allow much smaller file sizes In image compression, lossy techniques such as those uses in the JPEG format D Return to top
The coding of files to storage space or transmission time Most commonly used files of text, images, sound, or video can be converted into files of fewer bits These compressed files can then be expanded to the original form for display or play Many compression algorithms exits Some compressions are better suited on one type of file than for others Commonly used image compression methods are JPEG, and GIF There are special compression methods for sound and video (e g , MPEG compression) files Some compression methods are used for files without regard to the kind of data represented Common general compression methods include zip and pkzip for DOS based systems, stuffit for Macintosh® operating systems, andcompress (using gzip) for UNIX operating systems Two or more compressed files may be combined into an archive file using compression programs such as tat or zip
Digital data can be compressed by encoding repeatable patterns of binary 0's and 1's Compression depends entirely on the type of file and compression algorithm used, and can be the result of a software algorithm or hardware circuitry The more patterns that can be found, the more that data can be compressed Text can generally be compressed to about 40% of its original size, and graphics files from 20% to 90%
The re-encoding of data to make it smaller Most image file formats use compression because image files tend to be large and consume large amounts of disk space and transmission time over networks
Compression is the process by which image data is reduced to require less storage space Employing compression is particularly important when saving gray-scale or color images because of their large size Software algorithms search the raster image to build a greatly condensed (from a file storage perspective) format of the image In the case of CCITT Group IV, the file size reduction is about 25: 1 The actual compression factor is greatly dependent upon the quality of the scan and upon the density of the information
Decreasing the size of stored information by reducing the representation of the information without significantly diminishing the information itself, usually by removing redundancies Requires decompression upon retrieval Lossless compression allows the original data to be recreated exactly Lossy compression sacrifices some accuracy to achieve greater compression