Data Compression

Data compression is a useful way of reducing the size of data that can be stored on a computer. It is also used for many purposes and can be achieved in many ways. Smaller data take up less room on a hard disk and makes faster data transfer over a network. Data compression involves applying algorithms to data that has some unnecessary repetitive bits. Compressed data is needed to be decompressed to be used, to restore missing bits and reconstitutes the complete file. Data compression can be used with text files, graphics, multimedia files, and executable programs.


The data compression can be classified in two types, lossless and lossy. Lossless data compression algorithms usually makes data smaller by looking for patterns that can be written more concisely. It exploit statistical redundancy to represent the data more concisely without error. Lossy compression makes data smaller by removing some excess data but still makes acceptable result of data. This data compression provides way of obtaining the best quality for a given amount of compression.

Data compression for files on computer is a lossless type of compression. Each compression format used different technique of compressing files and the type of compression used can be identified by the compressed format file type. Popular file compression tools are 7-Zip and WinRar. Zip is compatible with a wide range of compression formats, and WinRar is the only software able to create compressed .rar files.

Data compression for multimedia files such as audio, images and video can be lossless or lossy. Images and audio compression can be either lossless or lossy, depending on the compression format used. Although the most commonly used in audio is lossy due to the substantial decrease in file size with little noticable change of sound, and its commonly format used is MP3. The compression creates a smaller file at lower audio quality from the original recording. For images, lossless compression is suited with straight edges, sharp contrast or technical information images, while lossy compression is suited for images or photographs with gradual changes. For video, primarily the data compression is lossy. The changes from former tracks are between image frame of a video, and these changes are often small.

Most types of computer data and files are fairly redudant, wherein same informations are listed over and over again. These file compression programs simply get rid of the redundancy by listing the information once then refers back to it whenever it appears in the original data. Some data compression programs allow the user to choose the depth of compression, so make sure not to over compress or even compress the data twice, because the compressed data must be decompressed for it to be used again, and this extra processing may be detrimental to some applications of the data.

Data Compression