Compression+and+decompression

=Lossy= Refers to data compression techniques in which some amount of data is lost. Lossy compression technologies attempt to eliminate redundant or unnecessary information. Most video compression technologies use a lossy technique.

=Lossless= Refers to data compression techniques in which no data is lost. For most types of data, lossless compression techniques can reduce the space needed by only about 50%. For greater compression, one must use a lossy compression technique. Note, however, that only certain types of data -- graphics, audio, and video -- can tolerate lossy compression. You must use a lossless compression technique when compressing data and programs.

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