In the context of ITWissen, the term decompression stands for the unpacking of compressed files. Decompression thus forms the counterpart of compression, in which redundant characters of a file are eliminated.
Decompression attempts to convert a compressed file - which may be a text, audio, graphics or video file - back into a file that is identical to the file before compression, or at least very similar to it in terms of the information it contains. The distinction is important in that there is lossless compression and there is also lossy compression.
With lossless compression, the signals can be completely reconstructed. It is different with lossy compression, which is used to compress audios, graphics and videos. With this decompression, the signals cannot be restored to the original state that the corresponding file had before compression. With each decompression, an attempt is made to reconstruct the original signal as closely as possible. How close the decompressed signal is to the original signal depends on the compression method and the degree of compression.