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When audio files are to be processed, either by further compression or for editing, it is desirable to work from an unchanged original (uncompressed or losslessly compressed). Processing of a lossily compressed file for some purpose usually produces a final result inferior to the creation of the same compressed file from an uncompressed original.
gzip is a file format and a software application used for file compression and decompression.The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by GNU (from which the "g" of gzip is derived).
In fact, if we consider files of length N, if all files were equally probable, then for any lossless compression that reduces the size of some file, the expected length of a compressed file (averaged over all possible files of length N) must necessarily be greater than N. [citation needed] So if we know nothing about the properties of the data ...
This means that compressed archives with the UC2 file extension can hold almost 1 million files. .uca PerfectCompress [17] Windows: Windows: No Based on PAQ, RZM, CSC, CCM, and 7zip. The format consists of a PAQ, RZM, CSC, or CCM compressed file and a manifest with compression settings stored in a 7z archive. .uha UHarc DOS/Windows: DOS/Windows ...
The Zstandard command-line has an "adaptive" (--adapt) mode that varies compression level depending on I/O conditions, mainly how fast it can write the output. Zstd at its maximum compression level gives a compression ratio close to lzma, lzham, and ppmx, and performs better [vague] than lza or bzip2.
Files can be returned to their original state using uncompress. The usual action of uncompress is not merely to create an uncompressed copy of the file, but also to restore the timestamp and other attributes of the compressed file. For files produced by compress on other systems, uncompress supports 9- to 16-bit compression.
Thus, a representation that compresses the storage size of a file from 10 MB to 2 MB yields a space saving of 1 - 2/10 = 0.8, often notated as a percentage, 80%. For signals of indefinite size, such as streaming audio and video, the compression ratio is defined in terms of uncompressed and compressed data rates instead of data sizes:
Compressed file formats often feature both compression (storing the data in a small space) and archiving (storing multiple files and metadata in a single file). One can combine these in two natural ways: compress the individual files, and then archive into a single file; archive into a single data block, and then compress.