The U on iTunes - Terms
Lossless Compression
Lossless data compression is a class of
data compression algorithms that allows the exact original data to be
reconstructed from the compressed data. This can be contrasted to lossy
data compression, which does not allow the exact original data to be
reconstructed from the compressed data.
Lossless data compression is used in many applications. For example,
it is used in the popular ZIP file format and in the Unix tool gzip.
It is also often used as a component within lossy data compression
technologies.
Lossless compression is used when it is important that the original
and the decompressed data be identical, or when no assumption can be made
on whether certain deviation is uncritical. Typical examples are executable
programs and source code. Some image file formats, like PNG or GIF, use only
lossless compression, while others like TIFF and MNG may use either lossless
or lossy methods.