12 Facts About LZMA

LZMA uses a dictionary compression algorithm, whose output is then encoded with a range encoder, using a complex model to make a probability prediction of each bit.

The main innovation of LZMA is that instead of a generic byte-based model, LZMA's model uses contexts specific to the bitfields in each representation of a literal or phrase: this is nearly as simple as a generic byte-based model, but gives much better compression because it avoids mixing unrelated bits together in the same context.

In LZMA compression, the compressed stream is a stream of bits, encoded using an adaptive binary range coder.

LZMA data is at the lowest level decoded one bit at a time by the range decoder, at the direction of the LZMA decoder.

LZMA decoder is configured by an "properties" byte and a dictionary size.

Each LZMA compressed run can have a different LZMA configuration and dictionary.

Since LZMA uses very large dictionaries to improve compression, simply scanning the whole dictionary would result in an encoder too slow to be practically usable, so sophisticated data structures are needed to support fast match searches.

Some old LZMA encoders supported a data structure based on Patricia tries, but such support has since been dropped since it was deemed inferior to the other options.

LZMA state is reset only in the first block, if the caller requests a change of properties and every time a compressed chunk is output.

The LZMA properties are changed only in the first block, or if the caller requests a change of properties.

LZMA implementation extracted from 7-Zip is available as LZMA SDK.

LZMA2 compression, which is an improved version of LZMA, is the default compression method for the.