LzmaCompress ------------ LZMA Encoder will use default values for any parameter, if it is -1 for any from: level, loc, lp, pb, fb, numThreads 0 for dictSize level - compression level: 0 <= level <= 9; level dictSize algo fb 0: 16 KB 0 32 1: 64 KB 0 32 2: 256 KB 0 32 3: 1 MB 0 32 4: 4 MB 0 32 5: 16 MB 1 32 6: 32 MB 1 32 7+: 64 MB 1 64 The default value for "level" is 5. algo = 0 means fast method algo = 1 means normal method dictSize - The dictionary size in bytes. The maximum value is 128 MB = (1 << 27) bytes for 32-bit version 1 GB = (1 << 30) bytes for 64-bit version The default value is 16 MB = (1 << 24) bytes. It's recommended to use the dictionary that is larger than 4 KB and that can be calculated as (1 << N) or (3 << N) sizes. lc - The number of literal context bits (high bits of previous literal). It can be in the range from 0 to 8. The default value is 3. Sometimes lc=4 gives the gain for big files. lp - The number of literal pos bits (low bits of current position for literals). It can be in the range from 0 to 4. The default value is 0. The lp switch is intended for periodical data when the period is equal to 2^lp. For example, for 32-bit (4 bytes) periodical data you can use lp=2. Often it's better to set lc=0, if you change lp switch. pb - The number of pos bits (low bits of current position). It can be in the range from 0 to 4. The default value is 2. The pb switch is intended for periodical data when the period is equal 2^pb. fb - Word size (the number of fast bytes). It can be in the range from 5 to 273. The default value is 32. Usually, a big number gives a little bit better compression ratio and slower compression process. numThreads - The number of thereads. 1 or 2. The default value is 2. Fast mode (algo = 0) can use only 1 thread.