2010.12.22 16:20 "[Tiff] [ANNOUNCE]: LZMA2 codec", by Andrey Kiselev
I would like to announce that the code implementing LZMA2 compression has been checked in the libtiff's development branch (4.x). tiffcp utility can utilize this new compression method (use '-c lzma' switch). Encoder applies delta filter internally, but you still can use predictor value 2 or 3. Sometimes it helps to get even better compression ratios. LZMA2 seems to be the best comression method (comparing to LZW and Defalte), though the slowest one. Worth a try if you are hunting for bytes.
The compression code for LZMA2 is 34925.
Andrey V. Kiselev