AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2006.03.04 03:05 "[Tiff] LZW Compression with 16-bit TIFF", by Frank Peters
2006.03.04 03:12 "Re: [Tiff] LZW Compression with 16-bit TIFF", by Bob Friesenhahn
2006.03.04 03:33 "Re: [Tiff] LZW Compression with 16-bit TIFF", by Frank Peters
2006.03.04 06:27 "Re: [Tiff] LZW Compression with 16-bit TIFF", by Bob Friesenhahn
2006.03.04 12:21 "Re: [Tiff] LZW Compression with 16-bit TIFF", by Joris

2006.03.04 03:05 "[Tiff] LZW Compression with 16-bit TIFF", by Frank Peters

Hello,

My problem concerns the compression of tiff files using the command:

tiffcp -c lzw:2 file.tif file_compressed.tif

With 8-bit tiff files this compression reduces the the file size by about 30%.

With 16-bit tiff files, however, the compressed file is actually LARGER. For example, using the above command a 36 megabyte 16-bit tiff file will "compress" to about 46 megabytes. For the other possible options, "-c lzw:1" and "-c lzw", the results are essentially the same. The compressed file is always significantly larger.

If I use "-c zip" as the option, 16-bit files are reduced somewhat (from 36 Mb to 34 Mb).

Is there possibly a bug in the 16-bit lzw code or does the fault lie elsewere?

Frank Peters