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May 2004
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2004.05.17 13:59 "Re: Tiff compression and bits per sample", by Andrey Kiselev
On Mon, May 17, 2004 at 12:05:48PM +0000, mayankg@iiitb.ac.in wrote: > 1. I want know whether all kinds of compression schemes possible > within a TIFF file, are supported by libtiff? Yes, all schemes, defined in the 6.0 specifications and later addendum are implemented. > 2. Do we need to install separate patches for supporting some/all of > those? JPEG and Deflate compressions require external libraries: libjpeg and zlib. > 3. If there are any licensing issues with installing those patches? > (e.g. I have come to know that for supporting lzw compression we need > to install a patch and also need to buy out a license for using the > same) It is completely depend on your country laws. If software patents are possible in your country and one of the compression algorithms is patented and patent still valid --- it can be a problem for you. But you should do your own patent investigation to finally clarify that. BTW, Unisys LZW patent already expired in the USA and will expire shortly in some other countries. > 4. Apart from 8, 16, 32 and so on, bits per sample TIFF images, are > there any other bit per sample TIFF images possible e.g. 1, 2, 4, 9, > 17 and like wise other bits per sample images. 1- and 4-bits per pixel data are possible and widely used. Generally speaking, other bit depths are possible too, but does it have any practical reason? Such images will be incompatible with the most part of commonly used software tools. Of course, for in-house usage you can consider applying any bit depth you need. Andrey -- Andrey V. Kiselev Home phone: +7 812 5274898 ICQ# 26871517