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May 2005
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2005.05.25 13:31 "Re: Another libtiff+libjpeg problem", by Jean-yves Le Ridant
KW> if your after a slightly better approximation but not too slow when KW> doing bit depth promotion you should fill the bottom bits with the KW> upper bits... KW> e.g. 12 bits to 16 ... KW> 12 bits names BA9876543210 ->> BA9876543210BA98 KW> The above being a bit shift KW> out := (in << 4) | (in >> 8) KW> 8 bits 76543210 ->> 7654321076543210 KW> it works and ensures that peak input is mapped to peak output. :-)) Yes but ...., unsigned shift is perfect for a and b of ICCLAB, and signed shift would be right for those of CIELAB ( and guys have strange ideas as jpeg compressing of CIELAB ...) :-) No hope, really handling 16 bits is a job, and would be better handled by jpeglib interface, mixed with/in existing tables. So at this point it's obstensibely a quickwatch. -- Jean-Yves