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March 2005
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2005.03.22 22:28 "Re: tif_jpeg.c and 12bit JPEG Files", by Frank Warmerdam
On Tue, 22 Mar 2005 15:59:02 -0600 (CST), Bob Friesenhahn wrote: > I just verified your updates against IJG JPEG 6b (not the Mk1 version) > built at 12 bits and am happy to report that it almost works! I say > *almost* since the image appears as if the red and green samples have > been interchanged. Trees and grass in the image are shown as red. Bob, Hmm, odd. I tried with a 12bit jpeg encoded TIFF file with the IJG 6b code build in 12bit mode, and the colors displayed fine. I wonder if this is a platform endianness issue. Are you working on a big endian system? Can you provide your file? Unfortunately I cannot provide my test data as it is under NDA, and I can't generate data since the write paths are not working. > Performance seemed slower than expected, but then again my test image > is 125MB, tiled, and multi-frame encoded (7680x13824 largest frame) so > that might explain the slowness. > > Did you include a writer-path in your updates? I did no updates to the JPEGEncode() function so I would not expect it to work properly for 12bit images. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent