JP2KAK : offset in lossless unsigned int (16 bits)

[pinchonn]

There is a problem with creating a lossless JPEG2000 image with JP2KAK (kakadu) from an unsigned int image : the output image has an +32768 offset. This offset seems to be constant.

The test image is an unsigned int TIFF image (see attachment).

I tried last GDAL versions : 1.8.1 and 1.9.0
Kakadu version is 6.4.1 (latest).
Platform is Linux Red Hat 5 64 bits.

To reproduce the bug :

gdal_translate -of JP2KAK -co QUALITY=100 input.tif out_gdal_translate.jp2

Using kakadu tools there is no problem :

kdu_compress -i input.tif -o out_kdu_compress.jp2 Creversible=yes Clayers=16

(Creversible is used instead of QUALITY=100)

[pinchonn]

input image

[pinchonn]

ouput image created with gdal_translate

[pinchonn]

output image created with kdu_compress

[GMaillet]

I had the same problem with 16-bit unsigned images. Pending an official correction I fix the problem by using 32 bit kdu_line_buf for reversible GDT_UInt16 images and substract the 32768 constant in the file frmts/jp2kak/jp2kakdataset.cpp.

[GMaillet]

patched file to fix this problem

[Even Rouault]

trunk r26626 "JP2KAK: fix creation of unsigned int16 with reversible compression (patch by GMaillet, #4050)"