2011.01.01 13:41 "[Tiff] Regression in libtiff 4.0 CVS when creating a JPEG RGB contig", by Even Rouault

Hi Lee,

Happy New Year to begin with. Now, less funny things ;-) I've seen a regression in GDAL (http://trac.osgeo.org/gdal/ticket/3887) that I tracked down to be caused by the following change in libtiff:

2010-12-14 Lee Howard <faxguy@howardsilvan.com>

        * libtiff/tif_jpeg.c: reduce usage of JCS_UNKNOWN in order
        to improve compatibility with various viewers
        submitted by e-mail from Dwight Kelly <dkelly@apago.com>

--- frmts/gtiff/libtiff/tif_jpeg.c.ok 2011-01-01 14:10:57.226381933 +0100
+++ frmts/gtiff/libtiff/tif_jpeg.c 2011-01-01 14:11:06.736240426 +0100

@@ -1701,8 +1701,15 @@
                        sp->cinfo.c.comp_info[0].h_samp_factor = sp->h_sampling;
                        sp->cinfo.c.comp_info[0].v_samp_factor = sp->v_sampling;
                } else {
- sp->cinfo.c.in_color_space = JCS_UNKNOWN;
- if (!TIFFjpeg_set_colorspace(sp, JCS_UNKNOWN))
+ if (td->td_photometric == PHOTOMETRIC_MINISWHITE || td-
>td_photometric == PHOTOMETRIC_MINISBLACK)

sp->cinfo.c.in_color_space = JCS_GRAYSCALE;
if (td->td_photometric == PHOTOMETRIC_RGB) else
= JCS_RGB;sp->cinfo.c.in_color_space

+ else if (td->td_photometric == PHOTOMETRIC_SEPARATED && td-
>td_samplesperpixel == 4)

sp->cinfo.c.in_color_space = JCS_CMYK;

else
= JCS_UNKNOWN; sp->cinfo.c.in_color_space
(!TIFFjpeg_set_colorspace(sp, if

(sp->cinfo.c.in_color_space == JCS_RGB)? JCS_YCbCr: sp->cinfo.c.in_color_space))

                                return (0);
                        /* jpeg_set_colorspace set all sampling factors to 1 */
                }

This can be also reproduced with tifcp:

$ ./tools/tiffcp in.tif out.tif -c jpeg:r -p contig

where in.tif is a 3 band image (uncompressed, since for some reason tiffcp doesn't like compressed images as source)

and then:

$ ./tools/tiffinfo out.tif -D
TIFF Directory at offset 0x1274 (4724)
  Image Width: 128 Image Length: 128
  Tile Width: 256 Tile Length: 16
  Bits/Sample: 8
  Sample Format: unsigned integer
  Compression Scheme: JPEG
  Photometric Interpretation: RGB color
  Orientation: row 0 top, col 0 lhs
  Samples/Pixel: 3
  Planar Configuration: single image plane
  JPEG Tables: (289 bytes)