[PATCH] Build overview for Jpeg-in-TIFF file only if GDAL uses libtiff >= 4.0

[pcav]

Pyramids cause tiff files to become reddish, and the lower right quadrant is not completed

[ersts]

Could you provide a little more background? 1) pyramids were built internal or external? 2) which resampling method? 3) is the tif paletted? 4) what OS and version of GDAL are you using?

thanks

[pcav]

1) External pyramids seem ok. Internal cause a crash, and the resulting tiff is reddish with the missing tile 2) average 3) GDT_Byte - Eight bit unsigned integer Image Structure Metadata:

COMPRESSION=JPEG INTERLEAVE=PIXEL

4) tested with Debian Lenny, both on 32 and 64 bit, plus 64 bit Fedora; GDAL 1.5.2-3

[ersts]

I was able to reproduce. It seems to be size dependent. Pyramids built ok on an 80x80 image but crashed on 8000x8000.

When it crashes I get

--> tif_jpeg.c:691: JPEGPreDecode: Assertion `sp->cinfo.comm.is_decompressor' failed.

So it is a GDAL problem. Will have to look through their tickets to see if this is a known problem.

[pcav]

Strange however: apparently GDAL does not crash on the same task when called from the command line

[ersts]

I can reproduce the crash from the command line as well.

looks like it is a know problem, that has been closed but not really fixed  http://trac.osgeo.org/gdal/ticket/2033

May have to consider not allowing pyramids to be build for JPEG compressed tifs.

[ersts]

-internal pyramid building with compress rasters, specifically JPEG compress is no longer enabled.

This can be re evaluated after libtiff 4+ comes out.

[rouault]

Ticket #2033 was closed because the fix for it went to libtiff 4.0 branch, but libtiff < 4.0 has still the issue.

So I'm attaching a patch that enables to build safely overviews on Jpeg files or Jpeg-in-TIFF file by checking that GDAL uses libtiff >= 4.0. The "official" trick to do that is searching 'BIGTIFF' in the creation options of the GTiff driver.

[ersts]

The patch has been applied, r11187.

Thanks rouault.