[gdal-dev] Re: GDAL custom build (ECW required)

[Frank Warmerdam]

Gilles Bassière wrote:
>> with COMPRESS=JPEG:
>>
>>  Creating output file that is 10000P x 10000L.
>>  Processing input file ortho-dept04-2004-la2e.vrt.
>>  0...10...20...30..gdalwarp: tif_jpeg.c:691: JPEGPreDecode: Assertion
>> `sp->cinfo.comm.is_decompressor' failed.
>>  Aborted

Gilles,

The likely solution to this problem is to build GDAL with
the internal copy of libtiff.  I have fixed a variety of
bugs related to random read/write support in libtiff on
compressed images and some of those fixes have not yet made
it out into distributions copy of libtiff.

> The largest image has a black gap in the middle instead of the actual
> data. The smaller image doesn't show this gap and prove that there is
> actually data in the input dataset.

I suspect black gaps would be due to a problem introduced in
GDAL warp for 1.7.x and only recently fixed.  I would suggest you
build GDAL from either a stable or trunk snapshot so you will
have the fix for this problem with will also appear in 1.7.2 when
it is released.

> Could this be due to wrong values read in the ECW input files?

While I've had lots of problems with ecw over the years, I don't
see any obvious sign it relates to the ecw side of things.

Best regards,
-- 
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