Ticket #1939 (closed defect: fixed)
Conversion of paletted PNG to ECW does not work
|Reported by:||jcrepetto||Owned by:||mloskot|
|Severity:||normal||Keywords:||ecw color table expansion|
|Cc:||warmerdam, rouault, klokan|
When I convert a paletted PNG file to ECW, the resulting image is almost black, as if the compression was made using the indexes instead of the real colours.
gdal_translate -of ECW -co "TARGET=94%" -co "DATUM=NTF" -co "PROJ=LM1FRA2D" -a_ullr 970000 1860000 980000 1850000 test.png test.ecw
There is no problem with a true colour PNG image.
- Either GDAL should do the 8-bit to 24-bit conversion as part of the format translation (for convenience and to save on temporary disk space)
- Or at least produce an error message that paletted files are not supported, and stop. GDAL should not produce a wrong result, it would save a lot of time to users.
Note : This topic has been discussed on the GDAL-dev ML, on 19 Dec 2006 and 3 Jul 2007.