Even Rouault <even.rouault <at> mines-paris.org> writes: > > Hi Even, > > > > Sorry, I must have been unclear. The question was about writing out a real > > JPEG file, not JPEG compressed TIFF > > Ah my fault. I read too fast. > > > The command gdal_translate -of jpeg rgba_in.tif jpeg_out.jpg creates a jpeg > > file with this gdalinfo > > > > C:\Jukka>gdalinfo jpeg_out.jpg > [...] > > SOURCE_COLOR_SPACE=CMYK > > My guess was right actually. In JPEG there's no way, AFAIK, to define RGBA. 4 > bands JPEG are assumed to be in CMYK color space. >
Thanks, that makes sense. However, the result is somehow surprising and I guess that in most cases unusable for the user. I wonder if it would be good to print something like "WARNING. Encountered 4 source bands, assuming CMYC color space". Behaviour is not very easy to understand by reading the driver page http://www.gdal.org/frmt_jpeg.html When I try to look at the situation as a QGIS user sees it, it feels like there is a bug somewhere but I can't say exactly where. However, I do not believe that any average QGIS user can have success with converting their RGBA tiffs into jpeg format even it is possible by editing gdal_translate command manually. -Jukka- _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
