Ticket #4185 (closed defect: invalid)
some problem with gdal_translate jpeg 12bits
|Reported by:||tunofilho||Owned by:||warmerdam|
hi, I was using gdal_translate in qgis 1.7.0 and I was looking for how to transform a raster of srtm raster .tif to srtm raster .jpeg 12bits, but there is a problem in modification of libjpeg to 12 bits. The transformation didn't obey the change of scale 16bits to 12bits, in other words, value of pixels over 4095 in 16 bits have been cut to value 4095 in 12bits. The correct would be adjust scale 16bits to 12bits. In algorithm of jpeg, the matrix 8x8 must be subtract by 128(8bits) or 2048(12bits). In attach there is a light of signal of srtm raster .tif and .jpeg (gdal_translate).