[gdal-dev] JPEG/PNG 12 bits GDAL python

[jratike80]

Hi,

With my GDAL 3.1.4 from OSGeo4W converting a single band Float32 DEM file
into JPEG compressed TIFF and into plain JPEG succeeded with these commands:

gdal_translate L2431.tif -co COMPRESS=JPEG -ot uint16 -co NBITS=12 out.tif
gdal_translate L2431.tif -of JPEG -ot uint16 -co NBITS=12 out.jpg

I have never played with 12 bit JPEGs before. The documentation was not very
clear to me and I am not sure if it is essential to first define the data
type into uint16 and then limit the number of NBITS into 12.
But without using -ot uint16 I got messages like

Warning 6: Only NBITS=16 is supported for data type Float32
Warning 1: NBITS=32 is invalid for data type UInt16. Using NBITS=16
ERROR 1: JPEGSetupEncode:BitsPerSample 16 not allowed for JPEG

Warning 6: driver JPEG does not support creation option NBITS
0Warning 6: JPEG driver doesn't support data type Float32. Only eight and
twelve bit bands supported (Mk1 libjpeg).

I wonder if there is any way for the user to find out if their GDAL is
compiled with 12 bit JPEG support.

-Jukka Rahkonen-



GDAL - Dev mailing list wrote
> Hello and thank you in advance,
> 
>  
> 
> Im trying to generate png and jpeg 12 bits images from a GTiff single band
> file with no success. I know is there a way to generate 12 bits images in
> the GDAL command line as I have seen in some examples (“gdal_translate
> mandril_rgb.tif -co COMPRESS=JPEG -co PHOTOMETRIC=YCBCR -co NBITS=12
> out.tif”) but trying it with my singlebands tif files it only generates a
> black image (with PHOTOMETRIC set to MINISBLACK). Is it only a method for
> rgb files?
> 
> Searching in the python API I only can find gdalconst for 16, 32 and 64
> bits
> formats. Is there a way to do the same with 12 bits files?
> 
>  
> 
> Kind regards
> 
>  
> 
> 
>  <http://www.solute.es/> 
> 
> 
> Jesús Maria Morán Rosado
> Project Engineer
> 
> Av. Cerro del Águila, 3, 28703 S.S. de los Reyes, Madrid
> 
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