You just sent 6 consecutive messages and 6.2MB of data to a mailinglist.
A mailing list is neither a blog nor a file sharing tool.
To enable OpenCL you have to restart darktable, so the libraries can be
loaded. This information can be found in the blogpost you linked, among
many other sources.
Se
Okey, the YCbCr colorspace is the issue here. Different compression
modes make no difference, but exporting them to rgb24 works.
I found a thread where ffmpeg devs (i guess) claim their YCbCr tifs
are correct but several programms would read them wrong.
I have an other file which darktable manages
