[FFmpeg-user] DNG images

[Paul B Mahol]

On Tue, Oct 13, 2020 at 10:06:37PM +0200, Michael Koch wrote:
> Am 11.10.2020 um 21:07 schrieb Michael Koch:
> > Am 11.10.2020 um 20:56 schrieb Paul B Mahol:
> > > On Sun, Oct 11, 2020 at 07:37:25PM +0200, Michael Koch wrote:
> > > > I tested all 4 DNG images again with the latest FFmpeg version
> > > > (Gyan's build
> > > > from today).
> > > > I tested with and without zscale filter. All tests failed. When
> > > > testing with
> > > > IrfanView, all DNG input images seem to be ok.
> > > > 
> > > Your issues is that you do not know how to use zscale properly.
> > > 
> > > DNG decoding is just fine, what is missing is colorspace stuff in
> > > swscale,
> > > for proper display.
> > 
> > Can you please give an example for the correct zscale options?
> > 
> 
> Finally I found a command line that converts DNG (from Adobe DNG converter)
> to JPG with a more or less acceptable result:
> 
> ffmpeg -i IMG_3459.dng -vf zscale=t=linear,tonemap=gamma:param=1.85,tonemap=linear:param=64,colorlevels=rimin=0.0:gimin=0.0:bimin=0.0:rimax=0.53:gimax=1:bimax=0.57

This is simple wrong. You do not set output trc at all. Make sure to use right
input pixel format prior to calling zscale as it does not support bayer formats.