[FFmpeg-user] ffmpeg makes some sources darker

[Andy Furniss]

Andy Furniss wrote:

> Strange, unless there is something in the pngs that causes a
> different viewer to produce different output.
>
> I looked again (display from ancient imagemagic) and can't see any
> difference - psnr/ssim agree.
>
> The pngs are not the same md5sum wise
>
> md5sum frame1-yuv-709.png frame1-master.png
> 1c086ed015ebe05aa1cfc66d9fe754a3  frame1-yuv-709.png
> 91ab580b1db4361fcceadaffd24930bd  frame1-master.png

The obvious difference between the pngs is master is bigger by 60 bytes
and it has extra info in it, I can see with ffmpeg -i ... that SAR and
DAR are shown - nothing about 709 but maybe that's in there as well?

I tried making another png from yuv using out_color_matrix as well as
in_color_matrix, but it produced the same file (md5sum) as just
in_color_matrix.