[FFmpeg-user] ffmpeg makes some sources darker

[Carl Eugen Hoyos]

Andy Furniss <adf.lists <at> gmail.com> writes:

> I think it's because the master is flagged as rec709 
> but the yuv and I guess hevc aren't.

While this is at least likely (sorry for my original 
comment, I don't know what I looked at), the source 
code seems to disagree: colour_primaries etc. are 
read from both h264 and hevc files and are written 
both when encoding with libx264 and libx265.
You could test to set them with the following:
-color_primaries bt709 -color_trc bt709 -colorspace bt709
(with a faster preset), it shouldn't make a 
difference but who knows...

And please also test with -vcodec x264, Carl Eugen