[FFmpeg-devel] [PATCH 4/4] avcodec/libx265: encode dovi RPUs

[Niklas Haas]

On Tue, 19 Mar 2024 21:59:53 +0000 Cosmin Stejerean via ffmpeg-devel <ffmpeg-devel at ffmpeg.org> wrote:
> 
> 
> > On Mar 19, 2024, at 2:39 PM, Derek Buitenhuis <derek.buitenhuis at gmail.com> wrote:
> > 
> > The reason I never implemented this back when I adde RPU side data is that
> > there is a strong chance of generating broken files.
> > 
> > That's because if we do anything to the video with swscale, etc., we're
> > now encoding RPUs that aren't meant to be applied to that converted video.
> > 
> > For example, this could end up propagating RPUs when the user is tonemapping.
> 
> Would it be possible to only propagate RPUs if the color params are not changing? If there's any change from say PQ to HLG or HLG to PQ or tonemapping then we wouldn't want to propagate RPUs. If the color params are not changing then propagating RPUs by default seems sensible, and perhaps a filter can be added to explicitly clear RPUs if they should not be propagated.

One way to accomplish this would be to simply strip the metadata in all filters
that can change the colorspace. Maybe we should do the same for HDR+ etc.
metadata.

Probably it would make sense to add a common helper function for this. I'll see
what I can do.