[FFmpeg-devel] SDR->HDR tone mapping algorithm?

[Harish Krupo]

Hello,

We are in the process of implementing HDR rendering support in the
Weston display compositor [1] (HDR discussion here [2]). When HDR
and SDR surfaces like a video buffer and a subtitle buffer are presented
together, the composition would take place as follows:
- If the display does not support HDR metadata:
  in-coming HDR surfaces would be tone mapped using opengl to SDR and
  blended with the other SDR surfaces. We are currently using the Hable
  operator for tone mapping.
- If the display supports setting HDR metadata:
  SDR surfaces would be tone mapped to HDR and blended with HDR surfaces.

The literature available for SDR->HDR tone mapping varies from simple
linear expansion of luminance to CNN based approaches. We wanted to know
your recommendations for an acceptable algorithm for SDR->HDR tone mapping.

Any help is greatly appreciated!

[1] https://gitlab.freedesktop.org/wayland/weston
[2] https://lists.freedesktop.org/archives/wayland-devel/2019-January/039809.html

Thank you
Regards
Harish Krupo