Apr 29
Dynamic Tone Mapping - Banding / Posterisation
Just updated to the new RBE Beta. I am not sure if this was present on the previous stable FW most likely it is though.Basically I found a scene where DTM causes quite significantly ugly banding and posterisation, usually because the curve is being too agressive in some manner. I made a post on AVS showing images, ill share the images here anyway, but check the post for a better description. The test scene is here, please check in your labs and recreate the issue, I would like to work with you to come up with a DTM which has a 'calm' image. I dont like overly sharpened and agressive DTM.Some notes. RBE Reduction was OFF, DBLE was OFF. No image enhancements are on, HDR10, Movie colour temp. Iris modes do not affect it.If I turn off DTM the issue completely goes away and the image has nice gradients again. This issue does extend beyond only this shot, its in other content too, content which has very high encoded nits (thousands of nits). We need to be very careful we dont clip colour because thats one way this could be happening. Its possible having a control for extra HDR Highlight Desaturation may solve this issue, please consider giving us a special beta with many more DTM options so we can collectively find the best settings, I really wish to help find the best DTM possible. I spent years helping MadVR with this exact thing. As you have highly saturated colours which are encoded really bright and you tone map them, you can clip the colour gamut well outsisde of BT2020, its possible this is happening. Usually DTM will have a level of desaturation required on the very brightest pixels. We may need to improve that... The test scene is here, note this video is actually still frames in HDR pulled directly from the UHD Bluray file. This is a good way to test HDR tonemapping with an exact frame from a film. There is 1 shot every second.https://www.dropbox.com/scl/fi/r036cjrsgyutc1i61w7nk/Goblet-… discussionhttps://www.avsforum.com/threads/xgimi-pushes-into-premium-projectio…
In Progress
