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The hdr-compute-peak changes the brightness unaturally. #5960
mpv version and platform
Play a HDR 4K 60fps video.
The brightness changes naturally.
It changes the brightness so suddenly, and the range seems to be too big, sometimes the graphic is vivid, sometimes it's too dim, and they happens in the same scene.
How it looks like: https://0x0.st/spJO.mkv
Samsung Travel With My Pet HDR UHD 4K Demo
changed the title from
The hdr-compute-peak makes the video suddenly darker and suddenly brighter.
The hdr-compute-peak makes changes the brightness unaturally.
Jul 2, 2018
The problem in your clip is the "SAMSUNG" logo at the top right. It's stupidly bright, way brighter than the rest of the clip. Clearly some mastering engineer thought it a good idea to blast the user with super-highlights in the hope that it would somehow be registered as readable text.
The moment the SAMSUNG logo fades in, everything else just completely pales in comparison - which is why it gets so dark, as a result of the simulated eye adaptation. And since the fading is so quick and follows an unusual curve, it also triggers a scene change detection somewhere in the middle. Normally, small localized changes like this shouldn't trigger a scene change, but since the brightness difference in this case is so dramatic that it drowns out the rest of the scene, it's enough to hit the threshold value...
I have the same problem with hdr-compute-peak. I get blown out brightness in just about all of my HDR movies. Most notably in Interstellar. The scenes in the ice caps and snowy plains, you can see it, but at 2:34:10, the whole picture is blown out. Below are screen caps with it enabled and disabled.
So now I keep it disabled. I'm attaching the log with hdr-compute-peak, enabled.
This might require a new issue report, but as it's so closely related I thought I'd mention it. I'm comparing HDR playback between mpv and my MiBox3 (which signals the display to use the HDR metadata). To keep as much consistency as possible, I tested using the same HDMI input which then uses all the same display settings, and used the same media. There is a noticeable difference in luminance. With the MiBox, the picture is much more vivid and bright. So I experimented with vf=format=sig-peak. That does make a notable improvement....but also causes problems. First, any value higher than 0.0, seems to have the same effect. I went as low as 0.0001 and as high as 0.9, the difference was imperceptible to me. Second, even at 0.0001, the same scene I posted from Interstellar is blown out. But the picture is improved in most other scenes (I tried several movies), both with vulkan and opengl, and hdr-compute-peak off and on. The result is the same.