Does mpv support native HLG output on Wayland with KDE Plasma 6.8.2?

[laichiaheng]

With KDE Plasma 6.8.2 adding support for HLG, I'm wondering how mpv currently handles HLG video output on Wayland.

When playing HLG content, does mpv convert the video to PQ (BT.2100 PQ / HDR10) before outputting it, or can it output HLG directly to the compositor?

Specifically, with vo=gpu-next and the Wayland color management protocol:

• Can mpv negotiate an HLG output colorspace with KWin and output BT.2100 HLG directly?

• If native HLG output is not currently supported, is this a limitation in mpv, libplacebo, or the Wayland color management protocol integration?

• Are there any existing options or configurations that allow HLG passthrough without converting the transfer function to PQ?

I'm particularly interested in preserving the original HLG transfer function throughout the output pipeline, rather than converting HLG content to PQ and letting the compositor handle it as HDR10.

[llyyr]

It can output pq directly if that's what the compositor wants. I don't know whether Kwin advertises HLQ or PQ or gamma2.2, mpv will output to whatever Kwin advertises by default.

You can force it to output whatever your file is via --target-colorspace-hint-mode=source, but shifts responsibility from mpv to compositor, so how well it works depends on how well the compositor implements color management