Transcoding always removes HDR, even if the client supports HDR?

[randompersonx]

Hello,

I've recently started using Jellyfin, and set up version 10.9.3.

Overall, it has a lot of very nice functionality compared to Plex - in my experience, Jellyfin handles subtitles better, and also transcoding, thanks to hardware accelerated HEVC, also performs better than Plex (which can only do H.264).

With that said, I've found that no matter what I do, when transcoding 4K HDR content (to a lower 4K bitrate, or to 1080p, etc), it will drop down to rec720 8-bit. If I leave tonemapping enabled (either VPP or regular), it does handle this well enough that the video is watchable, but I'd of course prefer to watch the content in HDR.

I'm using an intel i9-14900k on a Linux 6.5 kernel, and all the hardware acceleration seems to work just fine.

Does anyone have any suggestion on how to keep it in HDR if the client supports?

I've tested playback on M3 Macbook Pro, iPhone 15 Pro, and a LG G2 OLED.

Thanks in advance!

[bitmap]

There is no HDR --> HDR transcoding. If the media requires video transcoding for any reason, it is transcoded + tonemapped to SDR. This is true even if transcoding needs to happen because the client doesn't support, say....PGS subs.