Plex movie version picking behavior (https://support.plex.tv/articles/200381043-multi-version-movies/) is better but still not intelligent enough. I am making SDR versions of HDR versions by Dolby Vision tone mapping. The reason to do this is 1) to provide remote clients 20Mbps (or greater) 4K versions that don’t look weird, and 2) oddly enough in general the 4KHDR->4KSDR versions look better than similarly provided 1080p versions even on 1080p displays. Also, playing on ipads or other devices >1080p resolution, a high res SDR alternative to the HDR version is desirable. However, Plex can’t tell the difference between 4K file types. I guess it thinks “if it’s 4K it must be HDR” and will ALWAYS default to playing the 4K HDR vs 4K SDR file on any device. Some of the 4KSDR files I have are Main10 encoded and some are not. Of course all are in the BT709 space.
What Plex now needs is a bit deeper dig into the client’s playback scenario. Namely, it needs to query the client “Can you play BT2020 (or P3 too I guess) 4K HDR” and if not, it’s gotta stay away from playing that 4K HDR file. Needless to say, the playback of 4K HEVC or 4K Main10 (ie 10 bit) HEVC files encoded in the BT709 color space are transcoded with perfect colors (of course) to any client (be they 4K HDR or 1080p clients or iphones or whatever) by existing PMS infrastructure. PMS tone mapping doesn’t have a 4K problem per se. It’s a BT2020->BT709 problem where we are struggling. So for now we keep multiple versions handy.
But Plex needs to understand the different 4K versions possible, ie HDR vs SDR.
