Ok, when a 4k bluray is ripped, it becomes a single layer video.
That is why when you try to play an HDR video on an SDR tv, the colors are washed out, because (currently) plex doesn’t do any color conversion or remapping and the tv doesn’t understand HDR.
as far as I am aware, there are no hdr10+ rips yet, so for now we only have regular hdr rips.
DV rips, as mentioned previously are limited to lossy audio only.
so when direct playing 4k/hdr, plex is not combining or decoding or encoding the video, the device itself can read the provided HDR video and boom we have hdr video.
When transcoding, plex takes that native x265 10bit video stream and converts to x264 (which is what we have been using for years). Plex currently does not do any color mapping/conversion while transcoding, so again the colors get washed out.
Plex uses the open source FFMPEG program, which I guess that plex adds their own ‘magic sauce’ to customize it for real time conversion/streaming, so it is going to be limited by whatever capabilities that ffmpeg provides natively, along with any tweaks plex team does.
so plex doesn’t change the video stream when direct playing, and when it converts/transcodes, the codec is changed (265 to 264), and hdr is lost.
as far as DV, plex does not/has not licensed the necessary technology to decode/convert it.
DV played directly, will work with compatible displays.
the problem with dv played directly, goes back to what I said above, there are multiple types of DV, and different versions/levels, and not all DV devices can play back all types of DV.
DV is a mess, and there is no easy solution.
Hopefully, HDR10+ will becomes the new standard and make DV irrelevant.
Even then, it will no doubt take even more years for HDR10+ to mature (content, displays, and software wise) and become as ‘simple’ as HDR is. (of which neither x265 or HDR are not simple anyway)
If you have not already seen it, there is a whole thread @ Plex, 4k, transcoding, and you - aka the rules of 4k - a FAQ - General / General Discussions - Plex Forum that might be of interest.
as far as DV rips, the only reason they exist at all is because there is an obscure dolby vision software decoder that can take 4k bluray dv streams and decode/remux them into a single video stream (similar to streaming DV), unfortunately it only supports mp4 and lossy audio. and only certain tvs support that
at least since last time I saw any news about it.
