HDR to HDR Transcoding

Feature Suggestions
1

It’s 2023! There are so few SDR devices on the market anymore, and almost no SDR content being produced these days. While most of my 4K files are too big to stream without transcoding, it sucks that Plex tone-maps HDR to SDR without an option to just keep the same color space as the source. Especially because most Plex clients are aware of the capabilities of the attached display, it shouldn’t be impossible to only tone-map when strictly necessary (like streaming to your grandma’s TV).

2

I think this is a reasonable request but HDR is not ubiquitous. I am not your grandmother, I love gadgets, and yet none of my ~10 screens are HDR capable. I’ve never even seen HDR or 4k programming outside of a store display. And it will be a few more years before that changes.

3

I guess my thinking is pretty US-centric. But in the US everything has been HDR for a couple years now.

4

I’m also in the USA. Sure, new programming and hardware is all HDR but when a TV lasts so long … There’s plenty of SDR hardware still around, too. I don’t have HDR simply because I haven’t needed to buy a screen in a long, long time.

My phone is also 4 years old and my car is 23. :person_shrugging:

6

Well it’s 2026 now, hdr is still premium but with the rise of oled and the constant release of new gpus I think it’s time to reignite this conversation.

7

What exactly are you asking for?

HDR to HDR transcoding should work when encoding to HEVC (this support article is a bit outdated as it’s no longer “experimental”: https://support.plex.tv/articles/transcoder/);

Settings → Transcoder

image

11

The only way I have found to watch hdr content is with direct play. When transcoding the image on certain media files ( i believe it has something to do with dolby and meta data ) the picture is dull and not nearly as bright. I understand plex has implemented tone mapping algorithms, but it’s really only a mask for the problem. When i bring this problem up I don’t mean it to sound like the solution is simple.

12

I suppose drzoidberg33’s question remains…
Have you configured your server to enable HEVC video encoding (and does your server run on a platform with support for said HEVC hw-accelerated transcoding – e.g. using a modern iGPU or supported dedicated GPU)?

13

Yes hevc is enabled. My current setup will handle encoding and decoding at 4k without lag. I just don’t get the hdr or dolby logos when transcoding/decoding. I can’t say I’m a master a tuning but I have played with the settings. ( edit: and the picture will be dim without proper contrast)

14

Plex cannot transcode Dolby Vision. Period. They are not licensed for it and will not skirt that requirement.

15

That’s interesting, it’s easy to forget everything is licensed these days.

16

Need more information on what format the content is and what device you’re playing back on.

17

Hi Drzoidberg, thanks for the reply. "This is an AI template i have modified "

To answer your questions, here are the specifics of my setup and the file formats I am using:

1. Content Format:

  • Container: MKV / MP4

  • Video Codec: HEVC (H.265) 10-bit

  • HDR Standard: Primarily HDR10+ and Dolby Vision (Profile 5/8).

  • Audio: TrueHD Atmos / DTS-X (Passthrough to AVR).

  • Transcoding Setting: I am forcing a transcoded stream where the client is not capable of direct play (e.g., playing through a specific renderer that requires conversion, or a specific mobile client).

  • Result: When forced to transcode, the HDR/10-bit flags are lost. The image appears washed out, lacks peak brightness, and the DV/HDR logos in the player overlay often vanish.

2. Client Device:

  • Device: [HISENSE_55U65QF]

  • OS/Software Version: [Fire os 8.1.7.1]

  • Display Capabilities: The display supports HDR10 and Dolby Vision.

3. Server Configuration:

  • Hardware: [Dual socket e5-2697aV1,5060ti]

  • Acceleration: Hardware Transcoding (QuickSync/Media Engine) is enabled.

  • Plex Settings: HEVC encoding is toggled On. Tone Mapping is currently set to [Clip].

The Specific Issue: As mentioned in my previous post, the issue isn’t just brightness; it is the color space retention. When the video is re-encoded by the server, the HDR metadata (the PQ curve or DV profiles) often gets stripped or converted to SDR with tone mapping. This results in a “flat” image that doesn’t utilize the display’s full dynamic range, even though my device is fully HDR-capable.

The Question: Given that pshanew mentioned Dolby Vision licensing limitations for transcoding:

  1. Is it possible to configure Plex to transcode the video stream but retain the HDR metadata passthrough? (e.g., Re-encode the video bitrate, but keep the HDR signal).

  2. Or, is the expectation currently that if a transcode occurs, the server should assume the client handles the tone mapping (SDR)?

  3. If the server re-encodes to HDR10, can we ensure the tone mapping isn’t applied automatically on the server side, allowing the display to handle the conversion?