Plex HTPC HDR switching won’t re-enable HDR after SDR playback when OS HDR is ON

Plex Players Desktop Players
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1

Server Version#: 4.157.0
Player Version#: v.1.71.1.346-f62ce923

Summary

When using Plex HTPC on Windows 11 with:

  • OS-level HDR enabled, and

  • Plex’s HDR switching option enabled,

Plex can successfully switch from HDR to SDR when playing SDR content, but it does not switch back to HDR afterwards. Any HDR title played after an SDR title is shown as SDR (tone-mapped) even though “HDR switching” is enabled and the media is detected as HDR.

The only way to get proper HDR output again is to manually re-enable HDR in Windows Display Settings (or restart Plex after enabling HDR again).

Environment

  • Client: Plex HTPC for Windows

  • OS: Windows 11 (fully updated)

  • GPU: NVIDIA RTX 5080

  • Display chain:

    • PC → HDMI 2.1 → Denon AVR-X6800H → HDMI 2.1 → LG G5 OLED

  • Output settings:

    • Windows display: 3840×2160 @ 120 Hz

    • Windows HDR: ON

    • Windows VRR: OFF

    • NVIDIA Control Panel:

      • Output color format: RGB

      • Output dynamic range: Full

      • Scaling: GPU

  • Plex HTPC video settings:

    • Resolution switching: Off

    • Refresh rate switching: Off

    • HDR switching: On

    • HDR metadata passthrough (experimental): On

  • Media used to test:

    • SDR: Counterpart S01E06 (1080p SDR, H.264 + TrueHD 7.1)

    • HDR: Master and Commander: The Far Side of the World (4K DoVi/HDR10, HEVC Main 10 + TrueHD 7.1)

Steps to reproduce

Starting from Windows desktop with HDR ON:

  1. Launch Plex HTPC.

  2. Confirm via LG/Denon info and Plex debug OSD that the UI is in HDR (Windows HDR is still ON).

  3. Play a HDR movie (e.g., Master and Commander 4K DoVi/HDR10).

    • Video plays in HDR correctly.

  4. Stop playback and return to the Plex HTPC dashboard.

  5. Play a SDR title (e.g., Counterpart S01E06, 1080p SDR).

    • Plex switches the output to SDR as expected; SDR looks correct.

  6. Stop playback and return to the Plex HTPC dashboard.

    • At this point, both Plex UI and Windows are now in SDR (HDR has been turned OFF at OS level by Plex).

  7. Now, from this SDR state, play the same HDR movie again (Master and Commander).

Expected result

  • When starting playback of HDR media in step 7, Plex HTPC should:

    • Re-enable HDR at the OS level (Windows HDR ON again), and

    • Output HDR to the LG/Denon (HDR10/DoVi as appropriate),

    • So the HDR movie looks the same as in step 3.

In other words, with HDR switching enabled, Plex should be able to switch:

  • HDR → SDR when playing SDR content, and then

  • SDR → HDR when playing HDR content again, even if the OS HDR state was previously ON at launch.

Actual result

  • After playing an SDR title (step 5) and returning to the Plex UI:

    • Windows HDR remains OFF, Plex UI is SDR.

  • When starting an HDR title (step 7):

    • Plex does not switch the system back to HDR.

    • The HDR title is played in SDR (HDR→SDR tone-mapped) and looks flat/washed out.

    • Windows’ Display Settings still show HDR as OFF.

  • Quitting Plex HTPC and manually re-enabling HDR in Windows restores proper HDR output for HDR titles… until another SDR title is played and the cycle repeats.

So HDR switching works one way only: HDR → SDR. It never switches back SDR → HDR if Windows HDR was ON when the client was first launched.

Additional notes / tests

  • Resolution and refresh-rate switching are both disabled specifically to avoid HDMI handshake issues with my AVR/TV chain; this bug happens with only HDR switching enabled, with resolution/refresh fixed at 4K120.

  • Manual Windows HDR toggling works fine:

    • If I manually turn HDR ON in Windows and then start Plex, HDR content plays correctly.

    • If Plex has left the OS in SDR after SDR playback, manually turning HDR back ON in Windows immediately fixes the issue for the next HDR title.

  • This strongly suggests to me that Plex HTPC is:

    • Able to turn HDR OFF at the OS level when switching to SDR, but

    • Failing to turn HDR back ON when returning to the dashboard or when HDR content is played, in the scenario where HDR was ON at app launch.

If any dev needs extra info (DXGI color space changes, more detailed logs, or a test build), I’m happy to run whatever you need. Right now, though, HDR switching from Plex HTPC on Windows 11 appears to be one-way when starting from an HDR desktop: it turns HDR off, but never restores it.

Many thanks :slight_smile:

Plex HTPC.1.log (1.2 MB)

2

Disable HDR switching in the Plex client. It’s not needed if HDR is permanently on in windows settings.

3

Thanks for the reply, @OttoKerner - unfortunately there is a clear difference with playing SDR content with HDR on vs HDR off.

SDR content with HDR on is washed out, and on pure blacks you get a sort of fuzzy white horizontal line.

I have an LG G5 TV and since HDR content looks fantastic, and SDR content with HDR off looks equally impressive, this seems to be an issue with Plex SDR > HDR tone mapping (as I understand it).

But, even if that wasn’t the case. Is it not expected user experience to have Plex switch back to previous S/HDR modes upon the file having finished playing? Not just stuck for the rest of the session in whatever mode it switched to upon initial file play?

Thanks.

4

HDR switching was designed around the output normally being in SDR and switching to HDR for HDR content, not the other way around. I don’t think switching to SDR for SDR content was ever tested nor even conceived (because that’s generally not what people want to do, especially on OLEDs).

No, that’s Windows doing the SDR → HDR tone mapping and Windows doesn’t do a great job at it.

5

Thanks, @gbooker02

Yeah, so, I watching any SDR file in HDR mode is not really viable :frowning:

All the issues would be solved if HTPC would switch back into HDR upon finishing SDR play back. Since HTPC launched in HDR would it not be trivial to have it switch back to HDR after SDR playback?

Thanks

6

@gbooker02 - if the above is not expected behaviour, is there a way I can make a feature request for HTPC to switch back to original HDR mode after SDR playback?

Thanks.