Problem Dolby Vision after update

[Sergi Sans Roselló]

Hello,

After updating my Jellyfin server from version 10.10.7 to 10.11, Dolby Vision playback stopped working on my LG C1 OLED (WebOS app).

Before the update, the same exact file correctly triggered Dolby Vision on the TV (the DV logo appeared and playback worked perfectly).
Now, with server 10.11, the same file only plays as HDR10, and the Dolby Vision flag no longer activates.

No other components have changed:
The WebOS client app is the same version as before.
The TV firmware hasn’t been updated.
Server configuration (playback, transcoding, remux options, etc.) is identical.

Thanks,

[Sergi Sans Roselló]

Hi everyone,
I’ve been investigating why Dolby Vision (Profile 8.1) playback stopped working on my LG C1 (native WebOS app) after updating my Jellyfin server from version 10.10.7 to 10.11.

I ran tests with the exact same video file and compared server logs between both versions, and these are my conclusions.

Technical analysis
In Jellyfin 10.10.7, the video stream is handled as Direct Stream / Direct Play, keeping the HEVC video bitstream untouched:

-codecv copy
-codeca copy
-tag:v dvh1
-bsf:v hevc_mp4toannexb

This preserves the Dolby Vision RPU metadata in the HEVC stream (Profile 8.1 + HDR10 compatibility), and the LG C1 correctly recognizes and activates Dolby Vision mode.

However, in Jellyfin 10.11, there’s a subtle change in the ffmpeg command that breaks playback:
-codecv copy
-tag:v dvh1
-bsf:v hevc_mp4toannexb
-codeca libfdk_aac -ac 6 -ab 640000

That means the audio stream gets transcoded to AAC (libfdk_aac) instead of being copied.
This forces Jellyfin to re-mux the video and audio into a new HLS container, which ends up stripping or invalidating the Dolby Vision metadata.
As a result, LG TVs no longer detect the DV layer and only display HDR10 fallback.

I also noticed that in 10.11 the FFmpeg build has been updated to 7.1.2-Jellyfin, and it uses a compression 0 DOVI header format, which might worsen compatibility with some clients that require an intact bitstream.

Could someone from the development team please review this behavior change?
It seems that Dolby Vision Profile 8.1 streams can no longer be passed through natively when Jellyfin 10.11 decides to transcode audio.
It would be helpful if the new ffmpeg handling could preserve DV compatibility when only audio transcoding occurs, or allow overriding it via a setting.

I can share both log files (10.10.7 working and 10.11 failing) for reference if needed.

Thanks,

[draxer]

Please go into Playback settings on your TV in Jellyfin, check the box for Prefer fMP4-HLS Media Container. On top of that you could also check the new setting to prefer shorter HLS segments it claims to improve performance for LG TVs. This fixed this issue in my case.

[Sergi Sans Roselló]

Thank you so much — that worked perfectly!
I checked “Prefer fMP4-HLS Media Container” and also the new option for shorter HLS segments, and Dolby Vision is now working correctly again on my LG C1.
Really appreciate your help!

[draxer]

np np!