LG G4 transcoding (DoVi, DTS, TrueHD)

[sonyci]

https://github.com/jellyfin/jellyfin-web/issues/6484

Cross-posting here, in case someone has an idea.

Using the webos jellyfin player which is a thin wrapper around jellyfin-web.
Bug 1: DoVi 8.1 file triggers transcoding on LG G4.
Bug 2: Disabling transcoding for this user allows playing this file DV content just fine with direct stream, but the two audio tracks which are DTS HDMA and Dolby TrueHD with Atmos get transcoded to AAC (DTS and TrueHD passthrough options are checked in the settings)

I have the fMP4 checkbox unchecked. The passthrough for DTS and TrueHD is set to true in the jellyfin webos app options. My setup is capable of both TrueHD and DTS. LG is plugged to my AVR with eARC.
In the log file, I can see the transcoding happening to aac (-codec:a:0 libfdk_aac):

I have the fMP4 checkbox unchecked. The passthrough for DTS and TrueHD is set to true in the jellyfin webos app options. My setup is capable of both TrueHD and DTS. LG is plugged to my AVR with eARC.
In the log file, I can see the transcoding happening to aac (-codec:a:0 libfdk_aac):

Code:

User policy for "xxx". EnablePlaybackRemuxing: True EnableVideoPlaybackTranscoding: False EnableAudioPlaybackTranscoding: True

[2025-01-27 00:22:34.592 +01:00] [INF] [24] MediaBrowser.MediaEncoding.Transcoding.TranscodeManager: "/usr/lib/jellyfin-ffmpeg/ffmpeg" "-analyzeduration 200M -probesize 1G -fflags +genpts -f matroska -i file:"/data/media/movies/xxx.mkv" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:4 -map -0:s -codec:v:0 copy -tag:v:0 dvh1 -strict -2 -bsf:v hevc_mp4toannexb -start_at_zero -codec:a:0 libfdk_aac -ac 6 -ab 640000 -copyts -avoid_negative_ts disabled -max_muxing_queue_size 2048 -f hls -max_delay 5000000 -hls_time 6 -hls_segment_type mpegts -start_number 0 -hls_segment_filename "/config/cache/transcodes/a5f2f1e0be1aa7fa930b492158e5938e%d.ts" -hls_playlist_type vod -hls_list_size 0 -y "/config/cache/transcodes/a5f2f1e0be1aa7fa930b492158e5938e.m3u8""

[bitmap]

Can you provide more info on the media as well as the snippet that includes transcode reason from the logs or the dashboard during playback?

I know LGs suffer(ed) from not being able to play DV in MKV files. I'll test with a DV MKV when I get back home on my C1. I'll also take a look at settings to see if there are any that can better provide passthrough, although I don't have a receiver to test with unfortunately.

[DaveR1974]

This is not a Jellyfin issue. Newer LG TVs are incompatible with MKVs that are Dolby Vision. The only solution at present is to change the MKV file to MP4 before placing it on the server. See this thread showing testing and a walkthrough for conversion.