Subtitles out of sync

[Ted Hinklater]

I am also having this issue but for me the worst part is when I am watching a tv series even if I manually sync it it will desync as the episode progresses. It is very annoying.

Are the subs always a little early? I think as it's transcoding/buffering, it starts the subtitles a short time before playback on the client actually starts, and as it buffers it syncs back up.

Have you tried skipping back 10s, letting it buffer (10s+), then skipping forward 10s and resuming? Works for me if the subs are out-of-sync.

[DYNAMIC]

@Ted Hinklater
This trick doesn't work with alot of media for some reason. I have alot of media that direct playes subtitles and didn't face the problem, and can skip forward and backward no problem. Media that has this Issue (including mentioned in the post) skipping doesn't fix it.

[Pebas]

I have the same problem and I think I tried toggling every single option available on the server side in the Playback/Transcoding menu, including hardware acceleration to start with, and for instance, I even added and then removed alternative fonts.

On the client side, strange things start to happen: it replicates the problem on the TV (AndroidTV), but not on the phone (Android)... and on the PC, it also gets out of sync in Brave and Firefox (installed from scratch only for this test), but not in Chrome (?).

Note: looking at the server dashboard: in playback information, while playing in Brave and Chrome it reports that it is performing exactly the same transcodification, which is quite logical since they are very similar or even identical players since both are based on Chromium.

In all cases, the subtitles are external SRT and in some very similar movies (same audio/video codecs, etc.) it happens and in others it doesn't. You can never know in advance.

In summary:

- TV (AndroidTV), internal player: Yes
- Phone (Android), internal and web player: No
- PC Ubuntu 24.04, Brave: Yes
- Same PC, Firefox (fresh installation): Yes
- Same PC, Chrome: No

From my limited knowledge, this is becoming extremely odd.

In the last test I did, which I think could help a lot in finding a solution to the problem, is that on the phone, if I switch to the commentary audio track, the subtitle gets out of sync, and when I switch back to the main track, it adjusts again. This process can be repeated countless times with the same result, and it only happens when using the internal player; if I switch to the web player, the subtitles sync correctly with any audio track.

Then, it throws me off again: this -can't be reproduced- on ANY of the other clients.

For what is worth:
Main track codec: E-AC3 Dolby Digital Plus 5.1
Commentary track codec: AC3 Dolby Digital 2.0

EDIT: I almost forgot: In any case nothing ever changes if I skip forward or backward. Waiting or not.

--

Jellyfin Server, Web and Build: 10.9.11
GPU: NVIDiA RTX 3060 Ti LHR (NVENC)
SO for Server and Browsers: Ubuntu 24.04 (6.8.0-44-generic)
Brave: 1.69.168 Chromium: 128.0.6613.138 (Build oficial) (64 bits)
Chrome: 128.0.6613.137 (Build oficial) (64 bits)
Firefox: 130.0 (64-bit)
Phone: Android 14 and Jellyfin App 2.6.2 (using internal and web player)
TV: AndroidTV 12 and Jellyfin App 0.17.5 (using internal player)

[TheDreadPirate]

Try remuxing the video. In my testing the issue doesn't occur on the files I've encoded myself, but files from other sources sometimes have issues with SRT subtitles desyncing. Remuxing the video appears to work.

Code:

ffmpeg -fflags +genpts+igndts -i "/path/to/video.mkv" -map 0 -codec copy -max_muxing_queue_size 2048 -max_interleave_delta 0 newFile.mkv

https://forum.jellyfin.org/t-issues-with...2#pid36482

[DYNAMIC]

So the command you wrote here is for what machine ?
and also would this work if for example I used media encoder to do the job ?

Try remuxing the video.  In my testing the issue doesn't occur on the files I've encoded myself, but files from other sources sometimes have issues with SRT subtitles desyncing.  Remuxing the video appears to work.

Code:

ffmpeg -fflags +genpts+igndts -i "/path/to/video.mkv" -map 0 -codec copy -max_muxing_queue_size 2048 -max_interleave_delta 0 newFile.mkv

https://forum.jellyfin.org/t-issues-with...2#pid36482

[TheDreadPirate]

It will work with any OS with ffmpeg installed. Obviously change the path to use drive letters for Windows. In Linux, if you haven't symlinked jellyfin-ffmpeg to /usr/bin you would need to use the full path /usr/lib/jellyfin-ffmpeg/ffmpeg.