Linux Jellyfin app crashes

[KisukeOboro]

Hello, I am having an issue with the Jellyfin app crashing. I am on Linux Mint using Jellyfin as a Flatpak for the player and I am hosting my own server on my Synology device as a docker container. I'm not completely sure if these issues started happening since the app update but I do know that some movies that I have been able to play before without it crashing are now crashing the program now. It's only some movies and shows and I can't find any similarities between them to figure out why these particular movies and shows are making the app crash and not others.

For some reason it is just the app that is crashing. If I switch to playing via a web browser it plays completely fine, but my Synology device isn't powerful enough for transcoding anything above 1080p, so 4K is completely unplayable for me on a web browser, which is why I'd like to get the app working correctly again so it can direct play my 4K movies and shows.

I did look at the server side logs for when the app crashes and these are the two lines that seem to be the only indication of what's going on.

[2025-03-24 05:02:11.584 +00:00] [WRN] [33] Emby.Server.Implementations.HttpServer.WebSocketConnection: WS "192.168.0.11" error receiving data: "The remote party closed the WebSocket connection without completing the close handshake."
[2025-03-24 05:02:11.737 +00:00] [INF] [33] Emby.Server.Implementations.HttpServer.WebSocketManager: WS "192.168.0.11" closed

I'm not sure where I can find the logs for the app side for Flatpak. If they are needed and someone can tell me where to find them I will provide them. Thank you so much

[TheDreadPirate]

What server version and JMP version are you running? I'm assuming JMP 1.12. Can you try right clicking anywhere in JMP and clicking "reload"? Otherwise, try clearing the JMP cache. I'm not entirely sure where that is located for the flatpak. For the deb install it is.

~/.cache/Jellyfin Media Player/
~/.local/share/jellyfinmediaplayer/

[KisukeOboro]

So I haven't done anything yet other than try to look for the folders you're indicating and I decided to do a test play again before I mess around with anything and now it isn't directly crashing, but instead now it's transcoding. And it says the reason why it's transcoding is "There was an error starting direct playback"

The server version is 10.10.6. In docker I have the tag named "latest" pulled.
The app version is 1.12.0, yeah.

I did a file search and I guess for Flatpak it has the folders you're listing under
~.var/app/com.github.iwalton3.jellyfun-media-player/cache/Jellyfin Media Player/
~.var/app/com.github.iwalton3.jellyfun-media-player/data/jellyfinmediaplayer/

So in ~/cache/Jellyfin Media Player/ there is /qmlcache and /QtWebEngine
and in /data/jellyfinmediaplayer/ there is /Codecs, /inputmaps, /logs, /scripts, /sounds, "jellyfinmediaplayer.conf", and "storage.json"
also to note in /data there is also /Jellyfin Media Player, which also has a /QtWebEngine folder
So which folders should I delete?

[TheDreadPirate]

Delete the entire folders.

~.var/app/com.github.iwalton3.jellyfun-media-player/cache/Jellyfin Media Player/
~.var/app/com.github.iwalton3.jellyfun-media-player/data/jellyfinmediaplayer/

They contain temporary data and can be safely deleted, though you will need to log in again.

[KisukeOboro]

Hmm... nope didn't work.
I also checked the same shows/movies that are crashing on the linux app and they aren't crashing on different apps (roku, android, etc) so it's just linux flatpak that's doing this from what I can see.

[TheDreadPirate]

Swap the flatpak for the debian package?

https://github.com/jellyfin/jellyfin-med...r/releases

Either Noble or Jammy, depending on which release of Mint you are on. Or Bookworm if you are on Mint DE.