Well, after trying different solutions for 13 hours finally I’ve managed to get the App Work again perfectly just like it should
Turns out as my application is using Gstreamer which uses Gnome’s GVFS which an virtual filesystem by Gnome which is designed to work with the I/O abstraction of GIO, it needs access to that. Since gvfs is a virtual filesystem I need permissions to access it from my application
This stupid line has cost me 13 hours🤦
- --filesystem=xdg-run/gvfs
Summary, your app needs permissions to play Audio from Gstreamer when being used inside Flatpak. Just append --filesystem=xdg-run/gvfs to finish-args of your manifest
BTW, if your app uses Dbus MPRIS than you’ve to also use --own-name=org.mpris.MediaPlayer2.<you-app-name> in the finish-args