[AppImage] MP4 video export fails / FFmpeg libraries not detected on Fedora #35528

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

Describing the bug
MP4 video export is broken in MuseScore Studio 4.7.6 AppImage on Fedora. The application fails to detect or load external FFmpeg libraries (libavcodec, libavformat, etc.) due to sandbox restrictions or version incompatibilities with recent system library updates on Fedora. Configuring ffmpegLibsDir in MuseScore4.ini or providing symbolic links to system libraries is ignored or blocked by the AppImage environment.

To Reproduce
Steps to reproduce the behavior:

1. Run MuseScore Studio 4.7.6 AppImage on Fedora.
2. Open any score and go to File > Export.
3. Select MP4 video.
4. Observe that the export option remains unavailable or requests FFmpeg despite pointing to a valid directory.

Expected behavior
MuseScore should correctly locate FFmpeg or allow proper configuration of external codecs within the AppImage environment.

Platform information

• OS: Fedora Linux
• MuseScore Version: 4.7.6.261022093 (AppImage)

Supporting files, videos and screenshots

In which versions of MuseScore Studio is this issue present?

MuseScore-Studio-4.7.6.261022093-x86_64.AppImage

Regression

I was unable to check

Operating system

Fedora 45

Additional context

MuseScore-Studio-4.7.6.261022093-x86_64.AppImage was exporting .mp4 well till last update of Fedora (45).

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible