Convert/Save and Multiple Files

[Budgie]

Running version 3.0.0-git Vetinari on openSUSE Leap 42.2 with KDE Desktop.

I am trying to extract the audio as flac from a series of .m4v files created by HandBrake from a DVD. This works well for a single file but not for multiple files.

My main problem is that if I select multiple files by adding them to the Convert/Save File selection only the first and sometimes the second file is processed and then VLC crashes and closes.

The files are created using chapter markers and I hoped to be able to obtain a series of flac files which would when played be the equivalent of those ripped from an audio CD.

I could convert one at a time but there are 43 files from only one DVD and I have several DVDs to do.

Just out of interest I tried to enter several sequential files using Open Multiple Files in order to play the videos but this failed too.

What am I doing wrong please?