Avidemux batch convert with "Muxer cannot open" error

[sansonet]

I have over 200 videos where I need to change sound only, from ACC to AC3. Those are scripts I'm using, but getting an error "Muxer cannot open"

#!/bin/bash
for FIL in `ls *m4v | sort` ; do
  /mnt/home/appimages/avidemux_2.8.0.appImage --force-alt-h264 --load "$FIL" --run ac3.py --save ${FIL%.*}.mp4 --quit
done

ac3.py script:

#PY  <- Needed to identify #
#--automatically built--

adm = Avidemux()
adm.videoCodec("Copy")
adm.audioClearTracks()
adm.audioAddTrack(0)
adm.audioCodec(0, "LavAC3")
adm.audioSetDrc(0, 0)
adm.audioSetShift(0, 0, 0)
adm.setContainer("MP4")

When doing it in windows, all works fine with this bat script and the same "py" file, but I don't like to log in windows every time I need to convert

 set avidemux="C:\Program Files\Avidemux 2.7 VC++ 64bits\avidemux.exe"
for %%f in (*.m4v) do %avidemux% --load "%%f" --run "ac3.py" --save "%%f.mp4" --quit

Does anybody know what is wrong with scripts and how I can fix it?

[ProWo]

In windows code there exist a variable avidemux, missing in the first code.