MTS to mp4 batch file problem

[bca]

Hi
Bit new to avidemux.
Can anyone see a problem with this batch file?
It runs ok but the audio of the new file remains the same as the original file(ac3) - as though audiocodec was set to copy.
Using 2.6.7

set avidemux="C:\Program Files\Avidemux 2.6\avidemux.exe"
set videocodec=Copy
set audiocodec=Faac
set audiobitrate=384
set audioSetMixer=STEREO

for %%f in (*.MTS) do %avidemux% --video-codec %videocodec% --audio-codec %audiocodec% --audio-bitrate %audiobitrate% --audio-setmixer %audioSetMixer% --force-alt-h264 --load "%%f" --save "%%f.mp4" --quit