The following script will convert the audio-codec on the .fmv files within the Lost Dimension/Video install directory using ffmpeg. Execute the script within the same directory as the video files.

#!/bin/bash

# Directory containing the .wmv files
directory="."

# Check if ffmpeg is installed
if ! command -v ffmpeg &> /dev/null
then
    echo "ffmpeg could not be found. Please install ffmpeg and try again."
    exit 1
fi

# Loop through all .wmv files in the specified directory
for file in "$directory"/*.wmv; do
    if [ -f "$file" ]; then
        # Get the filename without extension
        filename=$(basename "$file" .wmv)
        
        # Use ffmpeg to transcode audio to opus and keep video as is
        ffmpeg -i "$file" -c:v copy -c:a libopus "$file".mkv
        
        if [ $? -eq 0 ]; then
            echo "Successfully transcoded $file to ${filename}.wmv"
            mv $file.mkv $file
        else
            echo "Failed to transcode $file"
        fi
    fi
done