MMCH comverter to MP4

mmch.sh

#!/bin/bash                                                                                                                                                                                          
                                                                                                                                                                                                     
D="output"                                                                                                                                                                                           
mkdir -p "$D"                                                                                                                                                                                        
                                                                                                                                                                                                     
if [ ! "$1" ]                                                                                                                                                                                        
then                                                                                                                                                                                                 
  echo "Usage: $0 <file>"                                                                                                                                                                            
  exit 1                                                                                                                                                                                             
fi                                                                                                                                                                                                   
I="$1"                                                                                                                                                                                               
B="${I##*/}"                                                                                                                                                                                         
N="${B%.*}"                                                                                                                                                                                          
X="${B##*.}"                                                                                                                                                                                         
A="$D/$N.wav"                                                                                                                                                                                        
T="$D/$N.$X"                                                                                                                                                                                         
O="$D/$N.mp4"                                                                                                                                                                                        
                                                                                                                                                                                                     
# Extract audio                                                                                                                                                                                      
ffmpeg -i "$I" "$A"                                                                                                                                                                                  
# Normalize audio                                                                                                                                                                                    
normalize-audio "$A"                                                                                                                                                                                 
# Create temporary video                                                                                                                                                                             
ffmpeg -i "$I" -i "$A" -acodec copy -vcodec copy "$T"                                                                                                                                                
# Encode the output video                                                                                                                                                                            
HandBrakeCLI -e x264 -S 175 -2 -E faac -B 160 -X 640 -5 -i "$T" -o "$O"                                                                                                                              
# Remove temporary files                                                                                                                                                                             
rm "$A" "$T"