Converting MIDI to WAV and MP3 (BASH Script)

[George McGinn]

Awhile back I ran into issues where my MIDI file collection needed to be converted into an acceptable file format to be able to play it in QB64, as the only valid files are: WAV, OGG or MP3 file types.

So below is a BASH Shell script that converts a MIDI file into BOTH a .wav and a .mp3 file.

You will need to have installed:

Zenity - Used for the BASH GUI
timidity - To convert MIDI to WAV (Software synthesizer)
ffmpeg -  To convert timidity WAV to MP3 files.

Except for Zenity, timidity and ffmpeg I believe exists on all OS's, Since I only run Linux and macOS, I can't guarantee that this will run on Windows, but the principle behind what the script does should apply. I haven't completely tested it yet on my macOS, but I have installed the three requirements above. If I have any issues with it, I will post an update (not an edit). I know not all features of Zenity work on a macOS system. So I may create a command-line version.

Now I can convert all my Christmas MIDI files into WAV and MP3 files.

Merry Christmas.

Code: Bash: [Select]

1. #!/bin/bash
2. #
3. # MIDI to WAV and MP3 Converter -- Shell Script -- George McGinn 2021
4. #Version 1.0 -- December 19, 2021
5. #
6. # convertMIDI - Script to convert a MIDI file into both a .WAV and .MP3
7. #               audio formats. Uses Zenity to retrieve the MIDI file,
8. #               create the output files, show progress, and other messages.
9. #
10. # NOTES: This script needs the following installed:
11. #        Zenity - Script's GUI
12. #        timidity - Converts the MIDI to a WAV format
13. #        ffmpeg - Converts a MIDI/WAV to MP3 format
14. #
15. # USEAGE:
16. #   This script can be invoked from a File Manager or from a terminal
17. #   session. When started, it defaults to your $HOME/Music directory.
18. #   Select the location of your MIDI file. You will be able to change
19. #   the directory. Select your MID or MIDI file then click [OK]. Next
20. #   The output for the WAV and MP3 files will default to your $HOME/Music
21. #   directory. You can change this location. Enter the file name WITHOUT
22. #   any extensions. The .wav and .mp3 will be added to the file name
23. #   you provide. The script will create both files.
24. #
25. #   If you select directory(ies) that require ROOT access, the script will
26. #   ask you for your password and then do the conversions as stated above.
27. #   There is no need to start this script with sudo.
28. #
29.  
30. # Change directory to Home/Music
31.  
32. cd $HOME/Music
33.  
34. # Get the MIDI path/file name
35. mid=$(zenity --file-selection)
36. if [ $? = 1 ];
37.         then exit
38. fi
39.  
40.  
41. # Get save path/file name
42. wav=$(zenity --file-selection --save --confirm-overwrite)
43. if [ $? = 1 ];
44.         then exit
45. fi
46.  
47. # see if current user has write permissions by creating an empty file
48. > "$wav:".wav
49. > "$wav".mp3
50.  
51. # if so, delete the empty files and do the conversion and show progress bar
52. if [ $?  -eq 0 ]; then
53.         rm "$wav:".wav
54.         rm "$wav".mp3
55.  
56.         timidity "$mid" -Ow -o "$wav".wav  | zenity --progress --pulsate --auto-close --text "Converting to WAV..."
57.         timidity "$mid" -Ow -o - | ffmpeg -i - -acodec libmp3lame -ab 64k "$wav".mp3 | zenity --progress --pulsate --auto-close --text "Converting to MP3..."
58.  
59. # Tell us the conversion is done
60.         zenity --info --text "Conversion complete!"
61.  
62. # if not, get root password, run command as root
63. else
64. # Get the users password
65.         passwd=$(zenity --password)
66.  
67. # Do the conversion and show a progress bar
68.         echo $passwd|sudo -S timidity "$mid" -Ow -o "$wav".wav | zenity --progress --pulsate --auto-close --text "Converting to WAV..."
69.         echo $passwd|sudo -S timidity "$mid" -Ow -o - | ffmpeg -i - -acodec libmp3lame -ab 64k "$wav".mp3 | zenity --progress --pulsate --auto-close --text "Converting to MP3..."
70.  
71.         if [ $? = 1 ];
72.                 then exit
73.         fi
74.  
75. # Tell us the conversion is done
76.         zenity --info --text "Conversion complete!"
77. fi
78.  

[johnno56]

George,

Many thanks for the script. I have a squillion (not actually a squillion but lots...) midi files that cound make use of this script. Thank you. Your blood's worth bottling.

J

ps: Just tested the script and ran like a charm!!

Sample output:
 

insideout.mid

 

inside.mp3

(the 'wav' file is 30mb! - too large to attach)