MidiToMacro

This is an AutoHotKey script for Windows, to map MIDI input values to hotkeys or macros.

You can use this script to bind CC messages to media keys (play/pause/next), volume sliders, or unusual keyboard combinations (ctrl+shift+alt+F13) which you can assign in programs like StreamLabs OBS.

It's cobbled together from scripts found on the AHK forums. It originally supported mapping MIDI inputs to a virtual joystick using vJoy, and to MIDI outputs; this functionality has been removed. All credit goes to the original authors.

Running

Double click on MidiToMacro.ahk.

To launch the program when Windows starts, you can add a shortcut to the file in your Start Menu\Startup folder.

The first time you launch the script, you will be prompted to choose a MIDI input device. If you need to change it later, you can right click on the system tray icon and click MidiSet. Or, you can open the MidiMon, and change the input in the "Midi Input" dropdown menu; the script will automatically reload.

To see a log of recent MIDI input messages and any output events, right click on the system tray icon and click MidiMon. You can close this window, and the script will keep running in the background.

Adding rules

You can add rules to the file MidiRules.ahk.

There are four handler functions you can modify:

• ProcessNote: handles note on/off events
• ProcessCC: handles CC (Control Change, or Continuous Control) events
• ProcessPC: handles patch change events
• ProcessPitchBend: handle pitch bend events

Within each function, you can have a series of if/else blocks.

if (cc = 21) {
    ; ...
} else if (cc = 51) {
    ; ...
} else if (cc = 52 and value != 0) {
    ; ...
}

A rule to toggle the mute button when receiving CC 51 might look like this:

if (cc = 51) {
    Send {Volume_Mute}
    DisplayOutput("Volume", "Mute")
}

Send {Volume_Mute} simulates pressing the "mute" button on your keyboard. DisplayOutput("Volume", "Mute") logs a message to the MidiMon GUI.

A rule to press the play/pause button might look like this:

if (cc = 54 and value != 0) {
    Send {Media_Play_Pause}
    DisplayOutput("Media", "Play/Pause")
}

value != 0 lets us detect button presses, and ignores button releases, on our MIDI controller. (Without this clause, we'd send the keyboard macro twice; once for the button press, and agin for the button release.)

Here's a rule to map a continuous control from a slider to the main Windows mixer volume:

if (cc = 21 or cc = 29) {
    scaled_value := ConvertCCValueToScale(value, 0, 127)
    vol := scaled_value * 100
    SoundSet, vol
    DisplayOutput("Volume", vol)
}

ConvertCCValueToScale is a utility function from CommonFunctions.ahk. It converts a value within a give range into a floating point number between 0 and 1.

Here's a rule to trigger a keyboard shortcut in a specific application; in this example, Sound Forge 9:

if (cc = 58 and value != 0) {
    ; Place a cue marker in Sound Forge 9
    ControlSend, , {Alt down}m{Alt up}, ahk_class #32770
    DisplayOutput("Sound Forge", "Place Cue Marker")
}

You can use AutoHotKey's "WindowSpy" script to identify windows, or controls within an application, for use with ahk_class.

You can find a list of standard CC messages online. You could use any control number without a specified control function, including numbers between 20-31, 52-63, and 102-119. But, any control number should work fine.