Copyright 2022 Erkki Seppälä [email protected]

Licensed under the MIT license.

midihidi

midihidi converts a MIDI keyboard to a regular evdev-supported one by reading MIDI data (via Jack or the Jack layer of PipeWire) and providing them via /dev/uinput to /dev/input/event?. This provides the ability to enter keyboard input to any Linux application, including virtual consoles.

Installing

Grab a binary built on Linux x86/64 Ubuntu from Releases, chmod +x it and move it to a directory of your choice.

You can also compile it yourself. To compile it you first need have a the Rust compiler. If your operating system doesn't come with the Rust compiler, or the compiler is too old, then the easiest way to install one is to use rustup.

Once the compiler (and cargo, the Rust package manager) is installed, you can just run the command cargo install --git https://github.com/eras/midihidi to install the latest version to ~/.cargo/bin.

Setup

You need to arrange both Jack (or PipeWire) and /dev/uinput to be accessible by the same user. The easiest and least secure way to achieve this is by changing the ownership of /dev/uinput to have the same user id as your current user id:

sudo chown $USER /dev/uinput

This change is temporary and will be reverted on boot. You can add an udev rule to make permanent changes to the permissions. Be aware that after this change any process you own is able to behave as if it were a mouse or a keyboard.

The secure alternative would be to have special user that is able to access the device via ownership or group ownership, and also able to interact with the user's media. I haven't yet tried how to make this happen..

One step easier, but still probably slightly involved due to media access permissions, would be to run midihidi as root. I would consider this secure.

Usage

For basic use you can use

midihidi --keymap alphabet

If you want it to automatically connect to some MIDI input, you can also use like

midihidi --keymap alphabet --input "Novation SL MkIII:Novation SL MkIII MIDI 1"

Once running, you can make use of the following mapping. On my keyboard with zero transposition, the lowest key of the 49-key is key 36, while the highest key is 84.

Alphabet(0) is either the key 'a' or the key 'q', on the 'alphabet' and 'qwerty' mappings, correspondingly.

        (36u8, Mapping::Alphabet(0)),
        (37u8, Mapping::Fixed(input_linux::Key::LeftCtrl)),
        (38u8, Mapping::Alphabet(1)),
        (39u8, Mapping::Fixed(input_linux::Key::LeftAlt)),
        (40u8, Mapping::Alphabet(2)),
        (41u8, Mapping::Alphabet(3)),
        (42u8, Mapping::Fixed(input_linux::Key::CapsLock)),
        (43u8, Mapping::Alphabet(4)),
        (44u8, Mapping::Fixed(input_linux::Key::Esc)),
        (45u8, Mapping::Alphabet(5)),
        (47u8, Mapping::Alphabet(6)),
    //
        (48u8, Mapping::Alphabet(7)),
        (49u8, Mapping::Fixed(input_linux::Key::Num1)),
        (50u8, Mapping::Alphabet(8)),
        (51u8, Mapping::Fixed(input_linux::Key::Num2)),
        (52u8, Mapping::Alphabet(9)),
        (53u8, Mapping::Alphabet(10)),
        (54u8, Mapping::Fixed(input_linux::Key::Num3)),
        (55u8, Mapping::Alphabet(11)),
        (56u8, Mapping::Fixed(input_linux::Key::Num4)),
        (57u8, Mapping::Alphabet(12)),
        (58u8, Mapping::Fixed(input_linux::Key::Num5)),
        (59u8, Mapping::Alphabet(13)),
    //
        (60u8, Mapping::Alphabet(14)),
        (61u8, Mapping::Fixed(input_linux::Key::Num6)),
        (62u8, Mapping::Alphabet(15)),
        (63u8, Mapping::Fixed(input_linux::Key::Num7)),
        (64u8, Mapping::Alphabet(16)),
        (65u8, Mapping::Alphabet(17)),
        (66u8, Mapping::Fixed(input_linux::Key::Num8)),
        (67u8, Mapping::Alphabet(18)),
        (68u8, Mapping::Fixed(input_linux::Key::Num9)),
        (69u8, Mapping::Alphabet(19)),
        (70u8, Mapping::Fixed(input_linux::Key::Num0)),
        (71u8, Mapping::Alphabet(20)),
    //
        (72u8, Mapping::Alphabet(21)),
        (73u8, Mapping::Fixed(input_linux::Key::Left)),
        (74u8, Mapping::Alphabet(22)),
        (75u8, Mapping::Fixed(input_linux::Key::Down)),
        (76u8, Mapping::Alphabet(23)),
        (77u8, Mapping::Alphabet(24)),
        (78u8, Mapping::Fixed(input_linux::Key::Up)),
        (79u8, Mapping::Alphabet(25)),
        (80u8, Mapping::Fixed(input_linux::Key::Right)),
    //
        (81u8, Mapping::Fixed(input_linux::Key::Backspace)),
        (82u8, Mapping::Fixed(input_linux::Key::Break)),
        (83u8, Mapping::Fixed(input_linux::Key::Space)),
        (84u8, Mapping::Fixed(input_linux::Key::Enter)),