MIDIPlusPlus Files

Features

• Every note lands: held keys are released before they are pressed again, and notes that share a key (t and T) both play, even in one chord, and the longer one stays held.
• Low latency: a real-time playback thread with a high resolution timer, one SendInput per chord, new notes first.
• Kernel streaming MIDI input through KSMidi, with WinMM as a fallback.
• Black MIDI: 5 million notes load in about half a second and play on time.
• Game window only: switch to another app and every key is released and playback pauses. Clicking MIDI++ keeps the song going.
• Outputs: Keys (US positions, for Roblox), Typed (your keyboard layout) and MidiConnect.
• Tempo, key, velocity curves, legit mode, mute and solo per track, light and dark theme.
• Auto-transpose: finds the song's key and moves the game piano so more notes land on plain keys, while the song keeps its pitch. Turn it on with AUTO_TRANSPOSE.ENABLED in config.json.

Quick Start

1. Download the latest release, unzip it and run MIDI++.exe.
2. Put .mid files in the midi folder and pick a song.
3. Click into the game and press F1 (or press Play).

Hotkeys: F1 play/pause, F2 back 10 s, F3 forward 10 s, F4 stop and release every key. If the game runs as administrator, run MIDI++ as administrator too.

Legit Mode

Click Legit..., switch it On, set timing variation, skipped notes and random pauses, then Apply. The song reloads with the new settings and keeps its place. Live MIDI input is never changed.

Configuration

config.json sits next to MIDI++.exe. KEY_MAPPINGS accepts any US keyboard character (punctuation included), combos like ctrl+q and named keys like VK_SPACE. MIDI_SETTINGS.LIVE_WAIT_MODE can be BLOCK (default), SPIN_THEN_BLOCK or SPIN. A value that cannot be read falls back to its default and is reported in the log.

Demos

Zero latency | Remappable keys

Building

Windows 10/11, Visual Studio 2022 or newer with the C++ desktop workload. Open MIDI++.sln, pick Release x64 and build; the exe lands in x64/Release. With Visual Studio 2026 accept the retarget prompt, or build with msbuild MIDI++.sln -p:Configuration=Release -p:Platform=x64 -p:PlatformToolset=v145.

Acknowledgements

Special thanks to Gene and the MIDI++ community for invaluable feedback and support. Live input uses KSMidi (MIT).

License

GPL-3.0, see LICENSE.