MIDI RealPlayer

Hear the MIDI you are looking at.

An open-source multi-track MIDI player and visual workspace for VS Code. It preserves note duration, velocity, tempo, program changes, and channel performance data, then plays them through real SoundFont instruments.

Building music research demos or listening tests? Use the MIDI RealPlayer npm package to embed the player in your pages.

Version 0.2.5 introduces modern artwork for all 16 General MIDI instrument families, shown on the track cards.

Modern artwork for the 16 General MIDI instrument families

You can also try the browser demo to explore the player with the updated artwork.

Features

Open a MIDI file in VS Code to listen, inspect the notes, and try a different mix. Playback follows the file's note lengths, dynamics, tempo changes, and controllers, with a SoundFont included so you can start listening right away.

Switch between a piano roll and a track overview to explore the arrangement.
Mute or solo tracks, adjust their volume, and choose different instruments.
Seek, zoom, and follow playback as you inspect a passage.
Use the bundled sounds or load your own SoundFont, then export your mix to WAV.

Your MIDI file stays unchanged; mix and instrument choices are remembered for next time.

Install

Install from the Visual Studio Marketplace, or search for MIDI RealPlayer in VS Code.

To install a GitHub release, download its .vsix, run Extensions: Install from VSIX..., and select the file.

Use

Open a .mid or .midi file.
Press Play or Space.
Seek, zoom, switch views, change a track's SoundFont preset, mute tracks, or adjust their volume directly in the viewer.

No SoundFont setup is required.

Controls

Action	Control
Play / Pause	Transport button or Space
Stop / Go to start	Transport controls
Seek	Piano roll, transport scrubber, or Left / Right
Zoom	`+`, `−`, Fit, or Ctrl/Cmd + mouse wheel
Pan	Shift + mouse wheel or horizontal trackpad gesture
Switch view	Roll / Tracks above the timeline
Vertical scale	`↕` slider above the timeline
Track preset	Sound menu beneath the track name
Track mix	M (Mute), S (Solo), and Vol slider
Follow playback	Follow control beside the transport
Export current mix	Export WAV

SoundFonts

The bundled GeneralUser GS bank provides ready-to-play General MIDI instruments. Use the SoundFont selector to switch between Default and a local .sf2, .sf3, or .dls bank.

Each track's sound label is also a preset menu. Choose another sound from the same General MIDI instrument family in the active bank, or choose MIDI to restore the file's original program. The choice is remembered per MIDI file and is applied consistently to playback, seeking, Solo, and WAV export. The bundled Concert Choir remains the default choir sound and follows the MIDI's original timing without an automatic offset.

Sound quality and preset coverage depend on the selected bank. If a requested preset is unavailable, the track displays the actual fallback sound.

Development

Requires Node.js 22 and VS Code 1.100 or newer.

git clone https://github.com/vaclisinc/midi-realplayer-vscode.git
cd midi-realplayer-vscode
npm install
npm run typecheck
npm test
npm run build

Press F5 to launch an Extension Development Host. Run npm run package to build a .vsix.

Contributing

Issues and pull requests are welcome. For playback bugs, include a minimal MIDI file when its license permits redistribution.

License and credits

MIDI RealPlayer is available under the MIT License.

Playback uses SpessaSynth and the bundled GeneralUser GS SoundFont by S. Christian Collins. The SoundFont license is included in media/GeneralUser-GS-LICENSE.txt.

Built by vaclis for musicians, researchers, and anyone tired of inaccurate MIDI previews.