midi-assign

midi-assign is a very simple browser-based tool for editing MIDI files to update each track's program (instrument), program banks, and channel assignments. All edits are done completely locally in the browser, so no internet connection is required and files are never uploaded anywhere. It was created specifically for the MAGFest Swadge so only instruments and program banks it supports are included, but these can be easily modified here.

Demo

A demo instance is available at dylwhich.com.

Usage

To start editing a MIDI file, either drag-and-drop the file onto the webpage, or click the Browse button to select a file. Multiple MIDI files can be selected and edited simultaneously. Each file will be displayed as a list of tracks. For each track that contains relevant MIDI events, there will be a Channel drop-down, which displays the track's current channel and can be updated to reassign that entire track to a different channel. Any tracks which already include a Program (Instrument) Change event or a Bank Select event will also include those as drop-downs. A track without any program or bank information will show a + button, which can be clicked to create those events and add their drop-downs. Note that when multiple tracks are assigned to the same channel, only one of them needs to have an instrument assigned. And also, if multiple tracks that are assigned to the same channel have conflicting instrument assignments, only one of them will actually have an effect.

Building

1. Install npm and yarn
2. Run yarn install from the project root to install NodeJS dependencies of the project
3. Run yarn run build to create the output public/bundle.js file
4. Open public/index.html in your browser