MIDI Tools

A web-based MIDI processing suite for analyzing, editing, and transforming MIDI files. Upload a MIDI file and apply various tools through an intuitive browser interface with full undo support.

Features

• File Analysis — Automatic breakdown of tracks, channels, tempo, time signature, and note/event counts
• Piano Roll — Visual note display when clicking a track
• MIDI Playback — In-browser playback with SoundFont support
• Track Editing — Change channel assignment and instrument per track
• Track Management — Delete or merge tracks
• Processing Tools:
  • Bake Tempo — Flatten tempo changes into a fixed BPM
  • Monofy — Split polyphonic tracks into separate monophonic tracks
  • Remove Redundancy — Strip duplicate control changes and redundant messages
  • Velocity Fix — Remap note velocities into a target min/max range
  • Convert to Type 0 — Merge all tracks into a single Type 0 MIDI file
• Undo History — Every operation is undoable
• Download — Export the edited MIDI file at any point

Deploying with Docker

Prerequisites

• Docker and Docker Compose

Quick Start

cd server
docker compose up -d

The application will be available at http://localhost:8000.

Build and Run Manually

cd server
docker build -t midiedit .
docker run -d -p 8000:8000 --restart unless-stopped --name midiedit midiedit

Configuration

Variable	Default	Description
Port mapping	8000:8000	Change the first port to serve on a different host port (e.g. 80:8000)

To change the port in docker-compose.yml:

services:
  midiedit:
    build: .
    ports:
      - "80:8000"
    restart: unless-stopped

Running without Docker

Prerequisites

• Python 3.10+

Setup

cd server
pip install -r requirements.txt
uvicorn app.main:app --host 0.0.0.0 --port 8000

Project Structure

server/
├── Dockerfile
├── docker-compose.yml
├── requirements.txt
└── app/
    ├── main.py                 # FastAPI application entry point
    ├── routers/
    │   └── session.py          # Session-based API endpoints
    ├── core/
    │   ├── analyze.py          # MIDI file analysis
    │   ├── track_detail.py     # Track detail + note extraction
    │   ├── baketempo.py        # Bake tempo processor
    │   ├── monofy.py           # Polyphonic-to-monophonic splitter
    │   ├── reduncheck.py       # Redundancy removal
    │   ├── velfix.py           # Velocity range remapper
    │   ├── type0.py            # Type 0 converter
    │   ├── file_handling.py    # MIDI load/save utilities
    │   └── midi_utils.py       # Shared MIDI helpers
    └── static/
        ├── index.html          # Single-page application
        ├── app.js              # Frontend logic
        └── style.css           # Styles

midi-tools/                     # Original standalone CLI scripts