This is a client-side web application that converts standard MIDI files (.mid, .midi) into a human-readable simple score format. The application features a built-in audio player that can play the converted or manually edited scores in real-time, supporting advanced features like live transposition, pause/resume, and progress control.

Live Demo: midi2text.pages.dev

• MIDI to Text: Converts MIDI files into a custom text-based score format (NoteNameOctave/DurationInMilliseconds).
• Two Conversion Modes:
  • Monophonic Priority: Optimizes for readability by prioritizing the main melody.
  • Polyphonic: Faithfully preserves all original tracks and concurrent notes.
• Simple Score Player: A standalone creative tool that allows you to:
  • Manually write or paste simple scores.
  • Create multiple tracks and assign different digital instruments to each.
  • Play and audition your compositions in real-time.
• Advanced Playback Controls:
  • Real-time Play/Pause and Progress Bar Seeking.
  • Live Transposition: Change the pitch of the music on the fly using a slider.
  • Track Solo/Mute: Enable or disable specific tracks during playback.
• Instrument Management:
  • Includes a variety of preset digital instruments (sine, square, triangle, sawtooth).
  • Supports adding and deleting custom instruments.
• No Backend Required: All file processing and audio synthesis happen entirely within the user's browser. No files are uploaded, ensuring user privacy.
• Responsive Design: The interface is designed to work on both desktop and mobile devices.

• Core Conversion: A WebAssembly port of the classic midicsv tool, used to parse MIDI binary files into a CSV format.
• Audio Engine:
  • Web Audio API: Used for real-time synthesis of all musical notes.
  • Web Worker: Ensures that audio playback remains precise and stable even when the browser tab is in the background, avoiding throttling of the main thread.
• Frontend Frameworks/Libraries:
  • Vanilla JavaScript (ES6+): Powers all application logic and user interactions.
  • Pico.css: Provides a lightweight, beautiful, and semantic CSS framework.
  • Plain HTML5/CSS3: Used for structuring the pages and custom styling.

midi2text/
├── css/
│   ├── pico.min.css         # Pico.css framework
│   └── style.css            # Custom application styles
├── js/
│   ├── main.js              # Main logic for the MIDI Converter page
│   ├── player_main.js       # Main logic for the Score Player page
│   ├── simple_note_player.js # Core audio player module (front-end)
│   ├── player_worker.js     # Background scheduler for the player (Web Worker)
│   ├── csv_to_simple_score.js # Logic for converting CSV to simple score format
│   ├── csvmidi.js           # JavaScript interface for the WebAssembly module
│   └── csvmidi.wasm         # The core WebAssembly conversion module
├── index.html               # The MIDI Converter page
└── player.html              # The Simple Score Player page

• The user interface, score conversion logic, and player code for this project were written for this application.
• The core MIDI-to-CSV conversion functionality is based on the metavee/midi2csv project, which is licensed under the GPL-3.0 License.
• The interface styling uses Pico.css, which is licensed under the MIT License.