CounterpointAI

A MuseScore-like web-based music notation editor with AI-powered composition assistance.

Features

• Music Notation Display: View and edit music scores using OpenSheetMusicDisplay
• File Support: Open MuseScore (.mscz), MusicXML (.musicxml, .mxl, .xml) files
• MIDI-like Playback: Listen to your compositions with Tone.js synthesis
• AI Assistant: Chat with an LLM (via OpenRouter) to modify and create music using natural language
• Score Creation: Create new scores with custom instruments, key signatures, and time signatures
• Export: Save your work as MusicXML files

Getting Started

Prerequisites

• Node.js (v14 or higher)
• npm

Installation

1. Clone the repository:

git clone https://github.com/yourusername/CounterpointAI.git
cd CounterpointAI

2. Install dependencies:

npm install

3. Start the server:

npm start

4. Open your browser and navigate to http://localhost:3000

Configuration

OpenRouter API Key

To use the AI assistant features, you'll need an OpenRouter API key:

1. Sign up at OpenRouter
2. Create an API key
3. Enter your API key in the chat panel of the application

Supported models:

• Claude 3.5 Sonnet (default)
• Claude 3 Haiku
• GPT-4o
• GPT-4o Mini
• Gemini Pro 1.5

Usage

Opening Files

• Click the folder icon or press Ctrl+O to open a file
• Supported formats: .mscz, .musicxml, .mxl, .xml

Creating a New Score

• Click the new file icon or press Ctrl+N
• Configure title, composer, key signature, time signature, and instruments
• Click "Create Score"

Editing

• Use the note palette on the left to select note durations
• Click on the score to add notes (basic editing)
• Use keyboard shortcuts:
  • 1-5: Select note duration (whole to sixteenth)
  • Arrow Up/Down: Transpose selected note
  • Delete/Backspace: Delete selected note
  • Ctrl+Z: Undo
  • Ctrl+Y or Ctrl+Shift+Z: Redo

Playback

• Click the play button or press Space to play/pause
• Adjust tempo with the BPM input
• Control volume with the slider
• Use the timeline to seek through the score
• Enable loop mode for continuous playback

AI Assistant

Chat with the AI to modify your music:

Example prompts:

• "Add a bass line to accompany the melody"
• "Transpose the score up a major third"
• "Add a countermelody in the style of Bach"
• "Fill measures 5-8 with a rhythmic variation"
• "Harmonize this melody in a classical style"

Technology Stack

• Frontend: Vanilla JavaScript, HTML5, CSS3
• Music Rendering: OpenSheetMusicDisplay (OSMD)
• Audio Synthesis: Tone.js
• File Handling: JSZip (for compressed formats)
• Backend: Express.js
• AI Integration: OpenRouter API

Project Structure

CounterpointAI/
├── public/
│   ├── css/
│   │   └── styles.css
│   ├── js/
│   │   ├── app.js
│   │   ├── score-editor.js
│   │   ├── playback-engine.js
│   │   ├── ai-assistant.js
│   │   └── musicxml-generator.js
│   └── index.html
├── uploads/
├── server.js
├── package.json
└── README.md

License

MIT License

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

• OpenSheetMusicDisplay for music notation rendering
• Tone.js for audio synthesis
• OpenRouter for LLM API access