A Beginner’s Guide to the Audio-to-MIDI Converter

Music technology has come a long way, and one of the most exciting advancements is the ability to convert audio files into MIDI data. MIDI (Musical Instrument Digital Interface) is a format that captures musical information like pitch, velocity, and timing, which can then be edited, analyzed, or played back using software or digital instruments.

Today, we’ll dive into a tool that simplifies this process: ComfyUI Basic Pitch, a Python-based solution. We’ll explore its components and functionality step-by-step.

What Does This Tool Do?

This tool includes two key nodes:

1. AudioToMidi: Converts audio files (like recordings of instruments or singing) into MIDI data.
2. SaveMidi: Saves the processed MIDI data into a file you can use in music software or share with others.

Let’s break down how these nodes work and what makes them beginner-friendly.

Node 1: AudioToMidi

This is where the magic happens. The AudioToMidi node uses a machine learning library called Basic Pitch to analyze audio files and convert them into MIDI data.

How It Works

1. Inputs:
   • Audio Path: Path to the audio file you want to convert.
   • Onset Threshold: (Optional) Controls how sensitive the system is to detecting when a note starts.
   • Frame Threshold: (Optional) Adjusts how sensitive the system is to maintaining notes over time.
2. Processing:
   • The tool uses the predict function from the Basic Pitch library to:
     • Detect notes (onset).
     • Track the duration and intensity of each note.
   • The resulting data includes the pitch, start time, end time, and velocity (how hard the note was played).
3. Output:
   • A list of notes in MIDI format, sorted by their start time.

Example Output

Here’s what a single note might look like in the processed MIDI data:

scssCopy code(60, 0.5, 1.5, 100)

• 60: Pitch (middle C).
• 0.5: Start time in seconds.
• 1.5: End time in seconds.
• 100: Velocity (how hard the note was played).

Node 2: SaveMidi

Once you’ve converted your audio into MIDI data, this node helps you save the results as a .mid file that you can use in music software like GarageBand, Ableton, or FL Studio.

How It Works

1. Inputs:
   • MIDI Data: The output from the AudioToMidi node.
   • File Name: Name for the output file (e.g., my_song.mid).
   • Output Path: Directory where the file will be saved.
   • Tempo: The speed of the song in beats per minute (BPM).
2. Processing:
   • Uses the midiutil library to create a MIDI file.
   • Loops through each note in the MIDI data, ensuring the values (like pitch and velocity) stay within valid MIDI ranges.
3. Output:
   • A .mid file stored at your chosen location.

Why Is This Useful?

• You can edit the MIDI file in any digital audio workstation (DAW).
• Share your music with collaborators or use it in performances.

Comparison Table: Inputs and Outputs of Each Node

Example Workflow

1. Step 1: Prepare your audio file.
   • Ensure it’s a clean recording of a single instrument or voice for the best results.
2. Step 2: Use the AudioToMidi node.
   • Provide the path to your audio file and adjust sensitivity thresholds if needed.
3. Step 3: Review the MIDI output.
   • Check the note data for accuracy (e.g., pitch, timing).
4. Step 4: Use the SaveMidi node.
   • Choose a file name, tempo, and save location for your MIDI file.
5. Step 5: Open the file in your DAW.
   • Edit the MIDI data, add effects, or layer with other instruments.

Beginner-Friendly Features

• Adjustable Thresholds: Fine-tune how sensitive the conversion is, ensuring accurate note detection.
• Error Handling: Clear messages if something goes wrong, like a missing file.
• Ease of Use: Simple inputs and outputs make this tool accessible, even if you’re new to MIDI or coding.

Conclusion

The ComfyUI Basic Pitch nodes are a powerful yet approachable way to convert audio into MIDI. Whether you’re a musician, producer, or hobbyist, this tool can open new creative possibilities. By converting raw recordings into editable MIDI data, you can easily refine and remix your music, making it more versatile than ever.

If you’re excited to try this, download the repository, install the necessary Python libraries, and start transforming your audio files into musical masterpieces!