transcriber/transcribe.py

#!/usr/bin/env python3
"""Transcribe an audio file to MIDI using basic-pitch."""

import sys
from pathlib import Path

# Patch scipy.signal.gaussian (removed in scipy >=1.12, basic-pitch hasn't updated)
import scipy.signal
if not hasattr(scipy.signal, "gaussian"):
    from scipy.signal.windows import gaussian
    scipy.signal.gaussian = gaussian

from basic_pitch.inference import predict
import basic_pitch
_MODELS_DIR = Path(basic_pitch.__file__).parent / "saved_models" / "icassp_2022"
ONNX_MODEL_PATH = _MODELS_DIR / "nmp.onnx"

def transcribe(input_path: str, output_path: str | None = None):
    input_file = Path(input_path)
    if not input_file.exists():
        print(f"Error: {input_file} not found")
        sys.exit(1)

    if output_path is None:
        output_path = input_file.with_suffix(".mid")
    else:
        output_path = Path(output_path)

    print(f"Transcribing {input_file}...")
    model_output, midi_data, note_events = predict(
        str(input_file),
        ONNX_MODEL_PATH,
        onset_threshold=0.33,
        frame_threshold=0.20,
        minimum_note_length=100.0,
    )

    midi_data.write(str(output_path))
    print(f"MIDI written to {output_path}")
    print(f"Found {len(note_events)} note events")
    return output_path

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python transcribe.py <audio_file> [output.mid]")
        sys.exit(1)

    input_file = sys.argv[1]
    output_file = sys.argv[2] if len(sys.argv) > 2 else None
    transcribe(input_file, output_file)