services/midi_converter.py

from basic_pitch.inference import predict_and_save
from basic_pitch import ICASSP_2022_MODEL_PATH
import os

class MidiConverter:
    def __init__(self):
        print("Initializing Basic Pitch for MIDI conversion...")
        self.output_dir = "midi_output" 

    def convert(self, audio_path: str, output_path: str):
        """
        Convert audio file to MIDI using Basic Pitch.
        """
        try:
            # basic-pitch handles loading internally
            # It saves multiple files (mid, csv, npz), we only care about mid
            
            # output_path should be a directory or file? 
            # predict_and_save takes output_directory
            
            output_dir = os.path.dirname(output_path)
            file_name_no_ext = os.path.splitext(os.path.basename(output_path))[0]
            
            print(f"Converting {audio_path} to MIDI...")
            
            # Tuned parameters for better accuracy
            predict_and_save(
                [audio_path],
                output_dir,
                True, 
                False, 
                False, 
                False, 
                ICASSP_2022_MODEL_PATH,
                onset_threshold=0.6,    # Higher threshold to reduce noise
                frame_threshold=0.4,
                minimum_note_length=100.0, # ms
                minimum_frequency=None,
                maximum_frequency=None
            )
            
            # Basic Pitch saves as <original_name>_basic_pitch.mid
            # We need to rename it to expected output_path if needed
            original_basename = os.path.splitext(os.path.basename(audio_path))[0]
            generated_midi = os.path.join(output_dir, f"{original_basename}_basic_pitch.mid")
            
            if os.path.exists(generated_midi):
                if os.path.exists(output_path):
                    os.remove(output_path)
                os.rename(generated_midi, output_path)
                print(f"MIDI saved to {output_path}")
                return output_path
            else:
                print("Warning: Expected MIDI file not found.")
                return None
                
        except Exception as e:
            print(f"Error converting to MIDI: {e}")
            import traceback
            traceback.print_exc()
            return None