bpm.py

#!/usr/bin/env python3
import os
import sys
import warnings
import numpy as np
import librosa
from mutagen.easyid3 import EasyID3

# Suppress librosa UserWarnings and FutureWarnings
warnings.filterwarnings("ignore", category=UserWarning)
warnings.filterwarnings("ignore", category=FutureWarning)

def detect_bpm(file_path):
    """Detect BPM of an audio file using librosa."""
    try:
        y, sr = librosa.load(file_path, sr=None)
    except Exception as e:
        print(f"[ERROR] Failed to load '{file_path}': {e}")
        return None

    if y is None or y.size == 0:
        print(f"[SKIP] '{file_path}' contains no audio data.")
        return None

    try:
        tempo, _ = librosa.beat.beat_track(y=y, sr=sr)
        # Handle cases where tempo is returned as an array
        if isinstance(tempo, np.ndarray):
            tempo = float(tempo[0]) if tempo.size > 0 else None

        if tempo is None or tempo <= 0:
            print(f"[SKIP] Could not detect BPM for '{file_path}'")
            return None

        bpm = int(np.round(tempo))
        return bpm
    except Exception as e:
        print(f"[ERROR] BPM detection failed for '{file_path}': {e}")
        return None

def write_bpm_to_id3(file_path, bpm):
    """Write BPM to the ID3 tags of an MP3 file."""
    try:
        audio = EasyID3(file_path)
    except Exception:
        # Create new ID3 tags if none exist
        from mutagen.id3 import ID3
        audio = ID3()
        audio.save(file_path)
        audio = EasyID3(file_path)

    try:
        audio['bpm'] = str(bpm)
        audio.save()
        print(f"[OK] BPM {bpm} written to '{file_path}'")
    except Exception as e:
        print(f"[ERROR] Failed to write BPM to '{file_path}': {e}")

def process_file(file_path):
    """Process a single MP3 file."""
    if not file_path.lower().endswith('.mp3'):
        print(f"[SKIP] Not an MP3 file: '{file_path}'")
        return

    bpm = detect_bpm(file_path)
    if bpm is not None:
        write_bpm_to_id3(file_path, bpm)

def process_folder(folder_path):
    """Recursively process all MP3 files in a folder."""
    for root, _, files in os.walk(folder_path):
        for file in files:
            file_path = os.path.join(root, file)
            process_file(file_path)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python bpm_tag.py <file_or_folder>")
        sys.exit(1)

    target = sys.argv[1]

    if os.path.isfile(target):
        process_file(target)
    elif os.path.isdir(target):
        process_folder(target)
    else:
        print(f"[ERROR] '{target}' is not a valid file or folder")
        sys.exit(1)