waveにsmplつけるやつ

smpl.py

import os
import struct
import sys
import wave


def set_loop(input_path, output_path, start_time=None, end_time=None):
    with open(input_path, 'rb') as f:
        wave_data = f.read()

    sample_rate = None
    for i in range(len(wave_data) - 4):
        if wave_data[i:i+4] == b'fmt ':
            sample_rate = struct.unpack('<I', wave_data[i+12:i+16])[0]
            break
    if sample_rate is None:
        return

    with wave.open(input_path, 'rb') as wav_file:
        total_frames = wav_file.getnframes()

    if start_time is None:
        start_time = 0.0
    if end_time is None:
        end_time = total_frames / sample_rate

    start = int(sample_rate * start_time)
    end = int(sample_rate * end_time)

    smpl_index = None
    for i in range(len(wave_data) - 4):
        if wave_data[i:i+4] == b'smpl':
            smpl_index = i
            smpl_chunk_size = struct.unpack('<I', wave_data[i+4:i+8])[0] + 8
            wave_data = wave_data[:i] + wave_data[i + smpl_chunk_size:]
            break

    smpl_chunk = bytearray(68)
    smpl_chunk[0:4] = b'smpl'
    struct.pack_into('<I', smpl_chunk, 4, 60)
    struct.pack_into('<I', smpl_chunk, 20, 60)
    struct.pack_into('<I', smpl_chunk, 36, 1)
    struct.pack_into('<I', smpl_chunk, 52, start)
    struct.pack_into('<I', smpl_chunk, 56, end)

    wave_data += smpl_chunk

    riff_index = wave_data.find(b'RIFF')
    if riff_index == -1:
        return
    file_size = len(wave_data) - 8
    wave_data = wave_data[:riff_index + 4] + \
        struct.pack('<I', file_size) + wave_data[riff_index + 8:]

    with open(output_path, 'wb') as f:
        f.write(wave_data)


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Usage: python script.py <input_path> [start_time] [end_time]")
        sys.exit(1)

    input_path = sys.argv[1]
    output_path = f"{os.path.splitext(input_path)[0]}_smpl.wav"
    start_time = float(sys.argv[2]) if len(sys.argv) > 2 else None
    end_time = float(sys.argv[3]) if len(sys.argv) > 3 else None

    set_loop(input_path, output_path, start_time, end_time)