wave file lsb and msb histogram

analysis.py

import wave

FILENAME = 'Eternal Snow_이용신_Returned Fullmoon.wav'

wav = wave.open(FILENAME, mode='rb')

n_channels, sample_width, frame_rate, no_frames, _, _ = wav.getparams()
sample_bits = sample_width * 8

print(f'{FILENAME}')
print(f'{n_channels} channels, {frame_rate} kHz, {sample_bits} bits')
print(f'{no_frames / frame_rate:.3f} seconds long')

hist_left = [0] * (2**sample_bits)
hist_right = [0] * (2**sample_bits)

for i in range(no_frames):
    if i % frame_rate == 0:
        print(f'Processing {i}th frame ({i / no_frames * 100:.3f}%)...', end='\r')
    # read sample data
    d = wav.readframes(1)

    l = int.from_bytes(d[:sample_width], byteorder='little', signed=True)
    r = int.from_bytes(d[sample_width:], byteorder='little', signed=True)

    # build histogram
    hist_left[l] += 1
    hist_right[r] += 1


for lsb_bits in range(1, 16):
    bucket_size = 2 ** lsb_bits

    bucket_left = [0] * bucket_size
    bucket_right = [0] * bucket_size

    for i in range(len(hist_left)):
        bucket = i % bucket_size
        bucket_left[bucket] += hist_left[i]
        bucket_right[bucket] += hist_right[i]

    with open(f'hist_lsb_{bucket_size}.txt', 'w') as fout:
        for i in range(len(bucket_left)):
            idx = i
            if i >= bucket_size / 2:
                idx = i - bucket_size
            print(f'{idx}\t{bucket_left[i]}\t{bucket_right[i]}', file=fout)

for msb_bits in range(1, 16):
    bucket_size = 2 ** msb_bits
    filter_size = 2 ** (sample_bits - msb_bits)

    bucket_left = [0] * bucket_size
    bucket_right = [0] * bucket_size

    for i in range(len(hist_left)):
        bucket = i // filter_size
        bucket_left[bucket] += hist_left[i]
        bucket_right[bucket] += hist_right[i]

    with open(f'hist_msb_{bucket_size}.txt', 'w') as fout:
        for i in range(len(bucket_left)):
            idx = i
            if i >= bucket_size / 2:
                idx = i - bucket_size
            print(f'{idx}\t{bucket_left[i]}\t{bucket_right[i]}', file=fout)