musicapi / utils.py
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Create utils.py
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import base64
import numpy as np
from io import BytesIO
def decode(base64_str: str) -> bytes:
binary_string = base64.b64decode(base64_str)
return binary_string
def pcm_to_wav(pcm_data: bytes, num_channels: int, sample_rate: int, bits_per_sample: int) -> bytes:
data_size = len(pcm_data)
buffer = bytearray(44 + data_size)
view = memoryview(buffer)
def write_string(offset: int, string: str):
for i, char in enumerate(string):
view[offset + i] = ord(char)
write_string(0, 'RIFF')
view[4:8] = (36 + data_size).to_bytes(4, 'little')
write_string(8, 'WAVE')
write_string(12, 'fmt ')
view[16:20] = (16).to_bytes(4, 'little')
view[20:22] = (1).to_bytes(2, 'little')
view[22:24] = num_channels.to_bytes(2, 'little')
view[24:28] = sample_rate.to_bytes(4, 'little')
view[28:32] = (sample_rate * num_channels * (bits_per_sample // 8)).to_bytes(4, 'little')
view[32:34] = (num_channels * (bits_per_sample // 8)).to_bytes(2, 'little')
view[34:36] = bits_per_sample.to_bytes(2, 'little')
write_string(36, 'data')
view[40:44] = data_size.to_bytes(4, 'little')
view[44:] = pcm_data
return bytes(buffer)