我正在编写WAVE音频文件的基本频率分析,但是当涉及从WAVE帧转换为整数时我遇到了麻烦.

这是我的代码的相关部分：

import wave
track = wave.open('/some_path/my_audio.wav', 'r')

byt_depth = track.getsampwidth() #Byte depth of the file in BYTES
frame_rate = track.getframerate()
buf_size = 512

def byt_sum (word):
#convert a string of n bytes into an int in [0;8**n-1]
    return sum( (256**k)*word[k] for k in range(len(word)) )

raw_buf = track.readframes(buf_size)
'''
One frame is a string of n bytes, where n = byt_depth.
For instance, with a 24bits-encoded file, track.readframe(1) could be:
b'\xff\xfe\xfe'.
raw_buf[n] returns an int in [0;255]
'''

sample_buf = [byt_sum(raw_buf[byt_depth*k:byt_depth*(k+1)])
              - 2**(8*byt_depth-1) for k in range(buf_size)]

问题是：当我为单个正弦信号绘制sample_buf时,我得到了
an alternative, wrecked sine signal.
我无法弄清楚为什么信号与udpside-down重叠.

任何的想法？

P.S.：因为我是法国人,我的英语非常犹豫.如果有丑陋的错误,请随时编辑.

解决方法:

这可能是因为您需要使用无符号值来表示16位样本.见https://en.wikipedia.org/wiki/Pulse-code_modulation

尝试为每个样本添加32767.

您还应该使用python struct module来解码缓冲区.

import struct
buff_size = 512
# 'H' is for unsigned 16 bit integer, try 'h' also
sample_buff = struct.unpack('H'*buf_size, raw_buf)