Question

我已经获得了一个连续水下录制的大型WAV文件，我想将其转换为numpy数组进行分析。我正在努力做到这一点。

到目前为止，我有：

import numpy as np
import scipy as sp
import wave as wv
import struct

wavefile = wv.open(filename,'r')
(nchannels,sampwidth,framerate,nframes,comptype,compname) = wavefile.getparams()

// read a sample as example

wavedata =wavefile.readframes(1)

第一帧看起来像这样：'\ xcd \ xbc \ xff @ \ x01 \ x00'。我试图使用struct解压缩但是无论我做什么，我都会收到以下错误：“ str size与格式不匹配”。我想这与Python struct无法处理24位数据有关。

wave文件的参数如下所示：

nchannels = 2
sampwidth = 3
帧率= 48000
将为nframes = 283516532L
comptype = 'NONE'
compname ='not compressed'

有人知道如何将24位立体声WAV文件读入一个numpy数组吗？

Answer 1

这是一个循环，用于处理具有任意数量通道的2,3和4字节WAV文件：

def dataFromWave(fname):
""" return list with interleaved samples """
    f = wave.open(fname, 'rb')
    chans = f.getnchannels()
    samps = f.getnframes()
    sampwidth = f.getsampwidth()
    if  sampwidth == 3: #have to read this one sample at a time
        s = ''
        for k in xrange(samps):
            fr = f.readframes(1)
            for c in xrange(0,3*chans,3):                
                s += '\0'+fr[c:(c+3)] # put TRAILING 0 to make 32-bit (file is little-endian)
    else:
        s = f.readframes(samps)
    f.close()
    unpstr = '<{0}{1}'.format(samps*chans, {1:'b',2:'h',3:'i',4:'i',8:'q'}[sampwidth])
    x = list(struct.unpack(unpstr, s))
    if sampwidth == 3:
        x = [k >> 8 for k in x] #downshift to get +/- 2^24 with sign extension
    return x

Answer 2

对于那些有类似问题的人，我发布了我的解决方案。请注意，这会将24位波形文件转换为带符号的浮点数numpy数组。只转换为整数时将/ int2float部分保留。

frames = wavfile.readframes(nsamples)

ch1 = np.zeros(nsamples)
ch2 = np.zeros(nsamples)
int2float = (2**23)-1

for x in np.arange(int(nsamples)):
    ch1_24bit_sample = frames[x*6:x*6+3]
    ch2_24bit_sample = frames[x*6+3:x*6+6]
    ch1_32bit_sample = bit24_2_32(ch1_24bit_sample)
    ch2_32bit_sample = bit24_2_32(ch2_24bit_sample)
    ch1[x]=struct.unpack('i',ch_32bit_sample)[0]
    ch2[x]=struct.unpack('i',ch_32bit_sample)[0]
    ch1[x]=ch1[x]/int2float
    ch2[x]=ch2[x]/int2float

def bit24_2_32(strbytes):
    if strbytes[2] < '\x80':
       return strbytes+'\x00'
    else:
       return strbytes+'\xff'

Answer 3

这是一个老问题，但如果有人需要其他选项并且使用外部模块没有限制，那么您可以使用librosa

myNdArray = librosa.core.load(wav_path, sr=sample_rate)[0]

将3字节立体声WAV文件转换为numpy数组

3 个答案: