Python：将单波文件转换为立体声

Question

我正在寻找在Python中将波形文件从单声道转换为立体声。最后应该有两个相同的左右声道单声道信息。我的代码不起作用。我只有输入信息的左声道，右声道是空的。有什么建议么？

import struct, wave 
import numpy as np 

def make_stereo(file1, output): 
    def everyOther (v, offset=0): 
     return [v[i] for i in range(offset, len(v), 2)] 
    ifile = wave.open(file1) 
    print ifile.getparams() 
    # (1, 2, 44100, 2013900, 'NONE', 'not compressed') 
    (nchannels, sampwidth, framerate, nframes, comptype, compname) = ifile.getparams() 
    frames = ifile.readframes(nframes * nchannels) 
    ifile.close() 
    out = struct.unpack_from("%dh" % nframes * nchannels, frames) 
    # Convert 2 channels to numpy arrays 
    if nchannels == 2: 
     left = np.array(list(everyOther(out, 0))) 
     right = np.array(list(everyOther(out, 1))) 
    else: 
     left = np.array(out) 
     right = left 
    ofile = wave.open(output, 'w') 
    ofile.setparams((2, sampwidth, framerate, nframes, comptype, compname)) 
    ofile.writeframes(left.tostring()) 
    # ofile.writeframes(right.tostring()) 
    ofile.close() 

make_stereo("Input.wav", "Output.wav") 

Answer 1

使用numpy因为这是众所周知的猎象枪射击一只苍蝇，除非，也许，如果您有性能问题。

array很容易推理和使用。我不是在我的音频电脑上，但是使用阵列的程序的翻译应该是这样的：

import wave, array 

def make_stereo(file1, output): 
    ifile = wave.open(file1) 
    print ifile.getparams() 
    # (1, 2, 44100, 2013900, 'NONE', 'not compressed') 
    (nchannels, sampwidth, framerate, nframes, comptype, compname) = ifile.getparams() 
    assert comptype == 'NONE' # Compressed not supported yet 
    array_type = {1:'B', 2: 'h', 4: 'l'}[sampwidth] 
    left_channel = array.array(array_type, ifile.readframes(nframes))[::nchannels] 
    ifile.close() 

    stereo = 2 * left_channel 
    stereo[0::2] = stereo[1::2] = left_channel 

    ofile = wave.open(output, 'w') 
    ofile.setparams((2, sampwidth, framerate, nframes, comptype, compname)) 
    ofile.writeframes(stereo.tostring()) 
    ofile.close() 

make_stereo("Input.wav", "Output.wav")