Python Scipy FFT WAV文件 [英] Python Scipy FFT wav files

问题描述

我有一些wav文件.我想使用SciPy FFT绘制这些wav文件的频谱图.我将如何去做?

I have a handful of wav files. I'd like to use SciPy FFT to plot the frequency spectrum of these wav files. How would I go about doing this?

推荐答案

Python提供了一些api来相当快地完成此操作.我从此链接下载了绵羊哭声wav文件.您可以将其保存在桌面上，并在终端中的cd上保存.在python提示符下的这些行应该足够了:(忽略>>>)

Python provides several api to do this fairly quickly. I download the sheep-bleats wav file from this link. You can save it on the desktop and cd there within terminal. These lines in the python prompt should be enough: (omit >>>)

import matplotlib.pyplot as plt
from scipy.fftpack import fft
from scipy.io import wavfile # get the api
fs, data = wavfile.read('test.wav') # load the data
a = data.T[0] # this is a two channel soundtrack, I get the first track
b=[(ele/2**8.)*2-1 for ele in a] # this is 8-bit track, b is now normalized on [-1,1)
c = fft(b) # calculate fourier transform (complex numbers list)
d = len(c)/2  # you only need half of the fft list (real signal symmetry)
plt.plot(abs(c[:(d-1)]),'r') 
plt.show()

这是输入信号的图:

Here is a plot for the input signal:

这是光谱

要获得正确的输出，必须将xlabel转换为频谱图的频率.

For the correct output, you will have to convert the xlabelto the frequency for the spectrum plot.

k = arange(len(data))
T = len(data)/fs  # where fs is the sampling frequency
frqLabel = k/T  

如果必须处理大量文件，则可以将其实现为一个函数: 将这些行放入test2.py:

If you are have to deal with a bunch of files, you can implement this as a function: put these lines in the test2.py:

import matplotlib.pyplot as plt
from scipy.io import wavfile # get the api
from scipy.fftpack import fft
from pylab import *

def f(filename):
    fs, data = wavfile.read(filename) # load the data
    a = data.T[0] # this is a two channel soundtrack, I get the first track
    b=[(ele/2**8.)*2-1 for ele in a] # this is 8-bit track, b is now normalized on [-1,1)
    c = fft(b) # create a list of complex number
    d = len(c)/2  # you only need half of the fft list
    plt.plot(abs(c[:(d-1)]),'r')
    savefig(filename+'.png',bbox_inches='tight')

说，我在当前工作目录中有test.wav和test2.wav，在python提示符界面中的以下命令就足够了: 导入测试2 map(test2.f，['test.wav'，'test2.wav'])

Say, I have test.wav and test2.wav in the current working dir, the following command in python prompt interface is sufficient: import test2 map(test2.f, ['test.wav','test2.wav'])

假设您有100个此类文件，并且不想单独键入它们的名称，则需要glob软件包:

Assuming you have 100 such files and you do not want to type their names individually, you need the glob package:

import glob
import test2
files = glob.glob('./*.wav')
for ele in files:
    f(ele)
quit()

如果.wav文件不是同一位，则需要在test2.f中添加getparams.

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