python手记(45)

python 声音编辑，减少音量

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#http://blog.csdn.net/myhaspl
#code:[e-mail]
import wave
import pylab as pl
import numpy as np

print 'http://blog.csdn.net/myhaspl'
print '[e-mail]'
print  

print 'working...' 

def wavechange(x,dwmax,dwmin):
    if x!=0:
        if abs(x)<dwmax and abs(x)>dwmin:
            x=x*0.5
        else:
            x=x*0.2
    return x

# 打开WAV文档
f = wave.open(r"speak.wav", "rb")
fo = wave.open(r"jg.wav", "wb")
# 读取波形数据
# (nchannels, sampwidth, framerate, nframes, comptype, compname)
params = f.getparams()
nchannels, sampwidth, framerate, nframes = params[:4]
print "read wav data...."
str_data = f.readframes(nframes)

#将波形数据转换为数组，并更改
print "update wav data...."
wave_data = np.fromstring(str_data, dtype=np.short)
params = f.getparams()
nchannels, sampwidth, framerate, nframes = params[:4]
str_data = f.readframes(nframes)

#降低声音
change_dwmax=wave_data.max()/100*1
change_dwmin=wave_data.max()/100*0.5
wave_change = np.frompyfunc(wavechange,3,1)
new_wave_data =wave_change(wave_data,change_dwmax,change_dwmin)
new_wave_data =new_wave_data.astype(wave_data.dtype)
new_str_data=new_wave_data.tostring()
#写波形数据参数
print "save new wav files...."
fo.setnchannels(nchannels)
fo.setframerate(framerate)
fo.setsampwidth(sampwidth)
fo.writeframes(new_str_data)

# 绘制波形
wave_data.shape = -1, 2
wave_data = wave_data.T
time = np.arange(0, nframes) * (1.0 / framerate)
pl.subplot(221)
pl.plot(time, wave_data[0])
pl.subplot(222)
pl.plot(time, wave_data[1], c="g")
pl.xlabel("time (seconds)")
pl.show()

# 绘制波形
new_wave_data.shape = -1, 2
new_wave_data =new_wave_data.T
new_time = np.arange(0, nframes) * (1.0 / framerate)
pl.subplot(223)
pl.plot(new_time,new_wave_data[0])
pl.subplot(224)
pl.plot(new_time, new_wave_data[1], c="g")
pl.xlabel("time (seconds)")
pl.show()