最近研究的，我用的是python3.3, 用matplotlib畫圖，
下面程式碼演示分析pcm檔案，如果是wave檔案，把wave的檔案頭去掉就是pcm檔案了。
程式碼如下
1 # -*- coding:utf-8 -*- 2 3 import array 4 import os 5 from matplotlib import pyplot 6 7 fileName = 'e:/music/qianqian.pcm' # 2 channel, 16 bit per sample 8 file = open(fileName, 'rb') 9 base = 1 / (1<<15) 10 11 shortArray = array.array('h') # int16 12 size = int(os.path.getsize(fileName) / shortArray.itemsize) 13 count = int(size / 2) 14 shortArray.fromfile(file, size) # faster than struct.unpack 15 file.close() 16 leftChannel = shortArray[::2] 17 rightChannel = shortArray[1::2] 18 19 def showPCM(leftChannel, rightChannel, start = 0, end = 5000): 20 fig = pyplot.figure(1) 21 22 pyplot.subplot(211) 23 pyplot.title('pcm left channel [{0}-{1}] max[{2}]'.format(start, end, count)) 24 pyplot.plot(range(start, end), leftChannel[start:end]) 25 26 pyplot.subplot(212) 27 pyplot.title('pcm right channel [{0}-{1}] max[{2}]'.format(start, end, count)) 28 pyplot.plot(range(start, end), rightChannel[start:end]) 29 30 pyplot.show() 31 # fig.savefig('pcm.pdf') # save figure to pdf file 32 33 showPCM(leftChannel, rightChannel, 0, count)
另一種分析方法，用struct.unpack，但讀取要比上一種慢很多
1 # -*- coding:utf-8 -*- 2 3 import struct 4 from matplotlib import pyplot 5 6 file = open('e:/music/qianqian.pcm', 'rb') # if file is too large, pyplot may overflow 7 count = 0 8 total = 0 9 base = 1 / (1<<15) 10 maxl = 0 11 minl = 0 12 maxr = 0 13 minr = 0 14 larray = [] 15 rarray = [] 16 # file has two channels, 16 bit per sample 17 while True: 18 lr = file.read(4) 19 if len(lr) < 4: 20 break 21 count += 1 22 lvalue = struct.unpack('h', lr[:2])[0] * base 23 larray.append(lvalue) 24 if lvalue > maxl: 25 maxl = lvalue 26 if lvalue < minl: 27 minl = lvalue 28 total += lvalue 29 rvalue = struct.unpack('h', lr[2:])[0] * base 30 rarray.append(rvalue) 31 if rvalue > maxr: 32 maxr = rvalue 33 if rvalue < minr: 34 minr = rvalue 35 36 file.close() 37 avarage = total / count 38 print(count, total, avarage) 39 print('max = {0} min = {1}'.format(maxl, minl)) 40 41 fig = pyplot.figure(1) 42 pyplot.subplot(211) 43 pyplot.title('pcm left channel') 44 pyplot.plot(range(count), larray) 45 pyplot.subplot(212) 46 pyplot.title('pcm right channel') 47 pyplot.plot(range(count), rarray) 48 pyplot.show() 49 # fig.savefig('pcm.pdf')
程式碼及pcm下載：http://pan.baidu.com/s/1bp42TOj
下面這個地址也有一個例子：http://stackoverflow.com/questions/18625085/how-to-plot-a-wav-file可以看看。