Lib/irix5/auds.py

   1 import audio
   2
   3 RATE = 8192
   4
   5 # Initialize the audio stuff
   6 audio.setrate(3)
   7 audio.setoutgain(100)   # for speaker
   8
   9 play = audio.write
  10
  11 def samp(n):
  12         savegain = audio.getoutgain()
  13         try:
  14                 audio.setoutgain(0)
  15                 x = raw_input('Hit Enter to sample ' + `n` + ' seconds: ')
  16                 return audio.read(n*RATE)
  17         finally:
  18                 audio.setoutgain(savegain)
  19
  20 def echo(s, delay, gain):
  21         return s[:delay] + audio.add(s[delay:], audio.amplify(s, gain, gain))
  22
  23 def save(s, file):
  24         f = open(file, 'w')
  25         f.write(s)
  26
  27 def load(file):
  28         return loadfp(open(file, 'r'))
  29
  30 def loadfp(fp):
  31         s = ''
  32         while 1:
  33                 buf = fp.read(16*1024)
  34                 if not buf: break
  35                 s = s + buf
  36         return s
  37
  38 def unbias(s):
  39         if not s: return s
  40         a = audio.chr2num(s)
  41         sum = 0
  42         for i in a: sum = sum + i
  43         bias = (sum + len(a)/2) / len(a)
  44         print 'Bias value:', bias
  45         if bias:
  46                 for i in range(len(a)):
  47                         a[i] = a[i] - bias
  48                 s = audio.num2chr(a)
  49         return s
  50
  51 # Stretch by a/b.
  52 # Think of this as converting the sampling rate from a samples/sec
  53 # to b samples/sec.  Or, if the input is a bytes long, the output
  54 # will be b bytes long.
  55 #
  56 def stretch(s, a, b):
  57         y = audio.chr2num(s)
  58         m = len(y)
  59         out = []
  60         n = m * b / a
  61         # i, j will walk through y and out (step 1)
  62         # ib, ja are i*b, j*a and are kept as close together as possible
  63         i, ib = 0, 0
  64         j, ja = 0, 0
  65         for j in range(n):
  66                 ja = ja+a
  67                 while ib < ja:
  68                         i = i+1
  69                         ib = ib+b
  70                 if i >= m:
  71                         break
  72                 if ib == ja:
  73                         out.append(y[i])
  74                 else:
  75                         out.append((y[i]*(ja-(ib-b)) + y[i-1]*(ib-ja)) / b)
  76         return audio.num2chr(out)
  77
  78 def sinus(freq): # return a 1-second sine wave
  79         from math import sin, pi
  80         factor = 2.0*pi*float(freq)/float(RATE)
  81         list = range(RATE)
  82         for i in list:
  83                 list[i] = int(sin(float(i) * factor) * 127.0)
  84         return audio.num2chr(list)
  85
  86 def softclip(s):
  87         if '\177' not in s and '\200' not in s:
  88                 return s
  89         num = audio.chr2num(s)
  90         extremes = (-128, 127)
  91         for i in range(1, len(num)-1):
  92                 if num[i] in extremes:
  93                         num[i] = (num[i-1] + num[i+1]) / 2
  94         return audio.num2chr(num)
  95
  96 def demo():
  97         gday = load('gday')[1000:6000]
  98         save(gday, 'gday0')
  99         gg = [gday]
 100         for i in range(1, 10):
 101                 for g in gg: play(g)
 102                 g = stretch(gday, 10, 10-i)
 103                 save(g, 'gday' + `i`)
 104                 gg.append(g)
 105         while 1:
 106                 for g in gg: play(g)