Guido van Rossum | c636014 | 1990-10-13 19:23:40 +0000 | [diff] [blame] | 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 |
Guido van Rossum | bdfcfcc | 1992-01-01 19:35:13 +0000 | [diff] [blame] | 72 | if ib == ja: |
Guido van Rossum | c636014 | 1990-10-13 19:23:40 +0000 | [diff] [blame] | 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) |