3 # Generate imperfect sine waves
5 # Design notes. Produces ~= (user requested) s of raw audio
6 # We're aiming for an 8-bit'ish effect, so we're going with
7 # 8125 Hz, 8 bit sampling, but faking it out to
8 # CDDA output (44100 Hz, 16 bit signed) for easier conversion to ogg
9 # by multiply the value by 256 (after roundin) and repeating it 4 times.
19 def gen_sine(freq, secs, volume):
20 filename = 'beep%s.pcm' % freq
21 # We generate freq cycles and sample that OUTPUT_RATE times
22 per_cycle = OUTPUT_RATE // freq
24 for x in range(per_cycle):
25 rad = float(x) / per_cycle * 2 * math.pi
26 y = 256 * int(volume * math.sin(rad))
27 data.extend([struct.pack('<i', y)] * 4)
28 output = open(filename, 'wb')
29 # This is correct because OUTPUT_RATE = CDDA rate / 4 and we repeat
30 # the samples 4 times, so this works out to CDDA rate
31 for x in range(int(freq * secs)):
32 output.write(b''.join(data))
34 print ('Wrote output to %s' % filename)
38 print ('Unexpected input')
39 print ('Usage gen_sound <freq> [<length>] [<volume>]')
40 print (' where <freq> is the frequency in Hz (int)')
41 print (' [<length>] is the time in seconds (float) - default 0.25')
42 print (' and [<volume>] is the volume (integer between 0 and 127)'
43 ' - default %s' % DEFAULT_VOL)
46 if __name__ == "__main__":
48 freq = int(sys.argv[1])
50 secs = float(sys.argv[2])
54 volume = int(sys.argv[3])
57 except Exception as exc:
59 print ('Error was: %s' % exc)
62 if volume > 128 or volume < 0:
64 print ('Invalid volume: %s' % volume)
67 if freq > 2000 or freq < 100:
69 print ('Invalid freq: %s' % volume)
72 gen_sine(freq, secs, volume)