1#! /usr/bin/env python 2 3""" Create a simple stereo file containing a sine tone at 441 Hz, using only 4python's built-in modules. """ 5 6import wave 7import math 8import struct 9 10 11def create_sine_wave(freq, samplerate, nframes, nchannels): 12 """ create a pure tone (without numpy) """ 13 _x = [0.7 * math.sin(2. * math.pi * freq * t / float(samplerate)) 14 for t in range(nframes)] 15 _x = [int(a * 32767) for a in _x] 16 _x = b''.join([b''.join([struct.pack('h', v) 17 for _ in range(nchannels)]) 18 for v in _x]) 19 return _x 20 21 22def create_test_sound(pathname, freq=441, duration=None, 23 framerate=44100, nchannels=2): 24 """ create a sound file at pathname, overwriting exiting file """ 25 sampwidth = 2 26 nframes = duration or framerate # defaults to 1 second duration 27 fid = wave.open(pathname, 'w') 28 fid.setnchannels(nchannels) 29 fid.setsampwidth(sampwidth) 30 fid.setframerate(framerate) 31 fid.setnframes(nframes) 32 frames = create_sine_wave(freq, framerate, nframes, nchannels) 33 fid.writeframes(frames) 34 fid.close() 35 return 0 36 37 38if __name__ == '__main__': 39 import sys 40 if len(sys.argv) < 2: 41 sys.exit(2) 42 sys.exit(create_test_sound(sys.argv[1])) 43