sine-wave.py

""" Create a synthetic 'sine wave' wave file.

Create a synthetic 'sine wave' wave file with set frequency and length

Tested with Python 2.5.4 and Python 3.1.1

"""

__author__ = "vegaseat"

import math
import wave
import struct

def mkwav(freq=440, data_size=10000, fname="tmp.wav"):
	"""
	create a synthetic 'sine wave' wave file with frequency freq
	file fname has a length of about data_size * 2
	"""
	frate = 11025.0  # framerate as a float
	amp = 8000.0     # multiplier for amplitude
   # make a sine list ...
	sine_list = []
	for x in range(data_size):
		sine_list.append(math.sin(2*math.pi*freq*(x/frate)))
	print(sine_list)
	return sine_list

def writewav(sine_list):
	wav_file = wave.open(fname, "w")
	# give required parameters
	nchannels = 1
	sampwidth = 2
	framerate = int(frate)
	nframes = data_size
	comptype = "NONE"
	compname = "not compressed"
	# set all the parameters at once
	wav_file.setparams((nchannels, sampwidth, framerate, nframes,
		comptype, compname))
	# now write out the file ...
	for s in sine_list:
		# write the audio frames to file
		wav_file.writeframes(struct.pack('h', int(s*amp/2)))
	wav_file.close()
	print( "%s written" % fname )

if __name__ == '__main__':
	# set some variables ...
	freq = 440.0
	# data size, file size will be about 2 times that
	# duration is about 4 seconds for a data_size of 40000
	data_size = 40000

	# write the synthetic wave file to ...
	fname = "test.wav"

	mkwav(freq, data_size, fname)