ref: b610be5271280b1eaefb00f6bb7272a4123092f4
parent: 60384e9334401a70cbd694721bd77c32f71fa91f
author: Paul Brossier <piem@piem.org>
date: Thu Nov 29 11:08:24 EST 2018
[tests] pure python create_sine_wave
--- a/tests/create_tests_source.py
+++ b/tests/create_tests_source.py
@@ -1,25 +1,28 @@
#! /usr/bin/env python
""" Create a simple stereo file containing a sine tone at 441 Hz, using only
-numpy and python's native wave module. """
+python's built-in modules. """
import wave
-import numpy as np
+import math
+import struct
def create_sine_wave(freq, samplerate, nframes, nchannels):
- """ create a pure tone """
- # samples indices
- _t = np.tile(np.arange(nframes), (nchannels, 1))
- # sine wave generation
- _x = 0.7 * np.sin(2. * np.pi * freq * _t / float(samplerate))
- # conversion to int and channel interleaving
- return (_x * 32767.).astype(np.int16).T.flatten()
+ """ create a pure tone (without numpy) """
+ _x = [0.7 * math.sin(2. * math.pi * freq * t / float(samplerate))
+ for t in range(nframes)]
+ _x = [int(a * 32767) for a in _x]
+ _x = b''.join([b''.join([struct.pack('h', v)+ for _ in range(nchannels)])
+ for v in _x])
+ return _x
def create_test_sound(pathname, freq=441, duration=None,
- sampwidth=2, framerate=44100, nchannels=2):
+ framerate=44100, nchannels=2):
""" create a sound file at pathname, overwriting exiting file """
+ sampwidth = 2
nframes = duration or framerate # defaults to 1 second duration
fid = wave.open(pathname, 'w')
fid.setnchannels(nchannels)
@@ -27,7 +30,7 @@
fid.setframerate(framerate)
fid.setnframes(nframes)
frames = create_sine_wave(freq, framerate, nframes, nchannels)
- fid.writeframes(frames.tobytes())
+ fid.writeframes(frames)
fid.close()
return 0