python/demos/demo_create_test_sounds.py: add script to create simple sound files...

diff --git a/python/demos/demo_create_test_sounds.py b/python/demos/demo_create_test_sounds.py
new file mode 100755 (executable)
index 0000000..50fdb6e
--- /dev/null
+++ b/python/demos/demo_create_test_sounds.py
@@ -0,0 +1,50 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys, os
+import numpy as np
+from aubio import fvec, sink, float_type
+
+if __name__ == '__main__':
+    if len(sys.argv) < 1:
+        print('usage: %s' % sys.argv[0])
+        sys.exit(1)
+
+    samplerate = 44100
+    hop_size = 256
+
+    # create python/tests/sounds if needed
+    output_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    output_dir = os.path.join(output_dir, 'tests', 'sounds')
+    if not os.path.isdir(output_dir):
+        os.makedirs(output_dir)
+
+    filenames = ['44100Hz_1f_silence.wav',
+                 '22050Hz_5s_brownnoise.wav',
+                 '32000Hz_127f_sine440.wav',
+                ]
+    samplerates = [44100, 22050, 32000]
+    durations = [1, 5*22050, 127]
+
+    for fname, samplerate, duration in zip(filenames, samplerates, durations):
+        output_name = os.path.join(output_dir, fname)
+        g = sink(output_name, samplerate)
+        total_frames = 0
+        while total_frames < duration:
+            write = min(hop_size, duration - total_frames)
+            if 'brownnoise' in fname:
+                vec = np.random.rand(write).astype(float_type) * 2. - 1.
+            elif 'sine' in fname:
+                freq = 440
+                t = np.arange(write).astype(float_type) + total_frames
+                vec = np.sin(2. * np.pi * freq * t / float(samplerate))
+            else:
+                # silence
+                vec = fvec(write)
+            g(vec, write)
+            total_frames += write
+        outstr = "wrote {:2f}s".format(total_frames / float(samplerate))
+        outstr += " ({:d} frames".format(total_frames)
+        outstr += " at {:d}Hz)".format(g.samplerate)
+        outstr += " to {:s}".format(g.uri)
+        print outstr