Added example file for pitch shifting

examples/audio/pitch.py

@@ -0,0 +1,44 @@
+# encoding: utf8
+
+from kivy.app import App
+from kivy.lang import Builder
+from kivy.clock import Clock
+from kivy.core.audio import SoundLoader
+from kivy.uix.boxlayout import BoxLayout
+from kivy.uix.button import Button
+
+from sys import version_info
+
+
+NOTES = (
+    ('Do',  1),
+    ('Ré',  9/8.),
+    ('Mi',  5/4.),
+    ('Fa',  4/3.),
+    ('Sol', 3/2.),
+    ('La',  5/3.),
+    ('Si',  15/8.),
+)
+
+class Test(App):
+    def build(self):
+        self.sound = SoundLoader.load(
+            '/usr/lib64/python{}.{}/test/audiodata/pluck-pcm32.wav'
+            .format(*version_info[0:2])
+        )
+        print(self.sound.source)
+        root = BoxLayout()
+        for octave in range(3):
+            for note, pitch in NOTES:
+                button = Button(text=note)
+                button.pitch = pitch * 2 ** octave
+                button.bind(on_release=self.play_note)
+                root.add_widget(button)
+        return root
+
+    def play_note(self, button):
+        print(button.text, button.pitch)
+        self.sound.pitch = button.pitch
+        self.sound.play()
+
+Test().run()