Support for mixes of multiple sounds

platypush/plugins/sound/core.py

@@ -1,6 +1,14 @@
+"""
+.. moduleauthor:: Fabio Manganiello <blacklight86@gmail.com>
+"""
+
+import json
+import math
+
+
 class Sound(object):
     """
-    Class model a synthetic sound that can be played through the audio device
+    Models a basic synthetic sound that can be played through an audio device
     """
 
     STANDARD_A_FREQUENCY = 440.0
@@ -11,11 +19,12 @@ class Sound(object):
 
     midi_note = None
     frequency = None
+    phase = 0.0
     gain = 1.0
     duration = None
 
-    def __init__(self, midi_note=midi_note, frequency=None, gain=gain,
-                 duration=duration, A_frequency=STANDARD_A_FREQUENCY):
+    def __init__(self, midi_note=midi_note, frequency=None, phase=phase,
+                 gain=gain, duration=duration, A_frequency=STANDARD_A_FREQUENCY):
         """
         You can construct a sound either from a MIDI note or a base frequency
 
@@ -26,6 +35,9 @@ class Sound(object):
         :param frequency: Sound base frequency in Hz
         :type frequency: float
 
+        :param phase: Wave phase shift as a multiple of pi (default: 0.0)
+        :type phase: float
+
         :param gain: Note gain/volume between 0.0 and 1.0 (default: 1.0)
         :type gain: float
 
@@ -53,6 +65,7 @@ class Sound(object):
             raise RuntimeError('Please specify either a MIDI note or a base ' +
                                'frequency')
 
+        self.phase = phase
         self.gain = gain
         self.duration = duration
 
@@ -92,10 +105,10 @@ class Sound(object):
         """
         Get the wave binary data associated to this sound
 
-        :param t_start: Start offset for the sine wave in seconds. Default: 0
+        :param t_start: Start offset for the wave in seconds. Default: 0
         :type t_start: float
 
-        :param t_end: End offset for the sine wave in seconds. Default: 0
+        :param t_end: End offset for the wave in seconds. Default: 0
         :type t_end: float
 
         :param samplerate: Audio sample rate. Default: 44100 Hz
@@ -108,18 +121,17 @@ class Sound(object):
         x = np.linspace(t_start, t_end, int((t_end-t_start)*samplerate))
 
         x = x.reshape(len(x), 1)
-        return self.gain * np.sin(2 * np.pi * self.frequency * x)
+        return self.gain * np.sin((2*np.pi*self.frequency*x) + np.pi*self.phase)
+
+
+    def __iter__(self):
+        for attr in ['midi_note', 'frequency', 'gain', 'duration']:
+            yield (attr, getattr(self, attr))
 
 
     def __str__(self):
-        import json
+        return json.dumps(dict(self))
 
-        return json.dumps({
-            'midi_note': midi_note,
-            'frequency': frequency,
-            'gain': gain,
-            'duration': duration,
-        })
 
     @classmethod
     def build(cls, *args, **kwargs):
@@ -128,8 +140,6 @@ class Sound(object):
         key-value representation
         """
 
-        import json
-
         if args:
             if isinstance(args[0], cls):
                 return args[0]
@@ -143,4 +153,84 @@ class Sound(object):
         raise RuntimeError('Usage: {}'.format(__doc__))
 
 
+class Mix(object):
+    """
+    This class models a set of mixed :class:`Sound` instances that can be played
+    through an audio stream to an audio device
+    """
+
+    _sounds = []
+
+    def __init__(self, *sounds):
+        for sound in sounds:
+            self.add(sound)
+
+
+    def __iter__(self):
+        for sound in self._sounds:
+            yield dict(sound)
+
+
+    def __str__(self):
+        return json.dumps(list(self))
+
+
+    def add(self, sound):
+        self._sounds.append(Sound.build(sound))
+
+
+    def get_wave(self, t_start=0., t_end=0., normalize_range=(-1.0, 1.0),
+                 on_clip='scale', samplerate=Sound._DEFAULT_SAMPLERATE):
+        """
+        Get the wave binary data associated to this mix
+
+        :param t_start: Start offset for the wave in seconds. Default: 0
+        :type t_start: float
+
+        :param t_end: End offset for the wave in seconds. Default: 0
+        :type t_end: float
+
+        :param normalize_range: Normalization range. If set the gain values of the
+            wave will be normalized to fit into the specified range if it
+            "clips" above or below.  Default: ``(-1.0, 1.0)``
+        :type normalize_range: list[float]
+
+        :param on_clip: Action to take on wave clipping if ``normalize_range``
+            is set. Possible values: "``scale``" (scale down the frame to remove
+            the clipping) or "``clip``" (saturate the values above/below range).
+            Default: "``scale``".
+        :param samplerate: Audio sample rate. Default: 44100 Hz
+        :type samplerate: int
+
+        :returns: A numpy.ndarray[n,1] with the raw float values
+        """
+
+        wave = None
+
+        for sound in self._sounds:
+            sound_wave = sound.get_wave(t_start=t_start, t_end=t_end,
+                                        samplerate=samplerate)
+
+            if wave is None:
+                wave = sound_wave
+            else:
+                wave += sound_wave
+
+        if normalize_range:
+            scale_factor = (normalize_range[1]-normalize_range[0]) / \
+                (wave.max()-wave.min())
+
+            if scale_factor < 1.0:  # Wave clipping
+                if on_clip == 'scale':
+                    wave = scale_factor * wave
+                elif on_clip == 'clip':
+                    wave[wave < normalize_range[0]] = normalize_range[0]
+                    wave[wave > normalize_range[1]] = normalize_range[1]
+                else:
+                    raise RuntimeError('Supported values for "on_clip": ' +
+                                       '"scale" or "clip"')
+
+        return wave
+
+
 # vim:sw=4:ts=4:et: