- Added frames throttling support on Leap Motion backend

- Moved the Leap listener to another process to prevent it from hanging the other backends
- Added support for sound and mix frequency analysis

platypush/backend/sensor/leap.py

@@ -1,5 +1,8 @@
 import time
 
+from threading import Timer
+from multiprocessing import Process
+
 import Leap
 
 from platypush.backend import Backend
@@ -21,6 +24,12 @@ class SensorLeapBackend(Backend):
     instructions at https://www.leapmotion.com/setup/) and the `leapd` daemon
     running to recognize your controller.
 
+    Requires:
+
+        * The Redis backend enabled
+        * The Leap Motion SDK compiled with Python 3 support, see my port at https://github.com:BlackLight/leap-sdk-python3.git
+        * The `leapd` daemon to be running and your Leap Motion connected
+
     Triggers:
 
         * :class:`platypush.message.event.sensor.leap.LeapFrameEvent` when a new frame is received
@@ -30,6 +39,8 @@ class SensorLeapBackend(Backend):
         * :class:`platypush.message.event.sensor.leap.LeapDisconnectEvent` when a Leap Motion device disconnects
     """
 
+    _listener_proc = None
+
     def __init__(self,
                  position_ranges=[
                      [-300.0, 300.0],  # x axis
@@ -37,6 +48,7 @@ class SensorLeapBackend(Backend):
                      [-300.0, 300.0],  # z axis
                  ],
                  position_tolerance=0.0,  # Position variation tolerance in %
+                 frames_throttle_secs=None,
                  *args, **kwargs):
         """
         :param position_ranges: It specifies how wide the hand space (x, y and z axes) should be in millimiters.
@@ -53,46 +65,76 @@ class SensorLeapBackend(Backend):
 
         :param position_tolerance: % of change between a frame and the next to really consider the next frame as a new one (default: 0)
         :type position_tolerance: float
+
+        :param frames_throttle_secs: If set, the frame events will be throttled
+            and pushed to the main queue at the specified rate. Good to set if
+            you want to connect Leap Motion events to actions that have a lower
+            throughput (the Leap Motion can send a lot of frames per second).
+            Default: None (no throttling)
+        :type frames_throttle_secs: float
         """
 
         super().__init__(*args, **kwargs)
 
         self.position_ranges = position_ranges
         self.position_tolerance = position_tolerance
+        self.frames_throttle_secs = frames_throttle_secs
 
 
     def run(self):
         super().run()
 
-        listener = LeapListener(position_ranges=self.position_ranges,
+        def _listener_process():
-                                position_tolerance=self.position_tolerance)
+            listener = LeapListener(position_ranges=self.position_ranges,
+                                    position_tolerance=self.position_tolerance,
+                                    frames_throttle_secs=self.frames_throttle_secs,
+                                    logger=self.logger)
 
-        controller = Leap.Controller()
+            controller = Leap.Controller()
 
-        if not controller:
+            if not controller:
-            raise RuntimeError('No Leap Motion controller found - is your ' +
+                raise RuntimeError('No Leap Motion controller found - is your ' +
-                               'device connected and is leapd running?')
+                                'device connected and is leapd running?')
 
-        controller.add_listener(listener)
+            controller.add_listener(listener)
-        self.logger.info('Leap Motion backend initialized')
+            self.logger.info('Leap Motion backend initialized')
 
-        try:
             while not self.should_stop():
                 time.sleep(0.1)
-        finally:
-            controller.remove_listener(listener)
 
+        time.sleep(1)
+        self._listener_proc = Process(target=_listener_process)
+        self._listener_proc.start()
+        self._listener_proc.join()
+
+
+class LeapFuture(Timer):
+    def __init__(self, seconds, listener, event):
+        self.listener = listener
+        self.event = event
+
+        super().__init__(seconds, self._callback_wrapper())
+
+    def _callback_wrapper(self):
+        def _callback():
+            self.listener._send_event(self.event)
+        return _callback
 
 
 class LeapListener(Leap.Listener):
-    def __init__(self, position_ranges, position_tolerance, *args, **kwargs):
+    def __init__(self, position_ranges, position_tolerance, logger,
+                 frames_throttle_secs=None, *args, **kwargs):
         super().__init__(*args, **kwargs)
+
         self.prev_frame = None
         self.position_ranges = position_ranges
         self.position_tolerance = position_tolerance
+        self.frames_throttle_secs = frames_throttle_secs
+        self.logger = logger
+        self.running_future = None
 
 
-    def send_event(self, event):
+    def _send_event(self, event):
         backend = get_backend('redis')
         if not backend:
             self.logger.warning('Redis backend not configured, I cannot propagate the following event: {}'.format(event))
@@ -101,6 +143,16 @@ class LeapListener(Leap.Listener):
         backend.send_message(event)
 
 
+    def send_event(self, event):
+        if self.frames_throttle_secs:
+            if not self.running_future or not self.running_future.is_alive():
+                self.running_future = LeapFuture(seconds=self.frames_throttle_secs,
+                                                  listener=self, event=event)
+                self.running_future.start()
+        else:
+            self._send_event(event)
+
+
     def on_init(self, controller):
         self.prev_frame = None
         self.logger.info('Leap controller listener initialized')

platypush/plugins/sound/__init__.py

@@ -155,7 +155,7 @@ class SoundPlugin(Plugin):
                 data = q.get_nowait()
             except queue.Empty:
                 self.logger.warning('Buffer is empty: increase buffersize?')
-                return
+                raise sd.CallbackAbort
 
             if len(data) < len(outdata):
                 outdata[:len(data)] = data
@@ -647,9 +647,12 @@ class SoundPlugin(Plugin):
 
         for i, event in completed_callback_events.items():
             event.wait()
-            del self.completed_callback_events[i]
+            if i in self.completed_callback_events:
-            del self.active_streams[i]
+                del self.completed_callback_events[i]
-            del self.stream_mixes[i]
+            if i in self.active_streams:
+                del self.active_streams[i]
+            if i in self.stream_mixes:
+                del self.stream_mixes[i]
 
         self.logger.info('Playback stopped on streams [{}]'.format(
             ', '.join([str(stream) for stream in
@@ -730,10 +733,6 @@ class SoundPlugin(Plugin):
         :type frequency: float
         """
 
-        if sound_index is None and midi_note is None and frequency is None:
-            raise RuntimeError('Please specify either a sound index, ' +
-                               'midi_note or frequency to release')
-
         mixes = {
             i: mix for i, mix in self.stream_mixes.items()
         } if stream_index is None else {

platypush/plugins/sound/core.py

@@ -131,7 +131,8 @@ class Sound(object):
         :param samplerate: Audio sample rate. Default: 44100 Hz
         :type samplerate: int
 
-        :returns: A numpy.ndarray[n,1] with the raw float values
+        :returns: A ``numpy.ndarray[(t_end-t_start)*samplerate, 1]``
+            with the raw float values
         """
 
         import numpy as np
@@ -156,6 +157,45 @@ class Sound(object):
         return self.gain * wave
 
 
+    def fft(self, t_start=0., t_end=0., samplerate=_DEFAULT_SAMPLERATE,
+            freq_range=None, freq_buckets=None):
+        """
+        Get the Fourier transform associated to a time-bounded sample of this
+            sound
+
+        :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 samplerate: Audio sample rate. Default: 44100 Hz
+        :type samplerate: int
+
+        :param freq_range: FFT frequency range. Default: ``(0, samplerate/2)``
+            (see `Nyquist-Shannon sampling theorem <https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem>`_)
+        :type freq_range: list or tuple with 2 int elements (range)
+
+        :param freq_buckets: Number of buckets to subdivide the frequency range.
+            Default: None
+        :type freq_buckets: int
+
+        :returns: A numpy.ndarray[freq_range,1] with the raw float values
+        """
+
+        import numpy as np
+
+        if not freq_range:
+            freq_range = (0, int(samplerate/2))
+
+        wave = self.get_wave(t_start=t_start, t_end=t_end, samplerate=samplerate)
+        fft = np.fft.fft(wave.reshape(len(wave)))[freq_range[0]:freq_range[1]]
+
+        if freq_buckets is not None:
+            fft = np.histogram(fft, bins=freq_buckets)
+
+        return fft
+
     def __iter__(self):
         for attr in ['midi_note', 'frequency', 'gain', 'duration']:
             yield (attr, getattr(self, attr))
@@ -278,6 +318,46 @@ class Mix(object):
         return wave
 
 
+    def fft(self, t_start=0., t_end=0., samplerate=Sound._DEFAULT_SAMPLERATE,
+            freq_range=None, freq_buckets=None):
+        """
+        Get the Fourier transform associated to a time-bounded sample of 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 samplerate: Audio sample rate. Default: 44100 Hz
+        :type samplerate: int
+
+        :param freq_range: FFT frequency range. Default: ``(0, samplerate/2)``
+            (see `Nyquist-Shannon sampling theorem <https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem>`_)
+        :type freq_range: list or tuple with 2 int elements (range)
+
+        :param freq_buckets: Number of buckets to subdivide the frequency range.
+            Default: None
+        :type freq_buckets: int
+
+        :returns: A numpy.ndarray[freq_range,1] with the raw float values
+        """
+
+        import numpy as np
+
+        if not freq_range:
+            freq_range = (0, int(samplerate/2))
+
+        wave = self.get_wave(t_start=t_start, t_end=t_end, samplerate=samplerate)
+        fft = np.fft.fft(wave.reshape(len(wave)))[freq_range[0]:freq_range[1]]
+
+        if freq_buckets is not None:
+            fft = np.histogram(fft, bins=freq_buckets)
+
+        return fft
+
+
     def duration(self):
         """
         :returns: The duration of the mix in seconds as duration of its longest