First work on signal generator

lasp/lasp_siggen.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python3.6
+# -*- coding: utf-8 -*-
+"""
+Description: Read data from image stream and record sound at the same time
+"""
+from .lasp_atomic import Atomic
+from threading import Thread, Condition, Lock
+from .lasp_avstream import AvType, AvStream
+import numpy as np
+
+class SignalGenerator:
+    """
+    Base class for all signal generator types
+    """
+
+    def __init__(self, stream):
+
+        if not (stream.avtype == AvType.audio_output or (stream.avtype ==
+                                                        AvType.audio_input and
+                                                        stream.duplex_mode)):
+            raise RuntimeError('Invalid stream type. Does not support audio'
+                               'output')
+
+        self.stream = stream
+        self._samplerate = stream.samplerate
+        stream.addCallback(self.streamCallback, AvType.audio_output)
+
+    def stop(self):
+        """
+        Stop generating the signal
+        """
+        self.stream.removeCallback(self.streamCallback, AvType.audio_output)
+
+    def streamCallback(self, indata, outdata, blockctr):
+        """
+        Callback from AvStream.
+        """
+        signal = self.getSignal(blockctr*outdata.shape[0], outdata.shape[0])
+        dtype = self.stream.numpy_dtype
+
+        if dtype == np.float32 or dtype == np.float64:
+            fac = 1
+        else:
+            bitdepth_fixed = self.stream.sampwidth*8
+            fac = 2**(bitdepth_fixed-1)
+
+        outdata[:, :] = (fac*signal).astype(dtype)[:, np.newaxis]
+
+
+class SineGenerator(SignalGenerator):
+    def __init__(self, stream, freq):
+        self._omg = 2*freq*np.pi
+        super().__init__(stream)
+
+    def getSignal(self, startidx, frames):
+        samplerate = self._samplerate
+        streamtime = startidx/samplerate
+        t = np.linspace(streamtime, streamtime + frames/samplerate, frames)
+
+        return 0.1*np.sin(self._omg*t)
+
+
+class NoiseGenerator(SignalGenerator):
+    def __init__(self, stream, noisetype): 
+        super().__init__(stream)
+    
+    def getSignal(self, startidx, frames):
+        return 0.1*np.random.randn(frames)
+
+class NoiseType:
+    white = (0, 'White noise', )
+    pink = (1, 'Pink noise')
+    types = (white, pink)
+
+    @staticmethod
+    def fillComboBox(combo):
+        for type_ in NoiseType.types:
+            combo.addItem(type_[1])
+
+    @staticmethod
+    def getCurrent(cb):
+        return NoiseType.types[cb.currentIndex()]
+
+
+
+