Add playing over left, right or both channels, fixes #10

hifiscan/app.py

@@ -54,10 +54,15 @@ class App(qt.QMainWindow):
                 if self.paused or lo >= hi or secs <= 0 or not ampl:
                     await asyncio.sleep(0.1)
                     continue
+                ch = self.channelsBox.currentIndex()
 
                 analyzer = hifi.Analyzer(lo, hi, secs, audio.rate, ampl,
                                          self.calibration, self.target)
-                audio.play(analyzer.chirp)
+                sound = analyzer.chirp
+                if ch:
+                    silence = np.zeros_like(sound)
+                    sound = [sound, silence] if ch == 1 else [silence, sound]
+                audio.play(sound)
                 async for recording in audio.record():
                     if self.paused:
                         audio.cancelPlay()
@@ -199,6 +204,8 @@ class App(qt.QMainWindow):
             value=1.0, step=0.1, bounds=[0.1, 30], suffix='s')
         self.ampl = pg.SpinBox(
             value=40, step=1, bounds=[0, 100], suffix='%')
+        self.channelsBox = qt.QComboBox()
+        self.channelsBox.addItems(['Stereo', 'Left', 'Right'])
         self.spectrumSmoothing = pg.SpinBox(
             value=15, step=1, bounds=[0, 30])
         self.spectrumSmoothing.sigValueChanging.connect(self.plot)
@@ -216,6 +223,7 @@ class App(qt.QMainWindow):
         hbox.addSpacing(32)
         hbox.addWidget(qt.QLabel('Amplitude: '))
         hbox.addWidget(self.ampl)
+        hbox.addWidget(self.channelsBox)
         hbox.addSpacing(32)
         hbox.addWidget(qt.QLabel('Smoothing: '))
         hbox.addWidget(self.spectrumSmoothing)

hifiscan/audio.py

@@ -5,6 +5,7 @@ from typing import AsyncIterator, Deque
 
 import eventkit as ev
 import numpy as np
+import numpy.typing as npt
 import sounddevice as sd
 
 
@@ -21,7 +22,7 @@ class Audio:
         self.recorded = ev.Event()
         self.playQ: Deque[PlayItem] = deque()
         self.stream = sd.Stream(
-            channels=1,
+            channels=2,
             callback=self._onStream)
         self.stream.start()
         self.rate = self.stream.samplerate
@@ -42,16 +43,19 @@ class Audio:
         idx = 0
         while self.playQ and idx < frames:
             playItem = self.playQ[0]
-            chunk = playItem.pop(frames - idx)
+            chunk = playItem.pop(frames - idx).T
-            idx2 = idx + chunk.size
+            idx2 = idx + len(chunk)
-            out_data[idx:idx2, 0] = chunk
+            out_data[idx:idx2, :] = chunk
             idx = idx2
             if not playItem.remaining():
                 self.playQ.popleft()
-        self.recorded.emit_threadsafe(in_data.copy())
+        self.recorded.emit_threadsafe(in_data.copy().T)
 
-    def play(self, sound: np.ndarray):
+    def play(self, sound: npt.ArrayLike):
         """Add a sound to the play queue."""
+        sound = np.asarray(sound)
+        if len(sound.shape) == 1:
+            sound = np.vstack([sound, sound])
         self.playQ.append(PlayItem(sound))
 
     def cancelPlay(self):
@@ -69,7 +73,8 @@ class Audio:
         """
         recording = array.array('f')
         return self.recorded.map(
-            recording.extend).constant(recording).aiter(skip_to_last=True)
+            lambda rec: recording.extend(0.5 * (rec[0] + rec[1]))) \
+            .constant(recording).aiter(skip_to_last=True)
 
 
 @dataclass
@@ -82,6 +87,6 @@ class PlayItem:
 
     def pop(self, num: int) -> np.ndarray:
         idx = self.index + min(num, self.remaining())
-        chunk = self.sound[self.index:idx]
+        chunk = self.sound[:, self.index:idx]
         self.index = idx
         return chunk