fix: cap playback duration to actual audio length

sync_audio_test.py

@@ -273,10 +273,11 @@ class SyncWindow(QtWidgets.QMainWindow):
 
         ctr2.addWidget(QtWidgets.QLabel("Duration:"))
         self.play_dur = QtWidgets.QDoubleSpinBox()
-        self.play_dur.setRange(0.1, 30.0)
+        max_dur = min(self.duration, len(self.a_orig) / self.sr)
+        self.play_dur.setRange(0.1, max(max_dur, 0.1))
         self.play_dur.setDecimals(1)
         self.play_dur.setSingleStep(0.5)
-        self.play_dur.setValue(2.0)
+        self.play_dur.setValue(min(2.0, max_dur))
         self.play_dur.setSuffix("s")
         self.play_dur.setMaximumWidth(80)
         ctr2.addWidget(self.play_dur)