add stereo input compatability

app.py

@@ -210,6 +210,8 @@ def container_generate(model_selection, task_selection, audio, singer_id, t0):
     if audio is None:
         return None, None
     sr, audio = audio
+    if len(audio.shape) == 2:
+        audio = np.mean(audio, axis=1)              # convert stereo to mono
     if len(audio) < 12*sr and task_selection == 'Melodic Reinterpretation':    
         # make sure the audio is at least 12 s long
         audio = np.pad(audio, (0, 12*sr - len(audio)), mode='constant')