Update app.py

app.py

@@ -98,6 +98,9 @@ with gr.Blocks(title="AST Model") as demo:
     def wrapper(audio_path):
         waveform, probs, id2label = predict_audio(audio_path)
 
+        if waveform is None:
+            return None, None, None
+                         
         mel_spec = librosa.feature.melspectrogram(
                 y = waveform, sr = AST_SR, n_mels = 128
         )