Update app.py

app.py

@@ -6,6 +6,7 @@ def convert_6ch_wav_to_stereo(input_file_path, output_file_path):
     sound = AudioSegment.from_file(input_file_path, format="wav")
     if sound.channels != 6:
         sound.export(output_file_path, format="wav")
+        return 
     front_left = sound.split_to_mono()[0]
     front_right = sound.split_to_mono()[1]
     center = sound.split_to_mono()[2]