diff --git a/vggish.py b/vggish.py
index ab8d014..9b8a054 100644
--- a/vggish.py
+++ b/vggish.py
@@ -61,10 +61,8 @@ class Vggish(NNOperator):
     def preprocess(self, frames: List[AudioFrame]):
         sr = frames[0].sample_rate
         audio = numpy.hstack(frames)
-        if audio.dtype == numpy.int32:
-            audio = audio / 2147483648.0
-        elif audio.dtype == numpy.int16:
-            audio = audio / 32768.0
+        ii = numpy.iinfo(audio.dtype)
+        audio = 2 * audio / (ii.max - ii.min + 1)
         try:
             audio = audio.transpose()
             audio_tensors = vggish_input.waveform_to_examples(audio, sr, return_tensor=True)