diff --git a/torch_vggish.py b/torch_vggish.py
index 440e21b..deae00e 100644
--- a/torch_vggish.py
+++ b/torch_vggish.py
@@ -62,15 +62,12 @@ class Vggish(NNOperator):
         outs = features.to("cpu")
         return [AudioOutput(outs.detach().numpy())]
 
-    def preprocess(self, audio: Union[str, numpy.ndarray], sr: int = None):
-        if audio.dtype == numpy.int32:
-            samples = audio / 2147483648.0
-        elif audio.dtype == numpy.int16:
-            samples = audio / 32768.0
+    def preprocess(self, audio: numpy.ndarray, sr: int = None):
+        ii = numpy.iinfo(audio.dtype)
+        samples = 2 * audio / (ii.max - ii.min + 1)
         return vggish_input.waveform_to_examples(samples, sr, return_tensor=True)
 
 
-
 # if __name__ == '__main__':
 #     encoder = Vggish()
 #