diff --git a/encoder/audio.py b/encoder/audio.py
index 799aa83..5c087ee 100644
--- a/encoder/audio.py
+++ b/encoder/audio.py
@@ -56,8 +56,8 @@ def wav_to_mel_spectrogram(wav):
     Note: this not a log-mel spectrogram.
     """
     frames = librosa.feature.melspectrogram(
-        wav,
-        sampling_rate,
+        y=wav,
+        sr=sampling_rate,
         n_fft=int(sampling_rate * mel_window_length / 1000),
         hop_length=int(sampling_rate * mel_window_step / 1000),
         n_mels=mel_n_channels