diff --git a/wenet/dataset/processor.py b/wenet/dataset/processor.py
index 656e9ef8a..a0dea7973 100644
--- a/wenet/dataset/processor.py
+++ b/wenet/dataset/processor.py
@@ -108,9 +108,9 @@ def decode_wav(sample):
         with io.BytesIO(wav_file) as file_obj:
             waveform, sample_rate = torchaudio.load(file_obj)
             # del wav_file
-        del sample['wav']
-        sample['wav'] = waveform  # overwrite wav
-        sample['sample_rate'] = sample_rate
+    del sample['wav']
+    sample['wav'] = waveform  # overwrite wav
+    sample['sample_rate'] = sample_rate
     return sample