diff --git a/rtcllm/vad.py b/rtcllm/vad.py
index 61269c4..f23afec 100644
--- a/rtcllm/vad.py
+++ b/rtcllm/vad.py
@@ -10,6 +10,7 @@ import webrtcvad
 import wave
 from scipy.io.wavfile import write
 import numpy as np
+import av
 from av import AudioLayout, AudioResampler, AudioFrame, AudioFormat
 
 class AudioTrackVad(MediaStreamTrack):