diff --git a/gst/rtsp-server/rtsp-media.c b/gst/rtsp-server/rtsp-media.c
index 6b81e254e5dd1bdcb465c02b636869dde684d2cb..a46464222ce410f42737dfd97a39d6ceb039d428 100644
--- a/gst/rtsp-server/rtsp-media.c
+++ b/gst/rtsp-server/rtsp-media.c
@@ -1083,7 +1083,7 @@ gst_rtsp_media_get_buffer_size (GstRTSPMedia * media)
 
   priv = media->priv;
 
-  g_mutex_unlock (&priv->lock);
+  g_mutex_lock (&priv->lock);
   res = priv->buffer_size;
   g_mutex_unlock (&priv->lock);