diff --git a/libmpcodecs/vf_harddup.c b/libmpcodecs/vf_harddup.c
index 88dd53125a..012cc22e99 100644
--- a/libmpcodecs/vf_harddup.c
+++ b/libmpcodecs/vf_harddup.c
@@ -50,18 +50,6 @@ static int control(struct vf_instance_s* vf, int request, void* data)
 	return vf_next_control(vf, request, data);
 }
 
-static int query_format(struct vf_instance_s* vf, unsigned int fmt)
-{
-	/* FIXME - figure out which other formats work */
-	switch (fmt) {
-	case IMGFMT_YV12:
-	case IMGFMT_IYUV:
-	case IMGFMT_I420:
-		return vf_next_query_format(vf, fmt);
-	}
-	return 0;
-}
-
 static void uninit(struct vf_instance_s* vf)
 {
 	free(vf->priv);