diff --git a/libavcodec/videotoolbox_vp9.c b/libavcodec/videotoolbox_vp9.c
index f5489854e3..d870ea5d0f 100644
--- a/libavcodec/videotoolbox_vp9.c
+++ b/libavcodec/videotoolbox_vp9.c
@@ -70,12 +70,12 @@ CFDataRef ff_videotoolbox_vpcc_extradata_create(AVCodecContext *avctx)
     uint8_t *vt_extradata;
     int subsampling = get_vpx_chroma_subsampling(avctx->sw_pix_fmt, avctx->chroma_sample_location);
 
-    vt_extradata_size = 1 + 3 + 6 + 2;
-    vt_extradata = av_malloc(vt_extradata_size);
-
     if (subsampling < 0)
         return NULL;
 
+    vt_extradata_size = 1 + 3 + 6 + 2;
+    vt_extradata = av_malloc(vt_extradata_size);
+
     if (!vt_extradata)
         return NULL;