diff --git a/libavcodec/vp9.c b/libavcodec/vp9.c
index 1ebf5ac18b..7957cbeab9 100644
--- a/libavcodec/vp9.c
+++ b/libavcodec/vp9.c
@@ -255,8 +255,10 @@ static int update_size(AVCodecContext *avctx, int w, int h)
         *fmtp = AV_PIX_FMT_NONE;
 
         ret = ff_get_format(avctx, pix_fmts);
-        if (ret < 0)
+        if (ret < 0) {
+            ff_set_dimensions(avctx, s->w, s->h);
             return ret;
+        }
 
         avctx->pix_fmt = ret;
         s->gf_fmt  = s->pix_fmt;