diff --git a/libavcodec/ulti.c b/libavcodec/ulti.c
index e6f4374981..9e4c088b10 100644
--- a/libavcodec/ulti.c
+++ b/libavcodec/ulti.c
@@ -50,6 +50,8 @@ static av_cold int ulti_decode_init(AVCodecContext *avctx)
     s->width = avctx->width;
     s->height = avctx->height;
     s->blocks = (s->width / 8) * (s->height / 8);
+    if (s->blocks == 0)
+        return AVERROR_INVALIDDATA;
     avctx->pix_fmt = AV_PIX_FMT_YUV410P;
     s->ulti_codebook = ulti_codebook;