diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 66c5375f41..8a803e7022 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1111,6 +1111,7 @@ static int jpeg2000_decode_packets_po_iteration(Jpeg2000DecoderContext *s, Jpeg2
                 step_x = FFMIN(step_x, rlevel->log2_prec_width  + reducedresno);
                 step_y = FFMIN(step_y, rlevel->log2_prec_height + reducedresno);
             }
+            av_assert0(step_x < 32 && step_y < 32);
             step_x = 1<<step_x;
             step_y = 1<<step_y;