diff --git a/libavformat/mov.c b/libavformat/mov.c
index d6aeae048f..2f79aa3727 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -10296,10 +10296,11 @@ static int mov_parse_tiles(AVFormatContext *s)
 
             for (k = 0; k < mov->nb_heif_item; k++) {
                 HEIFItem *item = mov->heif_item[k];
-                AVStream *st = item->st;
+                AVStream *st;
 
                 if (!item || item->item_id != tile_id)
                     continue;
+                st = item->st;
                 if (!st) {
                     av_log(s, AV_LOG_WARNING, "HEIF item id %d from grid id %d doesn't "
                                               "reference a stream\n",