diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index aba934c33d..2f10998bd3 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -2061,7 +2061,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
     }
 
     if (!(trk->entry % MOV_INDEX_CLUSTER_SIZE)) {
-        trk->cluster = av_realloc(trk->cluster, (trk->entry + MOV_INDEX_CLUSTER_SIZE) * sizeof(*trk->cluster));
+        trk->cluster = av_realloc_f(trk->cluster, sizeof(*trk->cluster), (trk->entry + MOV_INDEX_CLUSTER_SIZE));
         if (!trk->cluster)
             return -1;
     }