diff --git a/libavcodec/h2645_parse.c b/libavcodec/h2645_parse.c
index 307e8643e6..ef6a6b4b4f 100644
--- a/libavcodec/h2645_parse.c
+++ b/libavcodec/h2645_parse.c
@@ -461,8 +461,7 @@ int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
                 return AVERROR(ENOMEM);
 
             pkt->nals = tmp;
-            memset(pkt->nals + pkt->nals_allocated, 0,
-                   (new_size - pkt->nals_allocated) * sizeof(*pkt->nals));
+            memset(pkt->nals + pkt->nals_allocated, 0, sizeof(*pkt->nals));
 
             nal = &pkt->nals[pkt->nb_nals];
             nal->skipped_bytes_pos_size = 1024; // initial buffer size