diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index b6b4109a2c..3469647277 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -225,8 +225,10 @@ int av_copy_packet_side_data(AVPacket *pkt, AVPacket *src)
         int i;
         DUP_DATA(pkt->side_data, src->side_data,
                 src->side_data_elems * sizeof(*src->side_data), 0, ALLOC_MALLOC);
-        memset(pkt->side_data, 0,
-                src->side_data_elems * sizeof(*src->side_data));
+        if (src != pkt) {
+            memset(pkt->side_data, 0,
+                   src->side_data_elems * sizeof(*src->side_data));
+        }
         for (i = 0; i < src->side_data_elems; i++) {
             DUP_DATA(pkt->side_data[i].data, src->side_data[i].data,
                     src->side_data[i].size, 1, ALLOC_MALLOC);