diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 9218689239..fa2844d2cf 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -581,7 +581,8 @@ int av_packet_ref(AVPacket *dst, const AVPacket *src)
         ret = packet_alloc(&dst->buf, src->size);
         if (ret < 0)
             goto fail;
-        memcpy(dst->buf->data, src->data, src->size);
+        if (src->size)
+            memcpy(dst->buf->data, src->data, src->size);
 
         dst->data = dst->buf->data;
     } else {