Predictions indicate that mobile video streams will dominate mobile traffic in the near future. Heterogeneous UDN is a promising technique for 5G mobile networks. This technique offers high access speeds for video watchers through the dense deployment of small cells. However, the backhaul of a UDN will become a bottleneck with the rapid increase in mobile video traffic. Additionally, the considerable video traffic generated from and to UDNs induces significant stress on the core network of a 5G network. Therefore, it is necessary to optimize the distribution of video content for 5G UDNs. Multicasting is considered to be a good communication method for distributing video content. This article examines a video multicast orchestration scheme based on SDN, named HCM, for 5G UDNs. To adapt well to a heterogeneous UDN environment in 5G networks and effectively save spectrum resources, HCM implements wireless multicast functionality based on a common unicast channel. HCM performs concurrent multicasting to clearly reduce the bandwidth consumption of a 5G network, particularly the backhaul, and further controls video traffic passed through the backhaul using a traffic-aware method. During the packet loss recovery of HCM, SDN-based elastic area multicast is used to more effectively retransmit recovered packets. The experimental results indicate that our proposed scheme can distribute video content with high effectiveness.