We are conducting R&D on content multiplexing technologies on the basis of MPEG Media Transport (MMT) technology, which was adopted for the advanced satellite broadcasting for 4K/8K, with the aim of realizing services that are equally available irrespective of the channel, whether broadcasting or broadband networks, and creating new viewing experiences. Our work included research on a multiplexing transmission method for next-generation terrestrial TV broadcasting, demonstration experiments of IP multicast delivery and a delivery technology for 3D content.

■Multiplexing transmission method for next-generation terrestrial TV broadcasting

  Aiming for next-generation terrestrial TV broadcasting, we previously researched a multiplexing scheme for IP packets that conforms to the channel coding system for terrestrial broadcasting and an IP transmission system used over studio to transmitter links (STLs) to enable a single-frequency network (SFN) and prototyped a remux. In FY 2018, we conducted verification experiments using the remux and confirmed the effectiveness of the schemes we studied. The experiments were conducted using the Higashiyama and Nabeta stations, which we launched in Nagoya as new experimental transmission stations for next-generation terrestrial broadcasting. We connected a remux (in Higashiyama) and a modulator for next-generation terrestrial broadcasting (in Nabeta) over a commercial IP network and transmitted transmission signals for next-generation terrestrial broadcasting. The results demonstrated that an SFN can be built by using signaling information in the transmission signals for synchronization control. To improve reliability and operability for practical use of the remux, we also developed a network redundancy device that improves the reliability of transmission over STLs by using IP networks of multiple network service providers simultaneously and a network status monitoring device for improving the operability.
  Part of this research was conducted as a government-commissioned project from the Ministry of Internal Affairs and Communications titled "R&D on Advanced Technologies for Terrestrial Television Broadcasting."

■Demonstration experiment on IP multicast delivery

  To promote 4K/8K content delivery, we verified MMT-based IP multicast delivery technology that could be used for the IP retransmission of broadcasting in closed networks of cable TV stations and other service providers and for the IP delivery of the relevant content linked with broadcasting. In the verification experiments, we up-linked multiple channels of live video from a stadium in Fukui Prefecture to an internet exchange (IX) service provider in Tokyo and delivered the content to nine cable TV service providers across the country simultaneously through IX equipment. The results of the experiments showed that packets observed in the reception point had no problem with quantitative transmission quality such as jitter, demonstrating the feasibility of simultaneous multichannel delivery of 4K/8K content on a nationwide scale using existing IX connection lines owned by cable TV service providers.

■Delivery technology for 3D content

  We began research on a delivery technology for 3D content in anticipation of future implementation of Diverse Vision. We developed a system that transmits the motion data of objects in a 3D space in real time over a broadband network using the same time base as that for video and sound of TV broadcasting and allows synchronized viewing of the objects on the screen of a tablet device using Augmented Reality (AR)(1)(2). We exhibited interactive content "Domo's Slapstick Race," in which NHK character Domo and his friends compete in a race at a fantasy stadium, at the NHK STRL Open House 2018. This exhibit can present free-viewpoint images of the race using AR on a tablet device in synchronization with an overview of the race at the stadium displayed on the TV screen. Feeling like a cameraperson, each viewer can enjoy a new viewing experience offered by broadcasting and AR, in which they can take a peek at a place not displayed on the TV screen or follow their favorite character on their tablet device. We exhibited this system at various local events such as "Okhotsk Mirai Festival" held in July in Kitami City, Hokkaido, "Saga Saiko Festival" in October in Saga City, Saga, and "Seto City Digital Festival" in November in Seto City, Aichi.

 

[References]
(1)	Y. Kawamura and K. Otsuki: "3D Free-viewpoint Augmented Reality on a Second Display Synchronized with a Broadcast Program," Proceedings of ICCIP (2018)
(2)	Y. Kawamura and K. Otsuki: "Real-time Distribution for Free-Viewpoint Augmented Reality Content Synchronized with a Broadcast Program," ITE Technical Report, vol.42, no.41, BCT2018-93, 2018, p.49-54 (2018) (in Japanese)