Advanced Terrestrial Broadcasting Technology

We investigated how to combine broadcast and broadband transmissions and created a prototype transmission system based on the results of our investigation. After that, we investigated the capabilities of the reception system and verified its practicality on a PC. The home gateway that was tested as the receiver system is introduced on the "New Terrestrial Broadcasting Service Using Technology that Merges Broadcasting with Network Communication" page.

For the advanced terrestrial broadcasting, we are developing a software-based transmission distribution system that can be implemented as a cloud service. This system uses software to implement various transmission functions that have conventionally been made up of dedicated hardware units and has a functionality to handle multiple transmission channels (terrestrial broadcasting, managed network, and internet) in combination. As a result, it is possible to offer more advanced services that combine broadcast content and broadband content.

We have already investigated, for example, the transmission scheduler function for automatically switching resources based on the configured program compilation information, a re-multiplexing function for transmitting programs to broadcast stations, and a distribution function for providing auxiliary information during disasters and for providing information to associate broadcast and broadband content. Furthermore, an MMT-SI (Service Information) signal was implemented to enable the system to support the CMAF/MMT format.

In order to smoothly combine broadcast and broadband video streams, we aim to use standardized media formats. We have investigated the use of CMAF (Common Media Application Format) in the advanced terrestrial broadcasting service. CMAF is increasingly used as the media format of network communication OTT (over the top) services. We have also investigated CMAF over MMT (MPEG Media Transport). To apply CMAF to our service, we investigated the use of ISOBMFF (ISO Base Media File Format) metadata, which is not used in the current 4K/8K satellite broadcasting. This format can create and send media data in chunks whose structure is compliant with CMAF. Media data can be transmitted with low latency; in particular, CMAF avoids the latency of a GOP (group of pictures) duration, which is around 0.5 seconds. It is also used in broadcast MMT.