One of the advantages of broadcasting is the ability to deliver high-quality programs to many viewers simultaneously. With the rapid progress of broadband infrastructure in recent years, it has become possible to distribute videos and sounds on the Internet.
 To further enrich broadcasting, a suitable scheme is necessary to distribute video and sound simultaneously and reliably on broadband infrastructures in the same way as broadcasting, instead of using them just as complementary infrastructure such as NHK's Internet radio service "Radiru-Radiru". We are studying MMT (MPEG Media Transport) multiplexing scheme and its practical applications to distribute video, sound and data over multiple channels to viewers.
 The current satellite/terrestrial digital broadcasting uses MPEG-2 TS (Transport Stream) multiplexing. This scheme, standardized in 1994, has difficulties in extensibility; for example, it cannot transmit a file larger than 256 Mbyte. It also needs to multiplex video, sound and data that constitute a program and its service information into one stream for transmission, so it is difficult to be used for a service linked with multiple channels, i.e. broadband networks.
 MMT has three major functions: synchronization, multiplexing and the reliability of transmission.
  "Synchronization" is a function to present a program’s video, sound and data at the right timing. As MMT adds time information in units of videos and sounds referring to the world time clock, it can synchronize the signals passing through different channels on the receiver side. For example, it can treat a video and main sound transmitted by broadcasting and a sub sound (e.g. multi-language interpretation and commentary) transmitted by broadband as a single program. It thus allows users to present a program according to their preference without caring about the difference between broadcasting and broadband.
 It also enables viewers to specify the position of presenting video on the TV screen or display the related video and data on the second display screen such as a tablet. "Multiplexing" is a function to put together various information that constitutes a program. By packetizing video, sound and data into MMTP packets, it enables efficient transmission through various channels of broadcasting and broadband. Quality degradation such as a transmission error, packet loss and reorder may occur in broadband. To prevent them from affecting viewers’ program viewing, MMT has a mechanism to detect and recover a packet if it is not properly received. With this function, it achieves "the reliability of transmission" like broadcasting, even when the transmission quality is largely influenced by a mixture of wired and wireless transmission.
 There are growing expectations for a high-quality and high value-added broadcasting service that proactively uses broadband.
【 Displaying information by convergence of broadcasting and communications using MMT 】

【 MMT's main features 】

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