Advanced Terrestrial Broadcasting Technology

Research into transmission technology for ultra-high-definition television terrestrial broadcasting

VVC (Versatile Video Coding)

VVC is a new video coding method that has been standardized internationally through the efforts of companies and research institutions from around the world. The first edition was finalized in July 2020. The need for video compression technology has been increasing with the spread of video streaming services, e.g., streaming over 5G networks and services in the IoT that involve video communications. VVC is a general-purpose coding method that also supports coding of HDR (High Dynamic Range) video and omnidirectional (360°) video in addition to conventional SDR (Standard Dynamic Range) video.
Compared with the HEVC (High Efficiency Video Coding) method that is used in satellite broadcasting for ultra-high-definition television (UHDTV) service, VVC reduces the transmission rate by around 40% for the same coding quality, as shown in the table below. Furthermore, it provides higher image quality for the same transmission rate, as shown in the figure below.

Table 1 VVC encoding performance improvement* and computational complexity compared to HEVC
Video resolution Encoding performance improvement
4K (2160p) -44.7%
2K (1080p) -41.7%
Encoder computational complexity Around 8.0 times
Decoder computational complexity Around 1.6 times
Figure 1 Comparison of image degradation between HEVC and VVC

*Indicator showing the reduction in transmission rate compared to a reference method to reproduce the same quality. Larger negative values indicate higher performance.

Real-time audio encoder/decoder using the MPEG-H 3D Audio BL profile

MPEG-H 3D Audio is an audio coding method that supports object-based sound systems*1. It makes it possible for the viewer to customize their viewing experience by, for example, changing the volume of narration or switching to a preferred language. In our investigation of advanced terrestrial broadcasting, we employed the BL profile, which is the latest profile*2 that has a lighter implementation load compared with the LC profile. We developed a world-first real-time audio encoder/decoder at level 4 in supporting 22.2 multichannel (22.2 ch) sound and have been investigating its practicability.

Figure 2 How the object-based sound system works
Figure 3 The developed real-time audio encoder (left) and real-time audio decoder (right)
Table 2 Specifications of the developed real-time audio encoder/decoder
Item Specifications
I/O interface MADI (AES10)
No. of audio inputs No. of audio inputs Max. 56 ch (Example: 22.2 ch background sound + 12 languages)
No. of audio outputs Max. 24 ch (Example: 22.2 ch sound)
Input audio metadata Input audio metadata Serial representation of the Audio Definition Model*3
Multiplexed streaming format MMT/IP
Audio formats that can be rendered Mono, stereo, 5.1 ch, 7.1 ch, 22.2 ch, 5.1.2 ch, 5.1.4 ch, 7.1.4 ch*4
Bit rate 22.2 ch sound can be compressed at 512 kbit/s*5
  1. A method where the individual audio signals (audio objects) are transmitted under the control of audio metadata and are reproduced by a renderer (a device that processes the audio signals in accordance with the audio metadata and viewing environment information).
  2. A subset of encoding tools
  3. Complies with Rec. ITU-R BS.2125-0.
  4. Each digit of 5.1.2, 5.1.4, and 7.1.4 corresponds to the number of channels in the middle layer, LFE, and top layer.
  5. Meets broadcast quality specified in Rec ITU-R BS.1548-7.