This paper studies the video bit-rate required for 8K 119.88 Hz (120 Hz) high efficiency video coding (HEVC)/H.265 temporal scalable coding that can partially decode 59.94 Hz (60 Hz) video frames from compressed 120 Hz bit-streams. We compress 8K 120 Hz test sequences using software that emulates our developing HEVC/H.265 encoder and conduct two types of subjective evaluation experiments to investigate the appropriate bit-rate for both 8K 120 and 60 Hz videos for broadcasting purpose. From the results of the experiments, we conclude that the required video bit-rate for 8K 120 Hz temporal scalable coding is estimated to be between 85 and 110 Mbps, which is equivalent to the practical bit-rate for 8K 60 Hz videos, and the appropriate bitrate allocation for the 8K 60 Hz video in 8K 120 Hz temporal scalable video coding at 85 Mbps is presumed to be ~80 Mbps.

In this study, we verify a pair comparison method in which videos being evaluated can be repeated by the evaluators as many times as desired. We use the method to conduct a subjective evaluation of 8K 119.88 Hz (120 Hz) and 59.94 Hz (60 Hz) videos that were compressed using software that emulates an 8K 120 Hz encoder. The experimental results confirm that (1) this method can detect small differences between video qualities, (2) all video pairs must be evaluated because the order effect is not negligible, and (3) the appropriate number of repeats is between four and nine.

To help pave the way for Super Hi-Vision (SHV) broadcasting, we have developed a new codec system that can encode and decode SHV signals in real time. This is the third generation of SHV real-time hardware codec. This efficient compression system maintains high picture quality by using eight 1080/60p (60 frames/s) encoding units and a video format converter with signal compensation processing that takes the properties of the Dual Green format of SHV into account. The video format converter divides an SHV image spatially into eight 1920 × 1080 portions, each of which is fed to the encoding unit. In the previous SHV codec, the SHV image was divided into 16 portions (spatially eight and temporally two) and 16 1080/30p encoding units were used. Compared with the previous system, the new codec achieves a 50% bitrate saving and downsizes the codec by almost half. Furthermore, several new technologies were developed and installed in the codec. We conducted the world's first SHV international transmission over an advanced Internet connection using the codec at a TS rate of 260 Mb/s. The received picture quality was good enough to show any kind of SHV content on a large screen.

We propose a novel compression technique on signs of DCT coefficients. The proposed technique utilizes a high correlation among pixels at boundaries of a current block and those of neighboring blocks and estimates the original signs. It encodes the difference between the original coefficient signs and the estimated signs. We also propose a speeding up technique for the estimation, utilizing concepts of Gray code and transform matrix decomposition. Compared to JM16.2, the proposed technique reduces 10% bitrate in sign bits of DCT coefficients and achieves 1% BD-bitrate reduction in total bitstream. With the speeding up technique, complexities increase only 8% and 5% on an encoder and a decoder side, respectively.

We propose a derivation scheme of a motion vector for interlace format. The adjustment of the vertical component of a chroma MV for 4:2:0 format and the adjustment of the vertical component of a luma prediction MV are introduced in order to remove inconsistency between the current derivation process of motion vector predictor and the nature of interlace format in HM4.0. The proposed scheme achieves up to 1.0dB PSNR improvements in chroma components and up to 3.4% bit-rate reduction.