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Minato-ku, Japan

Shigenobu M.,Japan Cable Laboratories | Noda T.,Japan Cable Laboratories | Toyokawa H.,Japan Cable Laboratories
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers | Year: 2013

In recent years, Wi-Fi has been attracting attention as a low cost, safe and convenient access technology. Wi-Fi in the United States has been organized as a part of the business strategy of cable operators. In addition, the form of service has changed from wired to wireless, from indoor to outdoor. The AP built-in cable modem has become very popular in the market. Evaluations to realize cable Wi-Fi service have been conducted and cable Wi-Fi services by some cable operators get started in Japan. To provide services such as Internet access with public wireless LAN cable operators, Japan Cable Laboratories completed the technical specifications for cable Wi-Fi with the aim of a unified, common standard in the industry. An evaluation was conducted through field testing to verify subscriber authentication protocol, throughput and signal propagation. We developed operational guidelines relating to the maintenance and operation of Wi-Fi equipment. Source


Yanagihara H.,KDDI R and D Laboratories Inc. | Naito S.,KDDI R and D Laboratories Inc. | Miyaji S.,KDDI | Sakazawa S.,KDDI R and D Laboratories Inc. | And 3 more authors.
ITE Transactions on Media Technology and Applications | Year: 2013

For cable TV services which have grown and expanded over the last 50 or more years, we provide a forecast of their future applications, as well as cutting-edge technology. In particular, in addition to the benefits of fundamental multi-channel broadcasting and two-way communications technologies, we outline a number of possible services such as 8K video, 3D HDTV, a free-viewpoint TV, server-client based advanced applications, and multiple device associations between STB and other devices. Copyright © 2013 by ITE Transactions on Media Technology and Applications (MTA). Source


Kato H.,KDDI R and D Laboratories Inc. | Naito S.,KDDI R and D Laboratories Inc. | Sakazawa S.,KDDI R and D Laboratories Inc. | Matsumoto S.,Japan Cable Laboratories
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers | Year: 2010

This paper proposes a novel coding method that reduces correlation of 4:4:4 chroma format in high-resolution images more than HDTV. The proposed method compensates for Intra prediction errors by applying the linear prediction to a certain Intra prediction error. The adaptive inter-channel prediction uses a coefficient that minimizes the MSE of the Intra prediction errors in each channel. The experimental results show that combining the Intra prediction and inter-channel prediction has better coding efficiency than the conventional method. Source


Takagi K.,KDDI | Sugimoto O.,KDDI R and D Laboratories Inc. | Naito S.,KDDI R and D Laboratories Inc. | Sakazawa S.,KDDI R and D Laboratories Inc. | And 2 more authors.
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers | Year: 2012

This paper proposes a rate reduction method for high frame-rate picture coding based on repeatedly displaying sharp and blurred pictures. Our contribution is a picture coding method utilizing a spatiotemporal frequency model derived from human perceptual limitation of high frame-rate pictures. This method removes the high frequency parts of residual coefficients based on the spatiotemporal properties derived from local image data. Experimental results show that the proposed method achieves an average of 15% bit savings over the conventional MPEG-4 AVC/H.264 coding method without subjective degradation. Source


Yoshino T.,KDDI R and D Laboratories Inc. | Naito S.,KDDI R and D Laboratories Inc. | Shigeyuki,KDDI R and D Laboratories Inc. | Sakazawa,KDDI R and D Laboratories Inc. | Matsumoto S.,Japan Cable Laboratories
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers | Year: 2010

Ultra-high resolution video is expected to be one of the next-generation high quality video formats. Current video coding technology H.264 achieves the maximum amount of coding efficiency from among the existing coding standards. However, even H.264 is not sufficient enough for ultra-high resolution video distribution service due to a lack of coding efficiency. Therefore, an enhanced video coding technology is strongly required to improve the coding efficiency. In the past works, several approaches for extending the macroblock (MB) size have been proposed, and these researches showed that extended MB size technology improved the coding efficiency, especially for high resolution video. However, a clear description of the performance improvement mechanism has yet to be presented. We analytically consider the coding characteristics of an extended MB size scheme for ultra-high resolution video in this paper. We clarified the coding gain mechanism of this technology based on a R-D characteristics analysis. Furthermore, we analytically confirmed that the extended MB size scheme was most effective at high-resolution and low-bitrate video coding. Finally, we conducted a coding experiment and found that the maximum bit reduction ratio reached approximately 15% using an optimal coding control for the extended MB size scheme. Source

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