Digital terrestrial TV broadcasting will start service in Japan from the year 2003 and extensive plans are being made to provide fully equipped broadcast systems. In this service, the available bit-rate for the secondary distribution of HDTV is limited from 11 to 15Mbps, and an effective high compression encoding technologies are required to maintain a satisfactory picture quality at such a low bit-rate. In this paper, HDTV is assumed to be a typical digital television application and an optimal rate control is introduced as an effective technology to achieve higher coding gain. First, the problems caused by the conventional scheme when applied at such low bit-rates are shown, and the modified rate control scheme is proposed and evaluated for the picture layer and the macroblock layer, respectively.
A higher efficient HDTV coding technique is desired to enrich digital broadcasting services. In the MPEG-2 video coding, which is commonly used for digital broadcasting, a motion vector rate is almost constant and not related to the coding bit rate. Therefore, at a lower bit rate, the motion vector rate is generally high and the quantiser scale becomes large to reduce the DCT coefficient rate. This is the major factor that causes remarkable picture degradation by HDTV low bit rate coding. To improve picture quality at the lower bit rate, the motion vector rate should be suppressed. This paper describes an improvement method of picture quality by selecting the coding mode and the motion vectors so that give the minimum amount of the transmitted bits in a macroblock.
This paper presents a prototype of an authoring tool for the "information navrgation-type advanced broadcasting service" - a novel data broadcasting service the data of which are linked to moving objects on a TV screen. The major objectives of the tool are to input temporal transition of each object's position and size, to generate binary tables of the region information, and to make object-related BML templates. Users can take advantage of automatic extraction/tracking plug-ins when inputting region information through spatio-temporal editing GUIs. The binary tables and the BML templates (with ECMAScripts) generated by the tool are based upon the data broadcasting standard ARIB STD-B24.
The popularity of the World Wide Web has been enormously increasing in recent years. This enables broadcasters to demonstrate the new type of potential utilizing various digital content in broadcast programs. A digital watermarking has been of interest to numerous broadcasters to protect ownership rights of the digital content. In recent years, we at NHK Tokyo have been challenging toward studying a suitable digital watermarking technology of thedigital content production for our World Wide Web services. In this paper, we outline our current studies based on a number of experiments.
The EMC World Cup Golf Tournament was held at the Gotenba Golf Course of the Taiheiyo Club in Shizuoka, Japan from November 15th to 18th, 2001. As a host broadcaster, NHK produced the international signal of the event in HD/SD format, distributed it to many countries worldwide and broadcast it live through terrestrial TV, satellite TV, and HDTV. NHK also initiated data broadcasting as a new service that provides real-time information about the players. This paper describes technical features and problems encountered in producing the large-scale HDTV Iive coverage of the event.
BS Asahi has started broadcasting some programs in 5.1-channel audio since September 2001. However, many viewers still listen to it with two-channel stereo facilities that downmixes the 5.1-channel material. In making programs, one has to take those viewers into consideration. In addition, there is moment of silence when changing the audio coding. We will report what we have examined and found out about the 5.1-channel audio broadcast.
We are studying an intelligent robot camera system as a new support system for program-production. Our objective is to develop a robot camera system that not only automatically shoots performers and objects but also works as if it were broadcasting cameramen. We have analyzed the shooting techniques of broadcasting cameramen as a first step towards modeling these techniques. We have recently developed a network-connected robot camera system for talk shows which two performers appear on. This paper gives a detailed description of the system and the experiments we have carried out with it.