First anniversary of BS digital broadcasting BS digital broadcasting started on December 1, 2000, and with it, NHK now provides one HDTV service, two SDTV services, and several data services. BS digital broadcasting is now reaching more than one million digital receivers and 1.4 million analog-converted cable TV receivers in homes throughout Japan. This proliferation will accelerate as prices of digital receivers continue to fall. A significant increase in viewers is also expected for the upcoming World Cup soccer championships in Korea and Japan. Taking this transition as an opportunity to make its mark, NHK has begun to broadcast a variety of special HDTV programs and data services. From the technical viewpoint, these digital-technology-based services have been novel additions to the high-quality HDTV picture/sound and regular data service. They include: Bi-directional data broadcasting service Immediate reactions from the viewers can be easily acquired by making use of the bi-directional function of the data broadcasting service. Answers to questions posed on quiz programs or votes on on-air programs can be gathered in real time. In the quiz programs, even viewers rankings can easily be displayed on screen. EPG (Electronic Program Guide) The EPG function provides not only easy-to-select services from a series of on-screen menus but can also preset VCR recording functions. This adaptive programming function provides viewers with accurate scheduling and a flexible means of recording programs. 5.1 multichannel surround sound The MPEG-AAC scheme uses a 5.1 multichannel that consists of right/left/center stereo sound, right/left surround stereo sound and a low-frequency enhancement signal. This sound mode is frequently adopted in HDTV programming in order to enhance presence in the receiving environment. Multi-channel service (provisional programs) Sports programs such as major league baseball often extend beyond their scheduled on-air time. Usually the following programs are delayed until the end of the baseball game program. As a countermeasure to this problem, the multi-channel service involves reducing the bit rate of the HDTV encoder before the scheduled end of the baseball program. The extra capacity generated by this process is used to create an additional SDTV channel for broadcasting the extended baseball program. The originally scheduled program can then start on schedule. Speech-recognition-based transcription service Most major BS digital news programs provide transcriptions that are automatically created by converting human speech into an easy-to-read manuscript. This transcription service is also available in conventional analog TV. Message system for non-contract receivers NHK requires that a reception contract to be signed by every viewer. To notify viewers of this rule and to promote the contract, a message is displayed on screen if the viewer has not informed NHK of the installation of receiver equipment. This function is implemented by using the EMM (Entitlement Management Message) function. Hierarchical transmission to mitigate interruption due to heavy rain Hierarchical transmission helps ensure reception even during periods of heavy rainfall. Here, a low-resolution picture with monaural sound is transmitted by using the QPSK scheme simultaneously with normal picture and sound that is transmitted by using the TC8PSK scheme. In the two digital SDTV services simultaneously broadcast as the analog conventional BS service, this function operates on a 24-hour basis. In the HDTV service, a weather warning for metropolitan areas is broadcast in hierarchical mode. When the CN ratio at each receiver falls below a certain threshold, the digital receiver automatically switches from normal picture with sound to the low-resolution picture with monaural sound. This is an example of a bi-directional data service (Quiz program). A participating viewer's score is displayed based on his/her answers.