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WHRO-TV

Dec 1, 2002 12:00 PM

    

New Studios Excellence Awards Winner

WHRO, the community-liscened public broadcasting station in Norfolk, VA, for over 40 years, wanted to take advantage of one of the most important and under-utilized features of digital television — the ability to dynamically change the nature of the ATSC transmission and channel mix to suit the time of day. Their new master control and technical plant originates 12 channels including a five-channel HD/SD ATSC multiplex. WHRO wanted to provide high-quality, HD television during prime time, and provide multiple standard-definition and datacasting services for targeted audiences during the rest of the day.

Among the facility's many innovations are those included to allow the dynamic reconfiguration of the DTV multiplex. Considerations had to be taken to make sure receivers and the viewing audience would not be confused by the dynamic changes in the multiplex.

During the day while WHRO broadcasts four channels of SD programming and datacasting, the HDTV program is not turned off. Instead, the HDTV channel transmits still images and graphics promoting the HD service and providing details of the evening's program schedule. Statistical multiplexing is used to combine the desired full-motion programming with low-bandwidth “barker” channels in a single ATSC transport stream.

At night, when the HD and one of the SD channels transmit full-motion video, the other SD channels are maintained and transmit information pages.

WHRO teamed with Communications Engineering Inc. (CEI) of Newington, VA, who designed and installed the new facility.

The choice of equipment vendors centered around the flexibility and dynamic reconfiguration of the DTV multiplex. In the master control room the key elements were presentation switching/branding and monitor wall solutions capable of handling multiple channels from a single operator position. For on-air presentation WHRO selected the Miranda Oxtel series under control of Harris automation. For the monitor wall WHRO built a dual-display virtual monitor wall capable of displaying up to 12 SD and six HD signals using Miranda Kaleido processors into two Clarity Lion uXGA cubes. The ability to simultaneously display 4:3 analog, 16:9 SD and HD sources and dynamically reconfigure the monitor wall when the DTV mix is changed were key. Miranda iControl system management software performs supervision, alarm reporting and error logging of key system elements.

WHRO is presently broadcasting the five-channel ATSC transport. Its challenge now is to fine-tune both the encoding rates for the placeholder graphics and the full-motion video to maximize the quality of the signal that reaches the home.

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