For the first time, PBS broadcast its traditional Fourth of July concert from the Washington Mall in HD. The concert is produced annually by Capital Concerts. NEP Denali provided technical facilities.
The NEP Denali Silver HD production truck is a 53-foot trailer that expands to a width of 15 feet--with flexibility to work in 720p or 1080i. PBS typically uses 1080i in its HD feeds, and for this event it fed 1080i for the network transmission while also downconverting a "center-cut" SD 480i feed for its NTSC transmission.
The production truck was situated near the U.S. Capitol building (a few hundred feet from the concert stage facilities on the mall). According to published reports, 15 Grass Valley LDK-6000 HD tripod-mounted and handheld cameras were used for the live show, including three remote cameras for long shots of the concert-ending fireworks display that were placed at elevated locations, including one on the top of the Lincoln Memorial at the opposite end of the mall.
There is a permanent fiber optic line running from the Washington Monument to near the Capitol building that was used with Video Products Group VS251 interfaces to carry the SMPTE 292M HD-SDI 1.485 GB camera signal. Signals from the two remote cameras near the White House and across the Potomac River in Virginia adjacent to Arlington National Cemetery were carried on microwave links.
This microwave aspect of the production was provided by Diversified Communications (DCI) of Washington, D.C., using its own uniquely designed COFDM radios operating in the 6 GHz band--one with a Tandberg Television MPEG-2 encoder; the other with a DCI-designed encoder--both with 1.485 GB HD-SDI interfaces and compressing to 27.5 MB with DVB-ASI connections to the radios.
5.1 surround sound was produced using a Calrec Q2 audio console in the truck, where a separate 2-channel LtRt mix was used for the NTSC feed. The six channels and the stereo pair were encoded using Dolby E onto a single AES-3 audio channel and embedded into VANC of the 1080i SMPTE 292M HD-SDI video signal for distribution.
The signals were recorded on a D5-HD VTR and on a compressed bitstream server for an immediate repeat of the program fed from PBS's distribution center in nearby Alexandria, Va. However, the concert will not be available via DVD (neither on a new HD disk format nor standard DVD) because copyright restrictions forbid the program's distribution in a commercial manner.
