By Micah Stevens
At North Point Ministries we have built a video broadcast system that connects four separate auditoriums in three different locations across metro Atlanta. Buckhead Church and Browns Bridge Community Church both are approximately 20 miles — in opposite directions — from our North Point campus, located in Alpharetta, GA.
We primarily transmit the message portion of our worship service between these campuses every Sunday and for special events. We have equipped all four auditoriums with nearly identical video equipment including cameras, switchers, media server systems, projectors, and screens so that all venues can originate and receive content in the same way. At each auditorium, personnel use local video control rooms to manage live, local service elements such as music, announcements, and video playback.
Working with systems integrator Clark (formerly Clark ProMedia), we installed Omneon Spectrum media server systems in each video control room, thus enabling our staff and volunteers to record and perform time-delay playout of the service elements that are broadcast between campuses. We send two synchronized video signals to each campus, and these are ingested on the Spectrum server and then played back on delay anywhere from 45 seconds to 12 minutes later, depending on when they are needed at the campus.
This portion of the service makes up two-thirds of our service time, and with this part of our service being the most mission-critical, we needed proven reliability. By giving us time-delay playout capability, the systems alleviate the need for all service elements at our locations and auditoriums to be perfectly in sync. Using the media server systems, we’ve also been able to achieve much better video quality than we did with previous solutions and greater flexibility in bringing creative elements into the worship service.
Virtual set model
To create the most engaging environment possible, we use a virtual set model. Using HD and SD video systems, we capture and present separate images on multiple screens that are perceptually identical to the original environment. Positioned on either side of the stage, two screens measuring 18.8 feet by 10.5 feet show close-up IMAG (image magnification) camera shots and graphics. A single 28-foot by 16-foot drop-down large-format screen is mounted center-stage, extending down from the proscenium to the floor.
Throughout the service, a simple and unchanging view of the stage and set is projected on this center screen in HD. The wide shot captures a comprehensive view of what happens on the stage and portrays the communicator moving across the stage in lifelike proportion. The combination of all three screens at a viewing campus makes a “virtual” copy of the original live environment.
The SD video system at each campus consists of six to eight cameras, graphics computers and Omneon Spectrum media servers, all connected to a switcher. At the originating site, the switcher’s output is fed through a router to multiple in-house destinations including side-screen projectors, plasma displays, digital tape recorders and hard drives, as well as to the video control rooms at receiving campuses. The feed is recorded onto an SD channel of a local server at the campus. At the appropriate time, staff or volunteers can trigger the server system to play recorded content back through the local switcher to the side screens.
HD signal is sent to multiple destinations
In the center of each auditorium, a single HD camera is mounted on a robotic pan/tilt system to capture the static wide shot presented on the center screen. Delivered along with the SD signal, the HD signal also is fed through a router to multiple destinations including digital tape recorders, hard drives and other campus locations. We send the HD signal through a hardware JPEG 2000 encoder, which encapsulates the JPEG 2000 compression as a 10-bit uncompressed SDI video signal.
This enables us to transmit our HD video signal down fiber lines that are identical to the lines used for the side-screen SD feed. At the receiving campus, the HD signal is recorded locally on an SD channel of an Omneon Spectrum system operating as a delay server. The SD signals thus can be triggered in parallel — with the JPEG 2000-encoded signal being decoded after server output — to deliver video to the center and side screens in sync. Using this method of transmission and recording, we need only compress and decompress the HD video signal one time between capture and audience viewing.
The dual-channel media server installed in each control room simultaneously records two incoming video signals side by side and associates them to a single reference file. The content can then be queued and played in synchronization before the files are even finished recording. The receiving campus locations start recording the content as it happens in real time, and then simply play it out when they are ready.
So far, our media server systems have performed incredibly well. There have been no on-air failures to date and little to no maintenance has been required. In addition to providing ease of use for end users, the Omneon Spectrum systems give our technical staff the flexibility to support and configure systems remotely over our wide area network.
Micah Stevens is production director of North Point Ministries, Alpharetta, GA. [www.northpoint.org]