For the first five years of its existence, Crown Media International relied upon its affiliates and third-party providers to originate and distribute the Hallmark Channel worldwide. Faced with rapid distribution growth throughout Europe, Latin America and Asia, Crown Media decided to build a worldwide playback and origination center in Denver.
Digital technology has enabled simplified and cost-efficient delivery of the numerous feeds to other continents via fiber and satellite. Digital broadcast equipment allows the origination of multi-standard feeds in 525 or 625 as required, using the same routing switchers, channel effects switchers, video servers and MPEG encoding systems for each. A high degree of automation allows each operator to control a large number of channels, further ensuring cost efficiency. MPEG compression also improves efficiency by allowing eight feeds to be carried on a 36MHz satellite transponder and simplifies the distribution of 32 channels to a worldwide affiliate base and viewer audience.
Centralization of distribution carries increased risks, which are addressed through careful attention to eliminating or reducing single points of failure.
The requirements are for a maximum of 32 channels of origination capability, organized into four master control (MC) rooms of eight channels each. The design of each channel is identical and may be configured for 525 or 625 digital signal format. Three VTRs per channel are utilized for long-format programming, with main and backup video servers used for short-format programming, promos and commercials. A single SDI routing switcher and backup provides all source switching for all channels. An Oxtel Imagestore 2 from Miranda implements channel logo insertion and automated effects. Each channel’s output is re-entered into the routing switcher to provide a common programming source for multiple channels and to allow for separate interstitial and segment breaks. The initial build-out provides 16-channel capability, with the potential for expansion to 32 channels.
Crown Media’s Network Operations and Engineering staff were heavily involved in developing the system concept and layout of the Network Operations Center. Aspen Engineering in Los Angeles was brought in to plan and manage construction of the physical facility. Sony SIC was chosen to handle implementation of the design, drawings, system integration and technical construction because of its domestic and international experience in direct-to-home and cable network broadcast facility design. The Crown Media project staff developed the channel design and remained immersed in the details of construction, system design and problem solving throughout the project. This level of commitment was a key factor in the success of this project.
Encoda DAL was chosen as the automation system for its ability to display multi-standard, multichannel playlists on one terminal and its demonstrated redundancy, as well as the wide range of equipment that can be automated using the system. Pinnacle video servers were also selected and Pro-Bel Eclipse routing switchers were chosen for their ability to switch both 625 and 525 in the same router frame. Another factor in the decision was that a 256x128 dual-output router occupies only 22 rack units. Scientific-Atlanta PowerVu Plus encoders and Screen Subtitling Systems were selected based on their ability to transmit six subtitle languages per channel and display any subtitled language on a standard PowerVu receiver.
Construction planning of the Network Operations Center (NOC) posed a significant challenge because the NOC was planned to occupy 4500 square feet of a commercial office building. The NOC is co-located with the Production Operation Center at Crown Media International headquarters in Greenwood Village, CO. Challenges such as the lack of a freight elevator, existing building tenants and a limited deck clearance of 11.5 feet required significant attention and planning.
The NOC is organized into a central equipment room (CER) that houses all technical equipment except VTRs, monitoring equipment and computer workstations. Master control (MC) rooms 1 through 4 contain the VTRs and monitoring equipment for eight channels each. A Broadcast Operations Control (BOC) center allows each operation supervisor to monitor 16 channels and provides the ability to take direct control of any of the channels if needed. The use of large viewing windows between BOC and each MC room provides monitoring capability in BOC without duplicating all 256 video monitors.
Electrical requirements were planned around redundant 300 KVA UPS systems, which in turn were backed up by redundant 750kW diesel generators. Both the NOC and the production facility are powered by the UPS and generator configuration. Recent rolling blackouts in California validate this decision. Each rack of equipment is supplied with a separate power source. Equipment such as the routing switchers, video servers and DA trays were ordered with multiple power supplies and AC mains; therefore, each main is supplied by a different UPS system through separate circuits. Equipment with only one power connection, such as workstations, video monitors and VTRs, is connected to AC switches fed from each UPS. These AC switches can activate a switchover between AC power sources in 6ms or less.
Electrical power, technical system interconnections and HVAC discharge air distribution are facilitated through a raised floor. The BOC uses a single 24-inch raised floor. The master control rooms are each built on a single 18-inch raised floor. This difference in elevation affords BOC greater visibility into each master control room. CER utilizes two stacked raised floors of 12 inches each. The lower floor or slab level is used for electrical power distribution through conduits and HVAC discharge air distribution. The upper raised-floor level is utilized for system wiring. Separation of the system wiring from the HVAC distribution prevents wire congestion from obstructing the airflow. This raised-floor design requires the utilization of plenum-rated cable according to most local building and electrical codes.
Three 20-ton cooling units maintain a stable temperature by forcing cold discharge air through the bottom of each rack. This design ensures an adequate airflow to racks that dissipate a significant amount of power, typically the video servers and encoding-compression systems.
Fire suppression utilizes FM-200 throughout the NOC. A double-action pressurized dry sprinkler system provides additional protection. Fire detection relies upon a sensitive air-sampling system to provide early warning of smoke. Numerous hand extinguishers are also placed throughout the facility. Security into the NOC is controlled by magnetically coded employee identification cards and biometric hand scanning.
Two environmental monitoring systems display and track HVAC, cooling parameters and rack temperatures, and monitor each generator, UPS and power distribution unit throughout the NOC and the production facility.
Redundant or fault-tolerant system design was employed to minimize any outages affecting a large number of channels by reducing single points of failure. The NOC employs redundant systems on three levels. First, the electrical power distribution systems are redundant. The failure of one circuit, or an entire UPS distribution system, will not impact critical equipment.
The second level of redundancy is source device redundancy. All VTRs are allocated three to a channel. This allows simultaneous playback of air and backup program tapes. Video servers are 1:1 redundant, and all clips are ingested into both video servers and played out of both servers.
The third level of redundancy involves signal distribution. Source switching for all channels is 1:1 redundant, with air and backup routers. The PowerVu Plus encoders are 1:8 redundant, with 1:1 redundant multiplexers. Finally, the fiber circuits used to transport the multiplexer output to the uplink sites are also 1:1 redundant.
In order to provide a seamless fail-over, all channel outputs of each router, air and backup, are fed to separate video monitors. It offers little protection to have an unmonitored backup path and find that it has failed prior to the time you need it. Additionally, all channel outputs from the redundant router are connected to SDI protection switches. Should the air router output fail, the SDI protection switch will automatically change to the backup router with minimal interruption. Each channel is re-entered into the air and backup routing switcher through separate DAs with the passive loop-through connected to the encoder for the channel. If one or both DAs fail or are removed, that channel’s encoder still has input video.
Two signal busses are utilized in the design of each channel. The first is the Program (PGM) bus. This bus has an air and backup router output assigned for each channel. Each router output connects to the SDI protection switch, the output of which is connected to the effects switcher. This effects switcher implements logo insertion, credit DVE squeezes of programs and insertion of pre-squeezed promos, all under automation control.
The second signal bus utilized for each channel is the Preset-Effects (PST-EFX) bus. This bus is configured to operate in two distinct modes. In the Preset mode, it displays the next event from a source not currently on-air. This means that if the video server is on-air, the bus will be switched to the next VTR assigned to the channel. If a VTR is on-air, the Preset bus will display the first clip or spot from the video server assigned to the channel. As in the case of the PGM bus, a separate video monitor is fed from the PST-EFX outputs of the air and backup routers. An additional SDI protection switch is present to automatically select the backup router output should the air router PST-EFX output fail.
The second mode of the PST-EFX bus is the Effects mode. This is utilized primarily in the case of credit squeezes and/or audio mix-overs, where a separate audio or video stream is required to be combined on-air under automation control.
With international channel distribution, subtitles are normally transmitted according to the demands of the local market.
World Standard Teletext allows the viewer to select one of several languages to display on that viewer’s television. Teletext is generally limited to Roman-based fonts and character sets.
Imitext subtitling is a proprietary system developed by Screen Subtitling Systems in conjunction with Scientific-Atlanta. Here the subtitles are transmitted as bitmapped images, and therefore are not limited to Roman-based characters but can include complex fonts such as Thai and Chinese. The limitation with the Imitext system is that the subtitle data is burned into the video. Once a cable headend selects a language, all subscribers view the subtitles, similar to open captioning. Imitext subtitles cannot be passed through to additional encoders or set-top boxes unless burned into the video.
Imitext subtitles are utilized in the NOC, with some channels transporting both Imitext and Teletext. At present, the maximum number of subtitle languages actually transmitted is four; however, the system is capable of six languages per channel. The Screen Subtitling Systems controller cues the subtitle file under automation control and transmits the subtitle data to the PowerVu Plus encoder in an RS-232 format, two languages per RS-232 stream.
With the ability to have common programming feed more than one channel, a problem existed with supplying the three RS-232 outputs to multiple destinations. The solution involved modifying a video DA by changing its gain structure to drive ± 10 volts into a 3KV load. With three modified RS-232 DAs per channel, each of three RS-232 streams (six languages) can be distributed to eight destinations. The ability to monitor multiple subtitle languages in the MC room required design of a three-input, one-output RS-232 switcher to allow tandem Imitext decoders to display two languages on screen at once.
Turn-up of the channels
A combination of satellite and fiber allows worldwide distribution of the Hallmark Channel from its origination point to affiliates throughout Europe, South Africa and Latin America.
The NOC was inaugurated on Feb. 14, 2001, with the launch of three channels into Europe. In the following weeks, additional European channels were launched, followed by launches into Israel, Russia, the Mideast and Latin America. Currently, 12 feeds originate from the NOC.
Charles Zabilski is vice president of operations for Crown Media International, and Darrell Lew is a Sony SIC project manager.