Northern Virgina Community College

Follow along as this community college transitioned its production from ¾-inch U-Matic videotape to a SAN-based system using magnetic and optical discs
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NVCC’s new automated and tapeless control room increases the programming to 24 hours a day while reducing the labor to less than 20 hours a week.

Northern Virginia Community College (NVCC) served more than 300,000 students in credit and non-credit courses the 2001-2002 academic year. Its television center broadcasts over cable to Arlington, Fairfax, Loudoun and Prince William counties and the city of Alexandria.

The television center recently underwent a project to eliminate all tape formats. The primary goal of the project was to store video and audio data centrally in a 7TB RAID-5 system and to use a 2GB/s Fibre Channel to share data among computers. The secondary goal was to reduce the personnel needed to run the cable channel so they could be assigned to other duties. And, of course, the total expense of the project had to be kept to a minimum. The project was carried out in five phases.

Phase 1, June 2000: Master control

At the heart of the completely tapeless system is a TiltRac hybrid server system, which uses DVD-RAM for archive. The server will act as network-area storage until the new 8TB storage-area network is installed.

The new master control room was an old broadcast studio that had not been used for years, located next to the existing control room. The empty studio was a clean slate; it needed power, AC and raised flooring. The old equipment consisted of eight Sony VO-9600s controlled by a Matco-A control system.

The heart of the new control room is the TiltRac (now Synergy Broadcast) master control system. It includes a master control computer, an online server, two video encoders, a Web encoder and a digital archive unit (DAU) with DVD-RAM media. The online server can hold 100 hours of programming at 8MB/s and output eight independent video streams simultaneously. If the first selected output channel fails, the system can reconfigure itself to play a video file on another output channel, if there are other channels open.

The audio production room handles all of the audio needs for the 53x31-foot studio, voice-over booth and Sony’s ACID 3.0 audio workstation.

Each of the two encoders has its own 60GB hard drive. The encoders are configured to record most shows at 6MB/s in MPEG-2 long-GOP 480p, but they can be set up to record an encoder level of 10MB/s. As mentioned earlier, the online server only holds 100 hours of video, but the station has over 1500 hours of video stored on DVD-RAMs. The DAU holds 500 9.4GB DVD-RAMs and has a maximum capacity of 4.7TB. But that capacity is possible only if each disc is filled to its capacity. To avoid dropped frames and other playback discontinuities, the data for each show must be recorded contiguously on the disc. Each side of a 9.4GB disc can hold 4.7GB. A typical hour-long encoded show uses about 2.5GB, and a half-hour show uses about 1.25GB. Thus, a one-hour show and a half-hour show (a total of about 3.75GB) can be stored on each side of a disc, leaving about 0.95GB per side (1.9GB per disc) unusable. Another problem is that erasing old programs and re-using parts of a disc for new programs sometimes leaves only half of the total disc space usable. So, in practical terms, the capacity of the DAU is actually closer to 3TB.

The production studio engineer position controls the video levels, encoders and client copy tape decks.

Originally, all the IP data passed through a Netgear eight-port switch. But, the college installed a VoIP phone system and it needed a switch that was controllable. So it replaced the Netgear with a Cisco 3424. All the signals pass through a Sigma Matrix 32x32 audio-follow-video stereo router.

A Leitch DPS-575AV digital processing synchronizer provides auto level control and final adjustment of the video and audio signals at the cable headend. Also, it is configured to insert on line 19 odd, which has full field bars for test and level control for the entire cable system. In addition to the test signal, the station uses the keyer option on the synchronizer to insert the college’s logo. The logo can be replaced with a school-closing lower-third as needed.

The old master control signal was run into one of the Sigma router’s inputs so the college could run its programming while the shows were going through the encoding process. After most of the college’s programming was encoded, the old master control system was turned off and the router input was converted to a PowerPoint trouble slide. After a semester of running the normal programming schedule, the college decided to increase the total programming to run 24 hours a day.

Phase 2, July 2002: Studio control

Nonlinear editing is done with two Dell Precision 650s and Sony’s Vegas 4.0 with DVD authoring software.

The studio control room equipment was as old as the master control equipment. Studio control was crammed into a 10x15-foot room, leaving little space to walk or sit. The plan was to divide the audio and video equipment into separate rooms and upgrade the entire plant to a tapeless format from 3/4-inch U-Matic. It would cost less than an upgrade to a digital tape format and would make the plant more efficient. If the file is already in the computer, why record it to tape, record it back into the edit server, perform the editing, then record it back out to tape for the final encode back into IP? It would be much easier just to send the file over the network to the computer station that needs it.

All of the monitors for the technical director position are routable.

The college moved the video equipment into a 10x15-foot room next door and the audio mixer from its 6x8-foot room into the larger space where the video equipment used to be. The old audio room became a desperately needed voice-over booth. At the heart of these rooms is a Sierra Video Tahoe router. The Tahoe is configured to handle video separately from the audio through three router controllers, saving the cost of buying separate routers. The controllers for the router were placed in the audio room, the technical director’s station and the engineering station. Only the engineering station can change both audio and video from the same controller.

To handle the video needs for the studio control room, another TiltRac encoder and a smaller online server were purchased. Because TiltRac made the equipment in the master control room, the files pass between the two rooms without any problems. The online server has half the storage of the master control system and can output only four video streams. The encoder is identical to the two in the master control room.

The audio side is mixed through an existing Mackie 24-8 and captured into the TiltRac encoder computer or a digital audio workstation (DAW). Then the DAW is used to create new audio beds using Sony’s ACID, which are then sent to the NLE for insertion into the video clip. The video side uses an existing Echolab 6. The final output from the room is captured into the encoder. When the file is complete, it is sent over IP either to an NLE or to the master control online server for air or archive.

Phase 3, November 2002: NLE systems

Figure 1. Flowchart of connections to SAN Click here to see an enlarged diagram.
The NLE systems were placed in the redundant master control room, which had not been used for more than five years. Paint and new carpet were the only things needed to prepare the edit room. Two Dell Precision 650s were purchased for NLE. The computers have dual 2.8GHz processors, 2GB RAM, 100GB RAID-5 storage and a DVD+R burner. Vegas with DVD authoring proved to work with the TiltRac MPEG-2 long-GOP 480p file format. Prior to the purchase of Vegas, the facility used Adobe Premiere. The system was used to convert the files to AVI, then back into MPEG-2 on the final render — a time-consuming process. The raw field video was recorded into the Laird DV drive, then dragged and dropped onto the NLE drives. When the final program was rendered, the file was transferred either onto the master control online server and archived in the DAU, or burned into a data or video DVD-ROM.

Phase 4, July 2003:

Table 1. Breakdown of costs for converting to a tapeless plant. Click here to see an enlarged diagram.
Backup online systems and Web streaming With the addition of a second master control computer and a second online master control server, unscheduled downtime is reduced to less than 15 seconds a year. This low downtime is possible because the redundant and primary systems simultaneously play the same file. When there is a problem with the primary system, an automatic router switch puts the backup system on-air. Web streaming is done through two servers: an off-site, third-party host and an intranet server that both output 300Kb/s Windows Media streams. All VOD telecourse files are located on the intranet servers to prevent unauthorized viewing. The students have to be on campus and sign onto the streaming page with their user name and password to access the files.

Phase 5, May 2004: SAN

The broadcast center will use the TiltRac servers as network-area storage until the storage-area network (SAN) can be purchased. The SAN will add a lot more storage for online files (including Windows Media files) and production files. Figure 1 shows how the SAN will connect to the other station devices. All the files for the station are kept on the SAN’s seven usable terabytes. The SAN also uses a 2GB/s fiber backbone to reduce data-transfer times dramatically. Transfer time over 10/100 Ethernet was reduced from 15 minutes to two minutes. Another plus is that, if a computer is connected to the Fibre Channel, the SAN behaves as a local drive for that computer — eliminating the need for data transfer. The SAN will be set up in a RAID-5 configuration and will serve as both long- and short-term storage for the television center’s data. Reducing the digital archive’s workload will allow it to be what it was designed to be: a true archive.

Some snags

Finding an NLE system capable of handling the Synergy-encoded MPEG-2 long-GOP 480p file format was time-consuming. For the first year, a product simply was not available. Encoding all the video into the system was a time-consuming process, with each show taking 1-1/2 times as long to process. The SAN has a 2TB storage limitation. This is not a problem yet. But, with HD files or other large file formats, it could become an issue. Asset management is becoming a concern as well, with multiple copies of the same file, or revised copies of files, stored in multiple locations in the system. Another issue to be resolved had to do with the college’s virus checking software. It slowed the data tranfer rate from 2GB/s to 100MB/s, and had to be turned off.

Benefits and costs of tapeless operation

Transferring files over IP, rather than tape, has improved the quality of the facility’s product dramatically, as well as reducing the time it takes to finish a show. This has led to 24-hour programming. Before, when the station was off the air, it aired a PowerPoint slide. Now, the station runs a selection of programming and college promotional material. The new system has reduced maintenance cost and repair time greatly. The labor for master control has been reduced from 96 hours per week to less than 20 hours. The personnel that maintained and operated master control have been moved to other positions in the television center. Table 1 shows the approximate cost for each phase of conversion. The total cost of converting to a tapeless plant was about $500,000.

Trenton J. Mengel is the chief engineer at NVCC’s television center.