Beating The TrafficAtlanta integrator helps local transportation agency keep its officials and citizens off the streets by adding a high-capacity streaming webcast capability to boardroom install. 10/24/2007 8:25 AM Eastern
Beating The Traffic
Atlanta integrator helps local transportation agency keep its officials and citizens off the streets by adding a high-capacity streaming webcast capability to boardroom install.
CHALLENGE: Create a webcasting system with pipes big enough to support a huge amount of simultaneous use.
SOLUTION: Using a Windows-based PC running RealProducer Plus, route streaming video and audio to the robust broadband infrastructure of a nearby public broadcast center.
AS A PUBLIC AGENCY vested in the keeping traffic lights running, land use efficient and the air quality good, it makes sense that the Georgia Regional Transportation Authority (GRTA) would integrate virtual meeting capabilities into its boardroom activities. After all, the less people driving to its facility, the more fulfilled its mandate.
Frye says the renovation, brought a lot more features to the authority's boardroom, which also was moved to another area of the building. “It's a room where all the commissioners and board members meet and discuss the direction of new projects, finances and things like that,” says Frye. “They typically present a lot of pictures and maps while they discuss proposals or interface with officials from other agencies.”
At the heart of the project: a robust Webcasting system that lets authority officials — as well as Georgia citizens — simultaneously access live streaming video and audio of the board meetings.
According to CEI IT engineer Jim Mack, this system is based on RealNetworks RealProducer Plus software, running on a Windows-based Dell PC provided by the authority's IT department. Using the application, all audio and video generated in the boardroom is converted into streaming RealAudio and RealVideo files. Those files are then sent across the street to Georgia Public Broadcasting headquarters, which has a robust broadband distribution system.
The transportation authority has “the luxury of having Georgia Public Broadcasting and all of its bandwidth right across the street,” says Mack. The authority “can push all its audio and video signals to a great big pipe, so any number of people can watch these meetings. Any audio or video source—whoever is speaking or whatever the hot source is at the time—can be fed directly through RealProducer. And the software puts out three or four different streams, so that everything from T1 to cable (modem) to dial-up looks good.”
Also supporting the remote meeting environment is a Lectrosonics DMTH4 telephone hybrid, which integrates telephone lines and other external audio sources into the digital bus structure of the boardroom's Lectrosonics DM1612 audio processing system. These sources can operate as just another microphone or audio input in the sound system. This allows board members, while monitoring proceedings on laptop or desktop computer, to conference into meetings by dialing directly into the room's audio system (see sidebar).
Those attending the meeting speak into one of an array of 17 Shure MX418, 18-inch gooseneck condenser microphones dispersed around the room's large U-shaped table. These mics connect directly to the DM1612 audio processor, which routes directly into the Webcasting and room audio systems.
Latency between audio and video isn't an issue, because both are streamed together in real time by the Webcasting system.Board members dialing in are instructed to turn their computer speakers down before they speak so they won't be confused by the delayed audio.
In addition to the webcast, the audio processor feeds sound through one of two nine-channel, 50-watts per channel Peavey MediaMatrix Octopower 850 amplifiers. All audio in the room goes through an array of JBL Control 26 ceiling speakers.
Four ceiling-mounted Panasonic WV-CS574 color dome cameras handle video captures. The cameras are switched during meetings by an operator seated at the boardroom table using a Crestron SX-1700C control interface. While the meeting operator adjusts audio and lighting levels, there usually is an IT official on hand “to ensure the webcast goes smoothly, says Frye.
Tapped into an array of Extron switching equipment, the camera source routes to both the room's internal video display system and the web-cast.
Within the room, video — which can be everything from PowerPoint-loaded laptops to the room's native Denon DVD-1720 disc player — is displayed via a ceiling-mounted 4,500-lumen Panasonic PT-D5500U DLP projector, beaming 4 x 3 aspect-ratio images off a 100-inch projection screen, suspended on the room's front wall. Adding further video support, each board member's station has a 17-inch Panasonic WV-LC10 LCD monitor, tilt-mounted underneath a plate of glass at each position in table.
According to Troy Riner, CEI's vice president of engineering, who also worked on the project, the need to save money on wiring, as well as an overall lack of conduit space, made the integrator use Cat5 cables instead of RGB to connect the video system. “All the video is distributed over Cat5,” says Riner. “We cut holes and ran it under the floor. Doing it this way cut down on cost, as well as the size and bulk of the cables.”
Using this cabling methodology, CEI had to mount three Extron MTP T 15HDA VGA to Cat5 transmitters and two Extron MTP R 15 HAD CAT-5 to VGA receivers under the table. “At the time, the number of Cat5 transmission systems was limited, and they were more expensive,” says Riner. “But it was still cheaper than doing conduit runs.”
One of the biggest problems plaguing teleconferencing systems such as the one for the Georgia Regional Transportation Authority's boardroom, is feedback caused by the interaction between loudspeakers and microphones, according to Terry Frye, vice president of engineering for Atlanta integrator Communications & Entertainment Inc.
As sound from one end of the teleconferencing link enters the audio system and is delivered by the loudspeakers on the other end, it then enters the microphones, says Frye, and returns to the source as feedback. Listeners will hear an echo of their own speech.
To work around the problem in the authority's boardroom, CEI employed Lectrosonics DMTH4 telephone hybrid, which features adaptive proportional gain auto mixing, a technology where gain is allocated among all active channels in a seamless and continuous manner based upon channel activity. The DMTH4 also uses various proprietary echo-canceling processing capabilities.
Frye says simply using this internal noise-processing made acoustic echoes a non-issue.
“Preventing acoustic echoes was probably the biggest challenge we faced on this project,” says Frey. The DMTH4 “made it pretty standard stuff.”
Daniel Frankel is a freelance writer in Los Angeles. He can be reached at firstname.lastname@example.org