Multiviewers for the Big Jobs
—Advancing techologies often have synergies that we can't predict when they first hit the market. Large-screen monitors have been around for years, but the universal acceptance of high-definition has made it possible to display multiple images on a single screen.
The combination of big inexpensive flat-panel HD displays and reasonably priced multiviewers that can put a dozen or more images on a single screen has taken over the way video is monitored in production control rooms. Where there used to be 20 or 30 CRT monitors, now two 60-inch flat-panel displays that can be organized in different ways for different production styles.
The Harris HView IP multiviewer accepts compressed digital formats such as MPEG and H.264.
Multiviewers aren't limited to production control rooms. The ability to put multiple images on a single display is also common in large venues, such as sports arenas, stadiums, concert venues, conventions and whenever there are large gatherings.
In a large venue, multiviewers have a different set of requirements than those used in production control rooms. "When images are blown up onto a large display, it will expose all the problems due to scaling or de-interlacing of the source signal," said Louis Caron, senior product manager for multiviewers at Miranda Technologies. "In that case, it is important to choose a multiviewer with very high-quality scaling, as well as making sure each signal will have a de-interlacing process with high-quality filtering to reduce the visual artifacts on the edges."
STACKED TO ADD CAPACITY
The Kaleido-X multiviewer frame from Miranda can take video from up to 96 sources and feed up to eight displays, and two frames can be stacked to increase both source and display capacity. The Kaleido-X supports all manner of video, from standard-definition to 3 Gbps 1080p, and can move any image to any part of any display.
For concerts, gear is moved in and out of venues and has to be set up quickly.
"The equipment needs to be built to support vibration and shock," Caron said. "It is pretty much the same requirements when building production trucks, where the equipment will be subjected to vibration of the road frequently."
Anytime you feed video through a processing device such as a multiviewer, you run the risk of changing the timing of the video with respect to the audio⎯and in large venues, audio timing is already tricky.
"The system has to have the lowest possible video delay," said Michael Garrido, product manager for multiviewers for Harris Broadcast Communications. "Having a delay between the audio and video and whatever is happening on the field or stage is distracting, and takes away from the experience."
Attendees at major concert or sporting events expect to be entertained, and the systems better be up to that task. "A large venue will have a mixed bag of video signals, some questionable video quality [if using existing cables], as well as extremely demanding customers," Garrido said. Systems have to be able to connect to multiple standards, process the video that is available (even if it is poor) and be up and running quickly.
"The faster systems are up, the more confident the user becomes⎯ideally, systems should come with built-in defaults and easy-to-use setup software," Garrido said.
Harris Broadcast recently changed the name of its multiviewer line to "Harris HView," and it has both IP and hybrid SX versions that support any type of video. The HView SX multiviewer fits into the output section of Harris' Platinum router, making for tight integration between the router and the multiviewer.
With its IP capabilities, the Harris HView system can decode multiple MPEG and H.264 feeds from a 1 Gbps Ethernet connection, as well as handle baseband video from up to 512 router inputs.
In addition to Miranda and Harris, several companies build multiviewers that are used in stadiums, arenas and concert venues. Apantac has a range of multiviewers, including the Tahoma LE-32HD that has 32 inputs, displays up to 32 video signals, and does it in a 2RU chassis. Anticipating complex signal paths in sports and entertainment venues, the Tahoma LE-32HD has optional signal extenders that can use inexpensive Cat-5 cable.
A newcomer to the multiviewer market, Snell's recently launched MV-Series multiviewer is available in 64-input or dual 32-input versions, and can handle everything from SD to HD. The MV-Series integrates with Snell's Sirius 800 routing switcher for the ability to select among a maximum of 576 inputs. Fitting in a 3RU frame, the MV-Series has an optional backup power supply that keeps the system running in the event of a power failure.
The MVP product line from Evertz has the capability to handle any popular video format up to 3 Gbps, and can also connect to computer and graphics systems with DVI, VGA and HDMI outputs. MVP can also process IP-based MPEG video streams, and has a maximum input capability of 1,024 signals.
No matter what multiviewer you use for a concert or sporting event, remember that it is all about entertaining the paying customers. Having confidence in the multiviewer installation saves a lot of time and money.
"A good multiviewer should be able to display signals as soon as they are fed to the system, and the user can then use the setup software to customize the layouts," Garrido said. "A multiviewer has to display what it sees. Ιf the signal is bad, the system must display it as it sees it, so that the user has confidence in the multiviewer to know that the problem is upstream."
Adjustments can help tweak signals to compensate for unusual monitor placement or lights washing onto a display.
"A large display may be used in different lighting conditions, so having the ability to change the color temperature is a very useful feature," Caron said. "Ideally, it is a task for the display to provide all these adjustment parameters, but extra adjustments from the upstream processor are always useful."
Multiviewers are popping up whenever people need to see lots of information. Whether it's in a control room or above a basketball court, multiviewers help show more with less.
Bob Kovacs is a television engineer and video producer/director. He can be reached at firstname.lastname@example.org.