Monitor walls
Sep 1, 2007 12:00 PM, BY KEVIN JACKSON
Modern video walls provide high-quality images and operational flexibility.
More than 200 Zandar Predator HD8 multiviewers drive HD video signals for the Alfacam OB fleet. Image courtesy Alfacam Television Facilities, Belgium.
With increasing numbers of TV channels being processed and served on a growing number of delivery platforms, modern monitoring environments are changing beyond recognition. The engineers responsible for running today's playout facilities need the ability not just to monitor many more channels, but to adjust their viewing priorities quickly and easily, depending on the application.
In addition to quantity, quality has become a key issue. Broadcasters have been encouraged to invest in enhanced equipment and production facilities to provide the high-quality content that will entice consumers to make the leap to HD. With HD-ready display and projection technology penetrating more European homes, there are already signs that this investment is paying dividends. However, this places additional demands on the monitor wall, which needs to be capable of handling — and displaying — HD signals at a usable resolution.
Display technology
When designing a new monitor wall, the initial step is to consider the physical dimensions of the space being used. Today's monitor walls can vary in size from two or three 23in LCD panels to huge 3 × 3 arrangements of 50in rear-projection cubes.
These cubes, most of which use Texas Instruments' DLP technology, have the potential to deliver both the highest quality images and, because of their size, the greatest operational flexibility. They also require considerably more depth than LCD screens and generate more heat. The additional air-conditioning equipment needed will take up more space and may also raise the control room's noise floor.
If rear-projection is not an option, there is little reason to fear LCD. The initial resistance of some operators to LCD technology — largely based on image-quality grounds — has weakened as the screens themselves have improved. The increasing pixel count in displays means that a large number of sources can be displayed on one screen with minimum scaling required, maintaining picture detail.
In all other respects, there is no contest. An LCD wall in conjunction with a multiviewer system will always save on wall area, depth, weight and air-conditioning requirements compared with CRT. Further space savings can also be achieved, because ancillary equipment such as under monitor displays (UMDs), which indicate channel idents, on-air status lamps and studio clocks, can be virtualized by the multiviewer.
The modern video wall has become the hub of the control room, incorporating a multitude of monitoring functions alongside the video display, while providing a flexible, reconfigurable interface to the operator. The ability to reconstruct the wall at will, change layouts, and receive dynamically updated status information and automatic fault notification has quickly become a vital functionality for broadcasters.
Signal integrity measurements and data monitoring, previously performed by separate devices, are now found in the multiviewer, where the operator can recall their status to the monitor wall. Audio metering, channel IDs and tally status, once displayed on separate devices within the control room, are now routinely routed to the video wall.
However, the increasing number of channels makes it more difficult for operators to simultaneously observe the required number of sources. When designing a monitor wall, it is more important than ever to consider operator comfort. How many operators will typically need to sit at the wall? How far from the screens will they be? What control surfaces will they typically need easy access to?
Symptoms such as eyestrain and back strain are all too common in control rooms where functionality and ergonomics have not been properly considered at the design stage. Operators who are suffering from this kind of condition are more likely to miss key on-screen messages.
Adding an appropriately specified multiviewer to a monitor wall can help to alleviate these problems before they occur, because a multiviewer gives operators the flexibility to instantly resize and reposition images, depending on the playout schedule. With a multiviewer, operators no longer need to stretch to view a particular image because it is positioned too far away, or squint at a picture because the screen displaying it is too small to show sufficient detail.
Operator comfort is also a reason why, in large production centers, it has become necessary to automate the monitoring process, allowing the video wall to notify users of any errors or unexpected events. Often, it is also necessary to notify other pieces of software that may be used to control the entire production chain.
| Want to use this article? Click here for options! |  |
