Multiple-Image Display Processors
Jul 1, 2003 12:00 PM, Bennett Liles
During the past 40 years, slowly converging technologies have brought the multi-image projection display industry down a long and winding road to its present state. Each of its three component technologies — source, control, and display — has seen its own advances on the way to a modern union.
While they made news, analog control schemes were quite expensive, complex, and error-prone. Sources consisted largely of photographic slides and movie screens that appeared as a postage stamp from 20 feet. Digital sources and control systems have brought a quantum leap to large, multiscreen audiovisual presentation, and display technologies have seen an explosion in both size and variety. These advances in source, control, and display have brought forth a dizzying array of formats that dictate versatility as a key factor in the modern multi-image video processor market.
Developed on the cusp between analog and digital worlds, today's processors must handle and seamlessly integrate analog composite, YUV, RGBHV, NTSC, PAL, SDI, interlaced and progressive-scan sources, HD, and others in any combination. If there is one capability that stands out in the newest multiscreen video processors, it is this multiformat mode and the ability to automatically recognize and integrate the plethora of new video and computer sources while providing output compatible with an equally wide range of display devices. These include the venerable CRTs, various projection cubes, and flat matrix imaging devices including liquid crystal displays (LCD), plasma display panels (PDPs), and light-emitting diode (LED) displays. Further complicating the issue is the variety of aspect ratios that exist among the various standards. Sources and displays can require the integrated use of 4:3 for NTSC and PAL, 5:4 for SXGA, and 16:9 for HDTV.
ONE TO MANY — MANY TO ONE
One feature that typifies the advances and new versatility in multi-image video display processing is the ability to project one source over a wall of separate cubes or screens and to display many sources on one large display screen. This feature substantially widens the market applications for the top-end multi-image processors. The many-to-one applications create a virtual video wall used in big-show multimedia displays and educational environments where they can demonstrate synchronized movement with narration or music and eliminate the blocky, thick-mullion video walls of the mid-'80s. Temporary setups are typically made much easier by erecting one large screen instead of building a frame and stacking dozens of projection cubes. Projecting many sources to one screen offers a huge degree of flexibility.
One feature that has enhanced such many-to-one displays is the use of multiple Z-orders. Graphic artists have long recognized Z-orders as referring to the dimension of depth in stacking sources on the screen. The higher the Z-order number, the closer the displayed source appears to the viewer. A 1Z source may be completely hidden behind a 2Z source or partially slid behind it like one sheet of paper halfway under another. The newer processors offer a dozen or more Z-orders for the various input sources. One application area that can make use of a many-to-many display scheme is the realm of command and control. Transportation centers, power plants, broadcast control rooms, and videoconferencing are examples of applications for multiple sources to be processed for multiple screens. The latest equipment features the ability to transition instantly between any of these display screen modes, either manually or by preprogrammed commands.
One basic parameter of modern multiscreen video processors is the number and variety of input sources that each model handles. This is usually determined by the choice of an assortment of input modules or cards that can be inserted into one or more card cages. The latest models take that inserted card concept to most other aspects of the operation, including hot-swappable output cards and even hot-swappable power and cooling fan modules. This idea brings a great improvement in two important hardware specifications: Maximum Time Between Failures and Mean Time to Repair.
On most models, the type of inputs desired will determine the selection of input card types. The array of input cards available can eliminate the need for external line doublers, decoders, and digitizers through direct support for composite, S-video, component, RGB, SDI, and DVI with automatic detection of both NTSC and PAL input source signals. Some multi-image video processors will accept a whole range of source formats on any input with total autodetection and configuration, making things even easier to set up.
The output cards are similar in function with the ability to custom-tailor the number and type of outputs and connectors for the number and type of display devices. On most of today's top-end processors, each output card can access any inputs in any combination, can autoconvert formats, and can be controlled through a proprietary terminal or with Windows, Linux, or Unix control applications running on generic notebook or desktop PCs.
Each one-, two-, or three-rack unit card cage contains anywhere from 2 to 16 common PCI slots to connect the input and output channel cards to the system. On most models, each card includes multiple input or output channels, and more card cages can be added for additional capacity. For internal storage and display of disk-based source material, sizeable hard drives are housed in the processor's case along with multiple, redundant power supplies and a computer network interface card for operation in a variety of remote control scenarios. Both LAN and Internet connectivity are possible with software configuration.
THE USER INTERFACE
This is where the creative fun starts. Many manufacturers now offer a graphical user interface that shows a familiar drag-and-drop style of setup and control. Through this easy interface, operators can use a range of configuration parameters, including and excluding individual channels from group operation much like the manipulation of digital lighting boards and sound mixers.
Most of the control interfaces feature a display box with the user-defined overall dimensions for the presentation. Within that box can be drawn individual screens or other predefined areas. Sources are graphically dragged and dropped into the individual screen or general screen areas they will occupy in the presentation. Once these assignments have been made, a completely new screen plan can be set up and a transition can be programmed between them for the ultimate in display mode versatility.
Each source can be individually programmed for full display within its own screen area or for a reduced or cropped appearance known as viewporting. Colored borders may also be used. Any image can be displayed totally inside the overall presentation area or shown with a portion of it outside the viewed area. Each source can also be programmed to move in any direction around the larger display or within its own smaller area and can simultaneously change size. This shrinking and growing display feature is generally known among the vendors as minification and magnification. Any screen can become an area of color. This is called a color wash, and the hue and saturation can be programmed to change continuously or on command.
Add the Z-order capability, and the creative possibilities are almost endless. Many of the control interfaces can label each screen or designated display area, and some even enable camera tally displays for broadcast control room applications to identify which camera is one the air (red) and which ones have been routed to isolated recorders (green). In sports coverage, these “iso-tallies” are used to identify the cameras being assigned for instant replay.
Electrosonic has introduced the Vector system for multi-image video processing. Setup and control is done through the use of Electrosonic's C-Through control software. The software comes with a variety of special show effects that can be stored on the Vector System Manager card. Standard and high-resolution output can be mixed in a single Vector system. Input cards are available for analog video, digital video, and computer inputs, and each card offers one or two input channels. Entire shows can be internally stored and started remotely. The aspect ratio of each image can be shown to match the source or may be shown with an anamorphic stretch.
Clarity Visual Systems markets its Digital Media Controller primarily for Digital Visual Messaging solutions. As such it is more limited in its selection of video formats (AVI, QT, MOV, MPG, and MPEG), but within this realm, it offers an array of imaginative control options through a wireless mouse or wireless keyboard. It supports a wide range of still graphics formats, and it is all controlled through the SignSuite media management software running on the Windows 2000 platform. SignSuite comes in four software modules. Show Builder allows management of still images, animations, text, movies, and Web files and allows these elements to be controlled in timing, transition effects, placement, and size. Scheduler allows daily and weekly scheduling of displayed events. Show Station configures the displays for banners, walls, single screens, or towers. Remote Station allows manual remote control by LAN for nontimed messaging displays.
Imtech has entered the fray with Activu, a softwarecentric solution with no proprietary hardware. Activu runs on standard servers using standard graphics cards and can be controlled on existing LANs. Imtech has reasoned that it is far easier to keep costs of development and operation down by allowing its software to run on a wide variety of readily available servers rather than taking the proprietary approach. The company points out that this minimizes the cost of hardware upgrades and allows a superior degree of hardware customization for the application at hand while Imtech offers software upgrades to existing customers at no extra cost.
Jupiter Systems presents its Fusion 970 as its top display wall controller in the Fusion Series. The Fusion 970 can drive 50 analog or digital projectors to a maximum resolution of 1,600-by-1,200 pixels per projector and can handle 32 composite and 16 S-video inputs per 8-rack unit chassis. The system contains four hot-swappable power supplies and three blowers in hot-swappable canisters. Users can add eight 4-port, HD-15 RGB input cards to display images from computers and legacy systems. The ControlPoint software runs on Windows 2000 and enables the system to interface with UNIX and Windows XP-based computers and touch-panel devices from AMX and Crestron. A 36 GB SCSI hard drive is standard.
Miranda Technologies' versatile Kaleido-K2 can handle 32 inputs with a maximum resolution of 1,600-by-1,200 pixels, and it can mix and match SDI and analog video in PAL, SECAM, and NTSC along with computer signals from 640 by 480 to 1,600 by 1,200 (VGA to UXGA). The unit can also handle inputs in aspect ratios of 16:9 or 4:3, and streaming video can be inserted as full screen or as picture-in-picture. Under-monitor displays (UMDs) can be placed onscreen and dynamically updated with the UMD controller. But video doesn't get all the Kaleido's attention. Configurable audio metering is displayed outside the video image or in transparent mode inside each picture in ballistic or scale metering, and audio phase metering can be presented. As many as three audio input modules can be used, each with 16 input channels. For control room applications, multiple clocks and timers can be shown in digital and analog configurations. These can each count up or down and are controlled from the Kaleido-K2 remote control panel or through external TCP-IP commands. The Kaleido-K2 will let you know when things aren't quite right. Each input channel can display signal status or validity and alert the operator to many errors including video level and audio phase trouble. All active modules contained in the four RU chassis are front loaded, and the unit has redundant output modules and hot-swappable redundant power supplies.
RGB Spectrum brings its Superview 3000 into the arena with a range of control options including the unit's front panel, remote operation by RS-232 port, or from any PC or workstation running its optional VCP software on a Windows 95 or higher operating system. Inputs may be NTSC, PAL, S-video, FLIR, or any computer signal up to 1,600-by-1,200 pixels. The display's overlapping or side-by-side windows can be panned and zoomed, and the output resolution is user-selectable up to a maximum of 1,600 by 1,200. A DVI digital output is available, and a genlocked source can be displayed in the background. The overall display can be made in 4:3 or 16:9 aspect ratios. As many as 36 inputs are supported, and each is independently controllable in position, zoom, and size from an icon up to full screen.
Zandar Technologies offers its FusionPro High-Resolution MultiViewer in a modular architecture featuring a combination of input formats, including analog video, SDI, HD-SDI, DVI, and computer through the use of user-installable processing cards. The FusionPro 3 RU chassis can handle 13 dual-channel input cards for a total of 26 input channels. The 1 RU accepts four processing cards and supports eight scalable windows. Dual redundant power supplies are available as an option with the 3 RU. The FusionPro supports resolutions up to SXGA (1,280 by 1,024) and UXGA (1,600 by 1,200) with image quality achieved through 10-bit RGB outputs, an advanced video-processing engine, and dynamic phase adjustment for accurate pixel mapping.
When used in its graphical background mode featuring a choice of computer-generated backgrounds, the system automatically uses the timing and resolution of the computer graphic background. User display configuration is provided through Layout Editor software, supplied as standard. Remote control is over RS-232 or RS-422/485, while multisystem control is provided by Z-Manager software. FusionPro supports in-picture audio metering and dynamic UMD and tally status display.
This is an exciting time for multi-image video display processors now that the digital source and display technologies have converged and computers have enabled digital processing to bring such an endless array of creative control options.
Bennett Lilesis a freelance television production engineer and audiovisual technician in the Atlanta area specializing in government video production, distance learning, and videoconferencing.
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