07.20.2006 11:04 AM
A Multi-Image Display Processor
Today’s broadcasters and television service providers are dealing with unprecedented signal volumes that require constant monitoring to ensure continuous, high-quality transmission and feed distribution. Fortunately, this complexity can be managed efficiently using the latest generation of multi-image display processors, which allow television facilities to perform highly flexible monitoring of dozens or even hundreds of signals.
Multi-image display processors allow multiple video, audio and metadata signals to be presented on one display, and this flexibility can be invaluable for production, in studios and in mobile trucks, as well as in master control environments. Television service providers, including cable, satellite and IPTV facilities, also benefit from multi-image displays for monitoring signals along their delivery paths to subscribers in their homes.
For most television facilities, the primary benefit of multi-image display systems is the versatility they offer by allowing video windows to be quickly adapted to suit the requirements of individual operators, different program schedules, and new channel lineups. Typically, processors can automatically detect and handle different aspect ratios (4:3 and 16:9), as well as a range of input formats (HD-SDI, SD-SDI or analog), and present them on-screen according to user-configured layouts.
A wide range of multi-image display processors is now available, depending on the image quality desired, number of inputs and outputs required, feature set, and price point, among other considerations. The starting point for multi-image display processors is the compact four-input unit, which can show four video windows per display, with full layout flexibility. Mid-size systems are typically capable of displaying around 10 windows, and larger systems can accommodate more than 30 signals distributed across more than one output or display.
Pricing currently ranges from $1,000 to $2,000 per video input, with the price depending on the quality and functionality of the processor. In most cases, the display system represents a separate purchase, and this may be a plasma or LCD flat-panel, or a rear-projection display with LCD or DLP technologies.
Typically, a multi-image display processor will allow each image to be independently sized and positioned, or displayed full-screen at up to 1920 x 1200 pixels. As a result, the operator has the ability to zoom in on any given signal to check and correct any signal problems. The image quality offered by a multi-image display processor is among the key purchase considerations. Weigh the fact that each video image is scaled down to fit within one display, and that many signals will normally share the total amount of available pixels. For this reason, the processor’s scaling system must offer optimal performance and deliver very sharp images.
While video display is the core functionality, an effective multi-image display processor provides a wide range of additional display elements that assist source identification and monitoring effectiveness. Audio level meters, source text labeling and metadata extraction and display all provide information that helps the operator on duty confirm individual signals.
Signal probing and alarming is another key capability, which helps to improve monitoring, and this may involve video, audio and metadata presence and validity. Within the master control room, for example, a multi-image display system can allow the operator to see whether all audio and video signals are valid, that metadata is properly inserted, and to confirm the programming sequence via on-screen information without having to consult another monitoring station.
In the event of a failure, obvious audible or on-screen alarms signal a problem, and a log of these alarms can be made available for subsequent investigation. Multi-image display processors can also integrate closely with SNMP-based facility monitoring systems to provide the highest level of facility control.
Space efficiency is another key benefit of using multi-image display processors, especially when they are used in conjunction with slim panel displays. Other physical benefits include reduced power and cooling requirements in comparison to using multiple CRT displays. When multiple sources are tied into a single processor rather than independent monitors, engineers also find it much easier to install, modify or upgrade their signal monitoring systems. The lower power consumption, reduced heat generation and relatively compact size make this type of solution ideal for mobile applications.
In the end, the best test of a multi-image display system is its performance in real-world applications. The input of a colleague who has experience with a particular system can be invaluable in the purchase decision, as can a demonstration provided by the manufacturer. The manufacturer, too, deserves some critical attention. If the vendor has demonstrated a commitment to the development of forward-thinking solutions that can be updated and upgraded, it can offer some peace of mind to those looking to migrate to new formats and technologies.
Louis Caron is the multi-image product development manager for Miranda Technologies Inc.