In an ideal world, the master control operator in a TV station could sit anywhere on the planet. He or she would be able to see images in essentially real time, interact with the automation and archive in a Web browser, communicate like the control room was right in front of him or her, troubleshoot problems with hardware, and even replace equipment that has failed. All this could be done from a home office while sitting on the couch with a laptop. Is it far-fetched? Not these days. Let me explain.
Why distance doesn't matter
Modern systems have become incredibly complex even as computers and networking have allowed an array of capabilities no one could have imagined 25 years ago. DTV ratcheted up the complexity considerably in the last few years, with multicasting and ancillary services that make broadcast monitoring and control systems look as much organic as deterministic.
Some modern technologies have in fact simplified systems. For example, modern master control systems often incorporate branding (we used to call it keying) with switching and even clip playback. Such devices allow control systems to address more elements of the program assembly process with fewer control paths. But, of course, that comes on the double-edged sword of increased communication complexity. Other systems make life easier, such as archives that in one view replace shelves and manual filing of physical media.
I would submit to you that all of these systems require monitoring and control from an indeterminate distance away in order to function. Putting the devices in the same room with the operator does not make a dime's worth of difference. The only interaction one can have with them is over a monitoring and control system, and in the case of picture and sound processing equipment, we interact by watching and listening to the effect of our commands. Thus, monitoring and control, along with the local version we sometimes call user interfaces, are critical elements of managing processes in broadcast plants.
In the case of some software products — for example, playout automation — the interaction may be through a user interface as the primary tool. However, few modern automation vendors build products without the ability to run over a network some distance from the actual computers.
In the case of systems without such Web or remote capability, it is normal and even expected that a KVM switch will interface to a multiplicity of processors. Often it is possible to extend the KVM over networks. If not, you can use remote desktop or thin clients to make distance largely immaterial.
Monitoring the right parameters
A critical element of any remote monitoring and control system is managing bandwidth and latency. Many applications expect a continuous stream of interaction, and extending over long distances arbitrarily may not work if the application times out before acknowledgments are received. One must be thoughtful and cautious when creating a control and monitoring topology. Increasingly, you need to look carefully at networking issues. Opening ports through remote firewalls to support the communications needs of a specific application may be possible, but the IT gurus may become intransigent when you ask for Port 80 (HTTP) to be open to the world.
The bandwidth may also be an issue. The biggest hog of bandwidth is video monitoring. Low-latency video codecs tend to use more bandwidth though dropping the resolution can move the bandwidth needle the right way. Some streaming applications can adapt to available bandwidth — for example, Microsoft Silverlight. By reserving bandwidth in the router for critical applications, you can prevent video from overwhelming other needs.
It is useful to ask what the video is being used for as well. In a remote master control system's thumbnails, every 30 seconds can verify feeds are being delivered to remote cable or DBS services. The output of network receivers may require close to 30fps, though QCIF or even lower resolution may suffice for normal situations. If you are troubleshooting a lost or poor-quality feed, it might be useful to have a codec on a small router that can look at outputs of critical paths. Defaulting that router to black and using variable bit rate encoding can throttle the utility path to a low bandwidth and preserve space for other applications. (See Table 1.)
Setting up self or directed healing
There is another class of monitoring that is in many ways even more important. Most modern broadcast devices above a minimum level of complexity include onboard components monitoring their health and operational status. Often that information is gathered by an application written by the manufacturer, or Simple Network Management Protocol (SNMP) applications. In previous generations of equipment, one had to look and listen to determine if a device was operating properly. For a time, some devices featured relay closures to set alarms for power supply failure, or perhaps fan function.
In modern digital equipment, the range of parameters monitored is limited only by the creative energy of the design team and, of course, money. A frame sync, for example, might sense picture or sound presence, levels, local device temperature and power supply voltage. The data is passed to a frame controller and then to an application for logging, alarming and display on a user interface. If a device fails, or a parameter is out of tolerance, the user interface may send a text page and flash a warning. This enables operators within easy line of sight to see the condition develop. Someone at home for the night, responding only to emergencies, would receive a notice to log on to a remote application and get the full detail before driving in to fix the problem.
Defining true remote monitoring/control
In the end, the intent of many remote monitoring and control systems is to allow systems to be fixed remotely. A routing switcher might disable a failed crosspoint card and activate a replacement. A dead frame sync might be replaced by a routing switcher programmed to have backup paths for critical signals. All of this can be done from an arbitrarily long distance if the system is set to monitor the right parameters, communicate the fault effectively, and allow self or directed healing.
In such a system, a hypothetical master control operator may be in another room, or even another city. I have clients who monitor systems from continental and intercontinental distances successfully using easily deployed tools. That is truly remote monitoring and control.
Table 1. Common image format resolution Format Video resolution SQCIF 128 × 96 QCIF 176 × 144 CIF 352 × 288 4CIF 704 × 576 16CIF 1408 × 1152
John Luff is a broadcast technology consultant.
Send questions and comments to:firstname.lastname@example.org