Digital System Technology (DST) recently completed a comprehensive IT systems integration project at Crawford Communications in Atlanta for an automated, server-based, multichannel master control system.
It is hard to believe that 10 years ago those of us on the various teams charged with designing and building the Grand Alliance prototype were working feverishly at Sarnoff Research Institute in Princeton, NJ, to finish debugging the ATSC HDTV prototype. There had been numerous delays and ACATS and everyone else involved were anxious to resolve these final problems and ship the system to the ATTC in Alexandria, VA, for the FCC testing process. By the end of March the racks were on their way.
Testing was completed in 1995 and in November the ATSC system was recommended for adoption by the FCC. We’d all have HD sets by 1998. But the battle that technology had raged for nearly a decade and found peaceful coexistence in the Grand Alliance erupted on new fronts. The minor attacks the computer consortium had mounted over the progressive vs. interlaced scanning format became a battle and was settled only after FCC Commissioner Hess intervened. Resolved by the end of 1996, the ATSC DTV standard was “good to go.”
Other battles occurred. One HD or four SD services and VSB vs. COFDM issues stalled the transition. It was the chicken and egg syndrome: There were no HDTV viewers, so why broadcast? There were no broadcasts, so why build HDTV sets? And what about a cable HDTV standard? Each of these issues, to one degree or another, has been resolved.
Yet still, as of Jan. 1, HDTV is the exception in viewer living rooms.
BOC transition
This is a difficult time for veteran broadcast engineers. The proliferation of IT technologies in the Broadcast Operations Center (BOC) has forced many of us to go back to school. We have built careers based on sound engineering practices and now we have to start all over again. We often find that freshman technical personnel are more proficient in IT technologies than we can ever hope to be.
Most broadcasters have been engaged in a new war: broadcast engineering vs. information technology. The computer industry claimed it had all the answers for the TV business. But at NAB2000, the broadcast and computer industries kissed and made up, as evidenced by the Sands IT exhibition and the related conference topics.
Where is the IT in broadcasting?
What exactly do we mean when we say that broadcasting is undergoing a transition to digital? Serial digital audio and video signals have been used and distributed in BOCs for nearly two decades. Do we really mean to say a transition to a compressed file-based infrastructure? Will media asset management (MAM) systems replace tape? No more sneaker-net!
The truth is that the media business in general is evolving toward a new engineering discipline. It is not the marriage of broadcast and IT, but their offspring. So let’s discuss the difference between broadcast engineering and information technology.
The issues
Program elements in the broadcast domain are continuous signals in real time. IT in broadcasting deals with compressed media files transferred at greater than real time rates. Continuous essence streams do not require buffering.
Gigabit means one billion bits per second. In the IT realm, this is a theoretical number where the number may or may not specify a certain bandwidth. What transfer rate really takes place on a so-called gig pipe? Is it 500Mb/s or 700Mb/s? What about collisions? In other words, it may not really be a gig’s worth of bandwidth. On the other hand, as of 1997, the SMPTE 292 standard specifies sustained, real-time transfer rates of 1.5Gig HD signals as commonplace. For broadcasters, 1.5Gb/s means 1.5Gb/s.
On the other hand, IP-based file transfers give one the freedom to route any signal anywhere. Packets can arrive out of sequence or be delayed and then be reassembled at the other end. Unfortunately, video signal transfers are intolerant of any variable delays. To improve video delivery, the IT world is moving toward switched circuits and away from routers. This is exactly the kind of composite and SDI routing that has been done for years in a broadcast infrastructure. It seems that video router methodologies are where the IT network world is finally heading.
There may be a dozen or so essence transfers, video or audio, moving around the broadcast infrastructure at one time. How will this traffic be segmented? If file transfers are at four times real time, will it only take six hours to move a day’s worth of programming? On the negative side, one hour down means four hours of real time content lost.
Then we have software
Software is patched every few weeks, upgraded every few months and replaced by a new version every year or so. Where is the maintenance window to make these all too-frequent upgrades and install these absolutely necessary patches in a 24-hour broadcast environment? And what about new bugs with new software version releases? In the broadcast world, it’s not about features or bells and whistles: it’s about reliability.
And hardware
Finally, we have IT hardware issues. Computer hardware is often junked and replaced about every two years. Broadcast infrastructures typically operate with a philosophy similar to the military: if it ain’t broke, don’t fix it. Technical standards that require an infrastructure’s overhaul rarely occur in the TV business. The transition to digital has become the exception.
In our world, there is one SDI standard, one ATSC standard, etc. How many “Ethernet” standards are there? The many co-called “standards” and their typical short lives has always been a key problem with the computer industry’s interference rather than cooperation in the development of the ATSC standard. Just-in-time standards setting does not represent good engineering practice.
Problems that impact the on-air product must be resolved instantly. A burp in a commercial spot or a cue tone failure can require make goods and other business repairs that directly impact the bottom line. The computer industry did not initially grasp these demands.
Here’s the IT version of calling the broadcast equipment help desk. “Thank you for calling the BOC help desk, we are happy to serve you. Press one for an on-air problem; press 2 for all other problems. You pressed one. Now, please press one for PCR problems, two for MCR problems…” All the while the cost-time dollar clock is ticking.
And then there’s the reliability factor. Do you want to re-boot a piece of equipment when it is fourth and goal, with two seconds on the clock and the Super Bowl victory on the line? Even having to reroute the signal through the facility could interrupt the broadcast.
Our new world of IT has introduced us to an environment of Internet worms, viruses and other forms of computer attacks that threaten to knock a BOC off the air. Every networked resource can become infected. If it does, complete eradication of the infection will at least be time consuming or even impossible.
Security in the IT world begins with a user ID and password. A user profile is created that grants certain access rights to various network resources and software applications. Logging onto the system establishes your access rights and privileges. Rings of security using Firewalls, DMZs and access filters coupled with Intrusion Detection Systems and Intrusion Prevention Systems provide a hierarchical protection scheme.
The typical BOC security solution usually relies on issuing access badges to authorized individuals to allow them inside the building. Once inside a facility, security is a matter of trust. Hey, it’s not perfect, but at least we have an employee, a face, and a great deal of control over access.
A layered approach
While there are many differences between broadcast engineering and IT technologies, we must admit that we’re moving into a future of coexistence and integration, of building converged technology infrastructures.
A modern broadcast infrastructure, one that supports compressed media, can be characterized by three tiers: an Essence Layer, Media Network Layer and an Applications Layer.
The Essence Layer is the actual video, audio, graphics or other program elements. It can arrive or depart via satellite, fiber, cable, phone lines or over-the-air. Essence is also created by a graphics department, or from a studio control room. Signals could be HDTV, SDI, DV, analog video, audio or CC info. Essence is distributed throughout the facility on coaxial or other types of cable.
With ingest and subsequent compression of this essence, media networks has become a primary method of essence file distribution throughout the facility. Servers are replacing VTRs, and LAN file transfers are augmenting cable distribution. Content is instantly accessible to those who need it.
The Application Layer is the software that efficiently and reliably controls resources and distribution of essence in day-to-day operations.
But let us not forget that without proper security measures, wrapped around this three-tier edifice, a BOC is at risk of experiencing all the problems Internet worms and viruses can inflict. The first lesson for a 21st century broadcast engineer to learn is that IT technologies in a BOC are nothing like a home PC network. We are faced with the challenge of developing a new engineering discipline. Media systems engineering is now the child of the marriage of broadcast engineering an information technology.
The “Transition to Digital” newsletter
In the subsequent articles, this newsletter will describe the components needed to build this new infrastructure: one based on both IT and broadcast standards. The key will be to show how engineers can leverage commodity IT technology to improve traditional broadcast/production facilities and workflow. The next newsletter will discuss the organizational impact of the transition to digital and of program management when traditional broadcast engineering and IT technologies merge. Often times, it’s easer to get the equipment to work than to get the people to work with the equipment.
Reference Articles
If you’d like to learn more about the integration of Information Technologies in a Broadcast Operation Center, consider the follow resources.
“Digital data infrastructures in post-production”
http://broadcastengineering.com/mag/broadcasting_troubleshooting_digital_video
“The accidental system administrator”
http://broadcastengineering.com/mag/broadcasting_accidental_system_administrator
“INTERNET + DTV BROADCASTING = UN-TV”
www.nab.org/research/Reports/DTV-Internet.asp
NIST GCR 03-859, ”Economic Impact of the Advanced Technology Program's HDTV Joint Venture”
www.atp.nist.gov/eao/gcr03-859/chapt1.htm
