IPTV Among First to Install ACE

Understanding the driving forces behind PBS's new automation System

JOHNSTON, IOWA: This month's journal is the beginning of a series on a very important project that will be taking place at IPTV-the implementation of the PBS ACE system for master control.

I have been asked several times to explain to our board of directors the concept of the ACE system and how it fits in at IPTV. To understand the concept of ACE, it is helpful to know some of the underlying drivers that led to its creation.

Probably the primary driver for the creation of ACE is the planned migration of the PBS content-delivery system from video and audio to a file delivery system. Since the leases for the nine transponders used in the current satellite delivery expire in October 2006, and given the inherent inefficiencies in the system and the advances made in digital compression, rethinking the delivery model from a real-time audio/video delivery service to a nonreal-time file transfer service just made sense.

Unlike our commercial brethren, PBS is not a network that we join, but a service we purchase with dues. As such, the PBS member stations are a very independent group with a great deal of flexibility in determining when to air PBS-supplied content. Very little content from PBS is aired live from the feed; the majority is shuffled and aired when the local station determines it has the best potential audience. Much of the content will be aired multiple times during the course of a week. This can add a lot of complexity at both PBS and stations.


Thus, out of these factors and a few others, the next-generation interconnect system (NGIS) was born. NGIS takes advantage of the improved digital compression and IT-based technologies to create a hybrid delivery system that includes satellite- and terrestrial-based connections as well as local station edge servers with automation to request and store content. Since most PBS content is delivered weeks in advance of airing, this allows the network operations center to deliver content to the stations using whatever delivery method is appropriate, and to store the content on the local station edge server. If the station plans on airing the content multiple times, the material is merely kept on the edge server and is available when needed. Content for the most part is fed once to all stations and managed locally on the edge server.


The next logical layer at the station level is ACE. Originally called the enhanced interconnect optimization project, or EIOP, the idea is essentially to transform the edge server from a PBS store-and-forward server to an all-station content playback server. Integrate this with automation and traffic systems for both local and network content and add a master control system and exception monitoring-now the local operation can be streamlined.

I first heard about this concept on a conference call. I had been on the PBS engineering committee for about two months. I was at our transmitter site in Fort Dodge, sitting in an SUV in a cornfield, so my mind was pretty open to conceptualizing.

Because of budget constraints, IPTV had been unable to proceed with any of our planned DTV conversion at the studios. What I heard being described was exactly what we needed, and since we had been handcuffed financially, we did not have to deal with any thoughts of how we make this fit in our DTV structure. I offered to implement the system at IPTV as soon as it was available.


There has been unrest within the PBS station community over the ACE concept. Not that the concept itself is flawed, but how it will benefit stations has been called into question. One of the potential benefits, which has been overstated in my view, is the potential for personnel reduction. In the initial concept and subsequent refinements, PBS presented the ACE as a potential walk-away master control operation. Using Miranda Probes and a backhaul from the station to PBS headquarters in Alexandria, Va., the PBS folks propose to take over monitoring master control from their NOC and dealing with problems by trouble ticketing from the NOC. The idea appears to be that the operator sitting in master control for an eight-hour shift would go away.

I haven't worked in a station since 1990 where the MC operator sat at the console and watched TV. In the real world, he or she is dubbing spots, pulling tapes, ingesting content, setting up satellite feeds and doing any number of tasks that are still going to happen for some time to come.

So I don't see ACE reducing personnel. I do see it making the job of MC more manageable, especially in an environment like IPTV, where we will be multicasting to nine transmitter sites throughout Iowa.

I briefly mentioned exception monitoring-I don't want to minimize that this is a very different concept than most broadcasters are used to, especially at the general manager level. From an engineering point of view, I'd say most stations have been forced to morph into exception monitoring.

We have all had our staffs reduced and are doing more with fewer people. As that change has happened, the people who are doing more have begun to operate on the assumption that if the alarm isn't ringing, then there's no problem. Therefore, on-air blackness typically won't set off any alarms unless it happens to be in the middle of a program and the GM happens to be watching and wants to know where in the ^%$#^% the MC operator is.

Many stations are doing exception monitoring, but they are doing it without a net, and in some cases without the monitoring.

For exception monitoring to work, all the details have to be right on the front-end; automated systems typically do not deal well with ambiguity. Metadata has to be correct from beginning to end. There have to be failover systems, backup paths and myriad intelligent forethought to deal with the truly unexpected failures. Sales that get put off until the last minute cannot be considered normal operation and therefore accommodated.

So for exception monitoring to work, it has to be embraced at all levels of the operation.


In the Digital Journal in the July 26, 2000 issue of TV Technology, I described my concept of the digital master control using the cockpit concept of a modern jet aircraft. In the fly-by-wire world of high-performance jets, there are too many systems for a pilot or two pilots to effectively monitor and control. The control of the aircraft is therefore under the command of computers.

In jets, there are a couple of multifunction displays (MFDs) that automatically show critical operating parameters and switch to display alarm conditions and correction commands. In the majority of cases, the display is informational because the automation should have already made the appropriate corrective actions.

The idea is to ensure that the operation continues as smoothly as possible, while making sure that the operator knows about the problem.

This is one of the fundamental elements of the ACE system.

I had hoped to be able to offer more detail about the nuts and bolts of the implementation of ACE at IPTV. Unfortunately, since our preliminary meeting with PBS engineering, we have not seen a lot of information on progress. PBS of course was busy with preparation for the PBS engineering conference that took place just before NAB, and then NAB as well. We have put together a preliminary project schedule that will have us operational on the ACE system by Dec. 7, 2004.

Another element that has been added to the mix is that PBS is now evaluating incorporating an archive system into the ACE project. Although this is certainly an important component, we don't see this as anything that will slow down our implementation plans.

Bill Hayes

Bill Hayes, director of engineering and technology for Iowa PBS, has been at the forefront of broadcast TV technology for 40 years, 23 of them at Iowa PBS. He’s served as president of IEEE’s Broadcast Technology Society, is a Partnership Board Member of the International Broadcasting Convention (IBC) and has contributed extensively to SMPTE and ATSC.  He is a recipient of Future's 2021 Tech Leadership Award.