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01.10.2006
Originally featured on BroadcastEngineering.com
Playout automation 101

Playout automation used to mean a playlist running a cart machine. The prime function was to play commercials breaks and interstitials. Now that the video server has replaced the cart machine, automation has evolved and become a core part of master control.

Reliable playout of commercials is still the No. 1 reason why broadcasters adopt automation. Two developments are now making automation essential rather than an adjunct to a transmission center. First, stations and networks are moving away from videotape for the distribution of programs and spots to the use of files. That way they can realize cost savings from leveraging data networks and information technology. Automation becomes easier in a file-based environment; media no longer has to be physically moved around from library to cart. Spot delivery over IP networks has now become commonplace.

The second development stems from digital broadcasting. Stations are moving from a single channel to multicasting and taking advantage of the flexibility that a digital multiplex offers. Multicasting often means repeat plays of programs, another reason to move from tape to servers for all playout, not just spots and interstitials.

Automation is core to the management of a station’s revenue stream. If commercial spots do not air at the scheduled time, in their entirety and error free, then the revenue is at risk. On a recent tour around a transmission center, the guide dismissed playout automation as “just a playlist” and as being much simpler than the manufacturers make it. It wasn’t clear if this was an understatement or just lack of knowledge.

Automation is a playlist, but it has to meet some very tight specifications. For a simple movie channel the requirement is not very demanding, but for a general network with a mix of programming it can become very complex. The principle of an automation system is to play a sequence of events. For each event, the content must be made available, cued and played to air at the scheduled time.

Some form of media management system integrated with the automation can be used to make the content available at the appointed date. This could be through data links to a digital asset management system. The media management system will most likely control the ingest of new content and manage delivery to the correct playout server. It should also warn operators in advance of missing material so that remedial action can be taken well before the scheduled airtime.

It goes without saying that a system should be frame accurate. It is not possible to play out commercials back to back without frame accuracy. A clipped commercial can mean a make-good. Tape-based playout relies on the VTR being cued and pre-rolled to get frame accurate playout. Even with file-based systems, there can be considerable latency. Any compressed video must be decoded, a process that takes tens of frames. Decoders can be pre-charged, but all such latencies have to be allowed for when the playlist is running multiple devices in synchronism.

Although many cable and satellite channels use a simple playlist, prime channels have much more complex demands. With a mix of pre-recorded and live programs, news, interstitials and commercials, the prime channel demands a well-featured automation system. Many networks have dynamic scheduling to cope with breaking news and live events. Sporting events are a good example of this because vagaries of the weather can affect timings. There are well-established scheduling techniques, such as the provision of alternate programming. But this pool of live or recorded content, with varying start and stop times, must all be wrapped seamlessly around the commercial breaks. A station may be opting in and out of a network feed. There may be regional breakaways at different parts of the day. It all makes for a multilayered timeline.

In the multichannel world, broadcasters look to channel branding to help their product stand out from the crowd. This has led to complex interstitials, with DVE squeezebacks, and increased use of graphic sequences. Again, a reason for automation is to run all the devices contributing to the on-air look.

Even the most reliable systems can fail, and every station has a fallback. It could be a fault caption, and then could run the standby tape. With automation it becomes easier to design systems that can fail gracefully and need less operator intervention to manage the situation. In a multichannel world the transmission controller may have 10 or more channels to supervise and the automation becomes a valuable aid to managing a crisis.

The principal means to cope with system failure is to provide redundant facilities. It may be a complete mirror or at a lower cost an N+1 redundant system. The configuration of a playout center with soft failure is a compromise between the service level and cost.

Playout automation is evolving from the simple playlist to an essential part of managing the channel brand and the complexities of multicasting. It also forms a key component in the management of file-based transmission as videotape is relegated to an archive medium.

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