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Sigma Electronics OctaStream

Mar 1, 2006 12:00 PM, By John Stevens, Encore Hollywood

Keeping Synch in the Facility

Encore Hollywood is busy. We work on feature films, episodic and long-form television, music videos, and commercials. Our work varies from specific services — such as telecine or visual effects — to complete post, from dailies to the finished master.

In Hollywood, “fixing it in post” is still the name of the game. We never say, “We can't do it.” Instead we ask, “What are we going to need to do it?”

One critical issue: Assuring the perfect synchronization of audio and video in all stages of our operation. In one form or another, out-of-synch AV situations are spotted several times a week, usually because a technical error occurred in the production phase.

There are three AV synch issues that we have to constantly solve on the fly. The first is ensuring that telecines and peripherals, such as color correction gear, are in synch. The second is ensuring that audio tracks on completed masters match the lineups required by individual broadcasters. There is no universal standard specifying that order. Production companies may record their audio tracks in any combination they choose, but multiple domestic and/or foreign broadcasters may each have different track setups in mind. We have to be constantly aware of assigning Dolby 5.1 Surround Sound to the needs of various broadcasters.

The third is an ongoing problem in editing suites equipped with plasma monitors. How's that? Most sets we see have built-in buffers that create their own video delay of two to three frames. In an Autodesk Fire edit bay or a Spirit telecine suite, someone can rock and roll audio to synch with video and be perfectly on course for the program output, but the plasma broadcast monitor viewed by the client in the client area, usually a 42in. unit or larger, can be wholly out of phase because of its internal buffering. The same problem often affects projection monitors used in client areas.

The bottom line: The video viewed in the suite needs different AV synchronization than the shipping copy. It's essentially a problem we solve for visiting clients who must have spot-on synchronization without knowing or understanding that there is a synch problem at all.

More than a year ago, I started looking for a simple but elegant solution to these interlocking issues. Like those in other facilities, I could solve the synch issues with small in-suite audio mixers, but the solution was worse than the cure. They did the job, but were often too difficult to operate and took up far more real estate than the function they solved warranted. We also had some proprietary black box solutions, but our operators weren't fond of either solution.

I put out the word to several manufacturers about our needs. Sigma Electronics, one of the veteran equipment companies in the broadcast field, came up with a solution. Its OctaStream AES audio management system was a close match for what we needed.

But we needed a different front end. Instead of thinking of this unit as a mixer, implying realtime control over all parameters and a knob for every function, we needed what I've called a “programmable summing.” For example, the user panel I wanted would not be set up to do audio sweetening, but would instead give us the flexibility to mix and exchange audio channels, move channels 1-3 to the left, and put 2-4 on the right — I wanted that level of flexibility.

My list continued: I also needed the ability to change the order in realtime, and I wanted programmable delays built into the unit. Finally, it would be ideal to be able to store snapshots of all of the settings for easy recall.

The solution Sigma provided uses a 1RU control panel that mounts in the production suite. It's attached to a self-powered 2RU machine room unit containing up to eight delay modules, mixer/router modules, and an optional sample rate converter.

An intuitive user control panel is the heart of the system. I developed the concept, while Sigma supplied all the real-world details, down to the best button locations. The LED-lit panel consists of a menu-driven control system, eight fixed-function buttons, and eight redefinable function buttons.

Eight configurations can be stored for recall, with Ethernet allowing you to add extension panels. Now, our editors can directly manipulate up to eight audio channels in their suites. It lets them synch, set sequencing, and store presets for each version of each show.

We also use the system in our dub center. This can get tricky because productions want their audio done one way, and the networks want it done another way. For example, a network may want a wild track on track three and Dolby 5.1 on another. You might not recognize the track layouts between production and delivery. OctaStream lets us select the required channel order; it compensates for any AV processing in the signal path.

Working with another Encore engineer, we came up with a minimalist design solution that did what our facility needed it to do. Sigma turned things around quickly, producing the working unit within six weeks of our initial conversation.

We're currently using OctaStream in multiple telecine and Autodesk Fire bays. Eventually, we'll install them in our Avid DS suites too. This is a solution that works for us.

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John Stevens is chief engineer at Encore Hollywood. Encore Hollywood, an Ascent Media company, is a full-service postproduction facility. Encore specializes in television episodics, digital intermediates for feature film, commercials, music videos, and visual effects. Its clients include HBO (including all three seasons of Deadwood), Showtime, Warner Bros., ESPN, and many others. For more information, visit www.encorevideo.com or call (323) 466-7663.

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