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10.09.2007
Originally featured on BroadcastEngineering.com
Straddling the HD, SD line requires a strategy

When HD Technology Update spoke two weeks ago with KMBC-TV director of engineering Jerry Agresti about the Kansas City, MO, station’s launch of HD local newscasts, he identified the number of HD and SD conversions needed to serve both audiences as a bit of surprise. (See KMBC-TV launches HD local news from new broadcast center.)

Agresti’s observation echoed comments Cordillera Communications director of engineering Andrew Suk made to HD Technology Update in the spring when talking about the launch of local HD newscasts at the broadcast group’s stations in Tucson, AZ, and Lexington, KY.

The similarity prompted HD Technology Update to speak with Darren Burdow, director of sales at Ross Video, about managing the HD-to-SD and SD-to-HD conversions needed to produce a local newscast for both viewing audiences. Ross Video has an extensive history of offering multidefinition production switchers and in the spring rolled out a multidefinition server.

In upcoming weeks, HD Technology Update will explore the topic further with insight from various perspectives.

HD Technology Update: Can you briefly describe where Ross Video stands today with its multidefinition production switchers?

Darren Budrow: Our sixth generation of production switchers, which is Vision, builds on the Synergy multidefinition platform. The Vision family of control panels connects up with the MD/X rack frame solution, which is our multidefinition hardware platform.

Learning from the 4:3, 16:9 conundrum and almost a decade of being able to integrate both 4:3 and 16:9 signals in our production switchers, Ross Video was one of the first to deliver an in-switcher solution for simultaneous multiple aspect ratio productions.

HD Technology Update: What’s your perspective on the best way to handle multiple aspect ratios and a mix of SD and HD sources?

Darren Budrow: Looking forward into HD, we wanted to make sure our platform would have a truly seamless capability of combining SD and HD and outputting a production that could be multiformat as well. So, we can accept a mix of formats and also produce in a number of different formats.

The switcher itself, that technology, we keep as HD (or SD). We then use dynamic path finding to external up/down/crossconverters to do all of the format conversion between SD and HD sources.

HD Technology Update: So, your approach is not building converters into the switcher?

Darren Budrow: There are two choices here. You can either integrate those up/down/crossconverters and resizing directly in the switcher, or you can have them external. We decided to go external and this is something that has been a Ross Video engineering philosophy for generations of our production switchers now.

HD Technology Update: Why did you choose not to integrate the converters in the switcher?

Darren Budrow: By keeping those external, as the facility’s requirements change and they get more HD sources, they are going to be able to free up some of those pieces of hardware — those up/down/crossconverters. If they were built into the switcher, it’s a sunk cost. There's nothing you can do about it — you can’t use them elsewhere.

If they are external pieces of hardware, they continue to have value. They can be repurposed within the facility. They can be sent out to the OB van or handed down to another studio or station in the group — they have value.

This has been our main engineering focus when we approach next-generation technology — to make sure that it can straddle this SD to HD transition and allow facilities to change and grow with us down the road.

HD Technology Update: So, multidefinition, as Ross Video uses the term, refers to the switcher handling any of a number of different standards, but not multiple standards internally at the same time.

Darren Budrow: The switcher is SD or HD, and it’s any of the formats — NTSC or PAL for your SD-SDI. When you get into HD, it could be 720 or 1080 and 24Hz, 50Hz or 60Hz, depending on the facility’s format of choice. So, you have all of those formats that the switcher can switch natively.

Now, what happens if you have 20 sources, 10 of them HD and 10 SD? Our solution let’s you set the switcher to be HD and convert those SD devices to HD. We use a small group of external converters and we let the switcher reroute signals behind the scenes to these converters. It’s elegant so the operator sitting at the production switcher doesn’t need to know if it's SD or HD. All they are doing is listening to the director say: “Camera two, take. Camera three, dissolve. Roll VTR Blue.” There's no concern about whether that's SD or HD. All this happens completely behind-the-scenes.

HD Technology Update: How so?

Darren Budrow: Just using a mathematical formula, we can figure out the worst-case scenario — the maximum number of converters you would actually need in any one production. We can now reduce the number of converters you would need to purchase and let the switcher handle the entire path finding dynamically for the operation.

Tell us what you think!
HDTU invites response from our readers. Please submit your comments to editor@broadcastengineering.com. We'll follow up with your comments in an upcoming issue.



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