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HD for news

Many people in the broadcast industry speculated that HD news wouldn't be successful. Pundits predicted that HD might reach the news studio, but bandwidth constraints would keep it from ever reaching the field. Others questioned the motivation for HD news. They predicted that since HD without surround sound would not sell, news would likely never convert. Some people thought the cost for HDTV acquisition equipment would never be cheap enough for news departments. Indeed, 10 years ago, an HD camcorder at prices compatible with news acquisition was a long ways off. Editing was expensive, and with limited hard disk storage, the thought of nonlinear news editing in HD was mostly a pipe dream.

That was then, and reality and the passage of nearly a decade since HD approached real-world implementation has put clarity to many of the concerns. The early adopters of HD technology for news blazed a trail.

Early implementations sometimes simply followed studio shots using a cuts-only switcher slaved to the main 4:3 SD production switcher. As a result, production values were predictably low, giving the naysayers a case against HD news. But today, the cost of hardware has dropped so dramatically that HD news is fast becoming a necessity in markets where competition has always driven investment in news hardware. Without that competition, how many Doppler radar systems or news helicopters would there be?

Latency issues

Today the market is grappling with the differences that HD brings rather than fighting implementation costs and the lack of suitable hardware.

Make no mistake about it, HD brings challenges that are materially different from those SD has conquered or never had in the first place. For example, look at the latency (delay) in ENG links. Analog links have essentially no latency at all. A digital microwave link will likely have much less than one frame of latency. For many years, HD encoders created significant latency, especially when bandwidth was restricted. Today, however, there are systems in several frequency bands that use COFDM modulation and low latency codecs, which feature latency as low as one frame (encode only), and typically a similar latency in decode. While not instantaneous, a system latency of two frames is acceptable in almost any application.

There is a second place where latency in HD, indeed in all DTV, is an issue. If a field reporter is doing a live link with audio received from the off-air channel, the received audio could be as much as several seconds late. Obviously, that doesn't work for live two-way interviews! With analog, it is not unusual to use cueing channels transmitted with the main signal. With HD local news, cell phones or other means have to suffice for IFB return circuits, unless a low latency return microwave link is employed.

The cost of HD

The economic equation that delayed the development of local HD news has radically changed due to the development of HDV and other technologies. These new technologies make HD news hardly more expensive than SD was a couple of years ago. Issues like expensive storage networks are no longer dragging down the switch to HD. Last year, for the first time, the cost of disk memory dropped below that of videotape for equivalent bandwidth. Cameras can record HD content at around 20Mb, so it is much easier to justify the storage bandwidth HD requires.

At the same time, the cost of HD-capable nonlinear edit systems has dropped considerably. It is now possible for consumers to shoot and edit HD content with features broadcasters would have killed to have less than a decade ago. Terabyte laptops are not far off, and memory recording cameras can now capture about 80 minutes without moving parts. New codecs shared between consumer and professional products, such as AVCHD, further decrease the cost of HD storage.

Set design challenges

HD does present some challenges that are not likely to disappear any time soon. One is the need to spend more money dressing a news set for HD production.

Both the resolution of the cameras and the wide aspect ratio beg for new thinking on set design and lighting. High contrast lighting may challenge the physical appearance of some journalists with cameras that have twice the spatial resolution of SD. Compact fluorescent lighting can help by the nature of the extended sources used, creating a more pleasing and natural image.

Sets must be carefully thought through. For example, depth of field is not the same with HD cameras as with SD. To get the same effect on the background in a set, the camera shooting distance may need to be adjusted.

Handling 5.1 audio

It is safe to say that many broadcasters have not switched to stereo production, and 5.1 surround seems like an impossibility. Frankly, it probably is inappropriate for news content. But the question becomes how to handle the audio in the entire broadcast chain so the home receiver is not switching modes, with almost certain issues for home listeners. Many have chosen to use synthesized surround sound as the house standard. There are now devices available that can pass 5.1 when it is present and create a good synthetic image when it is not. Doing so allows the home receiver to remain locked to a surround signal, preventing receiver unlock.

Removing the final barrier

Lastly, the cost of HD infrastructure is rapidly reaching parity with SD, removing the last barrier to HD implementation. Today, equivalent systems are 10 percent to 20 percent more expensive in HD than SD, with only true HD-quality lenses likely to remain higher in cost for the foreseeable future.

A few years ago, critical elements in the production chain, such as production switchers, were much more expensive. Now models with good feature sets are available at below the cost of some SD-only products. It seems likely that in the next few years, manufacturers will cease to make SD hardware.

John Luff is a broadcast technology consultant.

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