In a recent Tech Spotlight, we focused on the importance of upgrading a station's equipment to broadcast the clients' high-definition commercials — and revising traffic department standards for accepting those ads in cost-effective digital file formats.

Of course there are real-world reasons that might delay your complete transition to high-def broadcasting. Even more frustrating are the technical obstacles that prevent viewers from seeing the full-quality results of your expensive technical improvements.

Perhaps the most vexing issue is aspect ratio, the protracted contest between the good, old-fashioned 4 x 3 analog picture and the widescreen 16 x 9 glory that is digital. Eventually, of course, digital will prevail. But until it does, stations and advertisers must wrestle with a long, awkward transition period, often deciding on a case-by-case basis how to format programs, and especially commercials.

As director of engineering of Hearst-Argyle's WTAE Pittsburgh, Dave Kasperek has been tackling these problems head on.

"Viewers expect the video to fill their screens vertically as well as horizontally," says Kasperek. "In fact, when viewers see letterboxed video on their 4 x 3 analog screen, they immediately complain."

That's why the vast majority of stations and cable and satellite systems elect to downconvert and "center-cut" the 16 x 9 digital image — that is, lopping off the sides of the widescreen picture to fill a 4 x 3 analog frame. But this, in turn, creates some additional challenges.

For one thing, logos and other graphics may be cut off if you don't remind advertisers and agencies often about the claustrophobic "safe title" area for center-cut video.

And some advertisers simply demand the widescreen look, even if that requires letterboxing on analog screens. That's fine if your equipment can accommodate exceptions. Otherwise you may lose the sale if the client is unwilling to remix the spot to meet your specifications.

But even this flexibility is an imperfect solution. Stations can't control how their signal will appear on analog TVs connected to DirecTV or Echostar. With so many local signals to feed, those satellite services began center-cutting video for analog sets over a year ago.

Kasperek believes that the ultimate solution is AFD — Active Format Description — the SMPTE technical standard that automatically switches the viewer's picture to the correct aspect ratio. Hearst-Argyle is just one of a coalition of broadcasters, producers and equipment manufacturers that are supporting the new standard.

The problem is, the AFD standard only works when recognized by an AFD-compliant device. "It may be years before we see AFD in widespread, let alone universal, use," says Kasperek.

That's why Hearst-Argyle figured it couldn't afford to wait. It has addressed aspect ratios and a host of other analog-digital conundrums by creating its own detailed plan for an HD commercial technical standard. "We'll share it with every client we have," Kasperek says. "This policy spells out to advertisers and production houses exactly how to get their HD spots on our stations."

The Hearst-Argyle system supports file-based transfer for HD commercials, which eliminates the need for expensive single-format tape machines — or even tapes. "We wanted to minimize media delivery costs for both the advertisers and broadcasters," Kasperek explains.

Kasperek expects WTAE and other Hearst-Argyle stations to "commence full HD spot capability in the very near future — certainly well before the end of 2008."

While Kasperek is confident in Hearst-Argyle's short-term solutions, and in the ultimate success of the AFD system, there remains one lingering "circumstance beyond our control." Nearly all converter boxes, cable boxes and digital TV's come with extensive manual controls that allow viewers to modify the picture in many ways.

"So despite our best efforts across all those industries," says Kasperek, "the viewers can ultimately screw up the intended video display any way they choose."

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We're pleased to note that Hearst-Argyle's HD commercial plan anticipated many of the recommendations we made in our last column, which generated some terrific reader response. Thanks especially to those who shared some additional observations:

Rich Paleski, director of broadcast operations and engineering for CBS's Philadelphia duopoly of KYW and WPSG, reminded us that "there are two broadcast formats for HD: 720P and 1080i. Sales and traffic departments should make sure that clients encode their files in the right format for the station." And because most broadcasters use one server for both HD and SD commercials, Paleski warns that many can't "deal with 5.1 channel surround sound on the SD portion of the plant. The HD audio standard should be stereo audio (one AES pair) until the industry is more mature."

And there is this insight from consultant and distinguished SMPTE Fellow, John Luff: "I agree that delivery needs to be electronic. Tape is essentially no longer viable. The problem is that playout servers cannot decode H.264, which is a much better way to compress HD content. We are currently stuck with MPEG2, MPHL or using a transcoder to convert files, which is less than optimum anyway."

Tech Spotlight, by TVNewsday Contributing Editor Arthur Greenwald and commercial producer-director  Glenn Przyborski tackles engineering issues every Thursday in TVNEWSDAY. Do you have a technical or engineering question you'd like to see answered? Send it to greenwald@tvnewsday.com.