Q+A CENTER

ROUNDTABLE

Digital Broadcasting Implementation and Compression:
A Reality Check

by Barry Mazor

March 2002

If we went back to the broadcasters' situation as it looked "two to three NAB's ago," to use the way the broadcast engineering contingent often looks at these matters, it was that federal demands to move ahead towards digital TV transmission were in place, various interactive digital information and image streams were looking like hot new revenue sources, and the key practical question was whether to move towards "total-MPEG" compression-based formats for equipment in stages or at once—and content.

There was considerable discussion of the practical issues involved in these pages at the time, including a pointed piece by the articulate technical executive from Panasonic, Phil Livingston.

Since then, there have been hundreds of stations have gone digital, built up their production LANs and WANs, and slowly but surely turned toward general high-definition production, too. We've seen the crash of the 'Net bubble, issues with cable enabling of HD business, and an advertising recession. So what has become of the TV implementation models, especially as they concern the crucial issue of compression, in the face of so much change? How has this all been working out, in fact—as users are making engineering choices and implementing systems? We checked back with Phil Livingston for some timely comment.

THE SITUATION

Barry Mazor, Advanced Imaging: First of all, Phil, do you agree with the general picture we've just painted?

Phil Livingston, Panasonic: It is, indeed, important to remember--and too easy to forget--that the Federal Communications Commission mandated a migration to DTV, not HDTV per se. Broadcasters may transmit one or more HD or SD streams, with ancillary (related) data, or unrelated (opportunistic) data. PBS may be the best example of choices being made in this regard, where daytime educational services can be 4 (nominally) SD program streams, and at night a single high-quality HD offering is what viewers want. Marilyn Mohrman-Gillis, VP for Policy & Legal Affairs at the Association of Public Television Stations, just spoke eloquently about this at the 15th DTV Update held by MSTV in Washington, in February.