Skip to main content

NBC-U Preps for AFD

ALBUQUERQUE, NM There's been a lot of buzz about Active Format Description (AFD) during the past couple of years, but with so many other issues to be resolved in getting ready for next February's "D" Day, many broadcasters have been sidestepping this DTV element, allowing it to languish until someone complains about the way pictures are being displayed. That is, until recently.

NBC-Universal has decided to take a proactive stance and roll out full blown AFD implementation in a representative test market—Albuquerque, N.M. (ranked 45th in U.S. DMAs). Actually the extent of the testing area went well beyond this city of nearly half a million people: KOB-TV, the Albuquerque NBC, appears on 86 cable systems across America's fifth geographically largest state, and spills well over the borders into neighboring states via a network of translators. Its signals also are relayed by DirecTV and Dish Network satellite transponders.

(click thumbnail)
The NBC-Universal/KOB-TV signal path
As such, NBC-Universal officials decided that Albuquerque might be an ideal place for a trial run. After some preparation, the green flag was waved and New Mexico viewers watching the network serial "Days of Our Lives" on Sept. 24 got their first taste of what the world will be like with a system that automatically adjusts video content to their TV screens.

"We'd been planning an AFD market test for some time," said Clarence Hau, NBC-Universal's director of systems engineering and DTV transition project lead. "Albuquerque presented a great opportunity as it is representative of off-air, cable satellite and wide translator coverage. Our testing on Sept. 24 and 25 included KOB-TV's viewers across the state."

The second day of the AFD trial extended into NBC's "Today Show" and the next chapter of "Days of Our Lives."


According to Sean Anker, director of engineering and production at KOB-TV, the test was successful.

"Feedback from the CATV guys was great," Anker said. "Everybody liked to see program providers have control [of the content] to see that it was presented properly. As to our viewers, if you don't hear anything, then everything is great. Actually, we really didn't have any feedback concerning the implementation."

Anker said that the station had done its own tests with several representative set-top boxes, including a new Zenith model and an early version Digital Stream.

Hanno Basse, DirecTV's vice president of system engineering was involved in the New Mexico trial run and also was happy with the way things went.

"The Albuquerque test worked really well for us," he said. "We have a plan to roll this out around the country."

Basse reported, however, that even though the recent venture with KOB-TV was satisfactory, there is still quite a bit of work ahead for the satellite program provider.

"We've been working with a lot of stations around the country for the last eight months or so," he said. "One of the problems we've found is an absence of AFD technology. We basically have to come to an agreement with each station—shadow box or 4:3 center cut. A fixed [presentation] environment is not really that satisfactory. We've also got some other station groups looking into AFD technology."

Basse said that DirecTV is in the process of installing digital demodulators to replace analog units in DMAs nationwide. The units chosen for the conversion are set up to detect and process AFD commands sent by broadcasters.

"Our digital receivers will recognize the AFD commands and switch the SD output between center cut and letterbox," Basse said.


Hau said that just before the Sept. 24 trial, "we made preparations to feed KOB-TV a standard SMPTE 292 bitstream that included AFD packets. We're now delivering our programming to KOB-TV and most other NBC affiliates in that format."

From that standpoint, it was a very standard implementation, according to Anker.

"We just run it through our switcher," he said. "The only special thing that we did was to install one piece of equipment in order to run some tests and make sure that everything was working properly. We also had to do a software upgrade to an older Tandberg encoder we have. Once that was accomplished everything was very simple."

Anker added that video containing AFD information was sent to the station's digital transmitter on two-mile high Sandia Crest. This off-air DTV signal with AFD was received by the Comcast headend in Albuquerque—the local signal collection facility for DirecTV and Dish Network. It also went to translator locations where it was relayed onward to other translators sprinkled around the state. In each of these locations, AFD-ready downconversion receivers provided a properly formatted SD signal that was distributed to viewers across the state.


All parties in the Albuquerque trial hope that their work will springboard into a nationwide effort to ensure that delivered content properly fits the display device. To that end they are committed to full implementation as soon as possible.

"From our standpoint, NBC is getting ready to expand delivery throughout the rest of the HD backhaul network," said Anker. "We will be putting it on the air full time by mid-October. We've installed a Miranda MMX-1801 AFD and metadata inserter so that all of our upconverted material will have an AFD identifier all of the time. We're very pleased with the results."

"For us this was a test," said Basse. "We also need to take the results and start rolling out the technology across our network. It doesn't exist ubiquitously."

James E. O’Neal has more than 50 years of experience in the broadcast arena, serving for nearly 37 years as a television broadcast engineer and, following his retirement from that field in 2005, moving into journalism as technology editor for TV Technology for almost the next decade. He continues to provide content for this publication, as well as sister publication Radio World, and others.  He authored the chapter on HF shortwave radio for the 11th Edition of the NAB Engineering Handbook, and serves as editor-in-chief of the IEEE’s Broadcast Technology publication, and as associate editor of the SMPTE Motion Imaging Journal. He is a SMPTE Life Fellow, and a Life Member of the IEEE and the SBE.