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tech spotlight: ENG
MSI, HARMONIC TEAM ON DIGITAL IFB SYSTEM
TVNEWSDAY, Mar. 27, 7:40 AM ET
The two vendors have come up with a one-way digital system for cueing reporters in the field. It's designed to replace the analog system stations will lose in February when they shut down analog transmitters.
By Arthur Greenwald
When stations pull the plug on their analog transmitters next February, they’ll abandon more than their current broadcast signal. Most will also ditch their chief means of cueing reporters in the field—the analog-based audio link known as IFB.
“We were about to lose a very valuable tool in the field and nobody was applying themselves to solve the problem,” says Martin Faubell, VP of engineering for Hearst-Argyle Television.
Nobody, that is, except Eric Small, chief technology officer, of Somerset, N.J.-based Modulation Sciences, whose ProChannel is the de facto industry standard for analog IFB systems.The ProChannel transmits IFB audio using a small portion of a station’s main analog channel.
IFB stands for Interruptible Fold-Back, a BBC term for cueing talent, frequently corrupted as Interruptible Feed-Back in the U.S. IFB audio is “interruptible” both in the sense that the talent’s own voice can be subtracted from the mix (“mix minus”) and that the director can break in as needed to add spoken cues or instructions.
Ten years ago, the Society of Broadcast Engineers anticipated the need for a replacement IFB system in the post-analog world so it persuaded the FCC to set aside part of the 2 GHz BAS microwave band for a Data Return Link.
But long delays in the Sprint Nextel reimbursement program for converting the band from analog to digital has pushed back the availability of DRL.
Many stations presumed they could make do until DRL with ordinary cell phones. But that’s wishful thinking, according to Faubell. “It’s not a bad solution until there’s a major news event when reliability is critical. Unfortunately those are the very same times when ordinary users tie up the public networks.”
During emergencies, adds Small, media access is further restricted by FCC rules that encourage cellular carriers to provide priority to national security and emergency services personnel.
Knowing that his ProChannel receivers would expire with the analog spectrum, Small got an early start designing a system for feeding audio cues over a station’s digital channel and came up with Digital PRO.
Like the current system, Digital PRO includes no return path. For that, the station and the control room rely on the same microphone audio viewers will hear during the live shot (typically transmitted via microwave.)
As a longtime Modulation Science customer, Faubell was relieved that it was working on the digital solution, but he also knew that it had to overcome a big problem—latency, the audio delay caused by the digital encoding process. In the field, even a slight pause before a cue guarantees an agonizing moment of dead air.
Faubell felt he could help with a little high-tech matchmaking. “We needed a rugged product with specialized software,” he says.
At his suggestion, Modulation Sciences joined forces with Harmonic Inc.in Sunnyvale, Calif., known for its fast encoders.
The marriage worked. “Eric fit the bill because of his history [with IFB]” says Faubell. “It was fun to watch the pairing of smart guys applying themselves on both ends of the equation. We’ve gone quickly from promise to working prototypes.”
Almost at once, they reduced latency to about half a second by coupling the Digital PRO with the Harmonic’s DiviCom MV-45 video encoder—comparable to the quarter-second delay of a “one-hop” satellite transmission.
While Harmonic’s MV-45 could probably satisfy many station’s IFB requirements as is, it would be costly and inefficient to use a video processor just to encode a small amount of audio, says Harmonic’s Joel Wilhite. “We’re building a streamlined audio-only DiviCom encoder and writing new codecs to further improve latency.”
How much further? Quite a lot, according to some who’ve witnessed recent trials. For now, the two companies prefer not to specify until the NAB Show when visitors to the Harmonics booth will be able to test the prototype Digital PRO for themselves, using a mike and headphones.
“The new Harmonic encoder will offer stand-alone ASI-capable output in a chassis that’s compatible with any manufacturer’s system that accepts ASI,” says Wilhite.
Eric Small expects to sell his Digital PRO IFB receiver for the same price as the present PRO-3 analog system: $3,950. Harmonic will announce its encoder pricing at NAB. Wilhite expects there will be “a rate card with different pricing depending on the number of channels you need.”
At that time, the companies will also announce final features and delivery dates, probably the early third quarter of this year.
There is still work to be done.
For one thing, says Faubell, stations were looking forward to some of the features inherent in DRL. “Stations had come to expect a two-way transmission. The lack of a return path is an issue that at first discouraged people from pursuing [the Digital PRO] solution.”
But, fortunately, adds Faubell, field reporters still have numerous options for talking back to the control room. In addition to the live open mike and cell phones, he says, “there’s EVDO and 3G wireless laptop cards, and WiMax is coming along.”
None of these options, however, are much help to journalists reporting from moving aircraft. Consumer wireless networks are programmed to terminate calls whose signals “light up” too many cell towers—a sure sign the signals are originating from the air, which is illegal.
What’s more, movement and Doppler effects make it difficult for an aircraft in motion to receive a station’s digital signal, including the IFB audio.
Small considers this just one more item on his to-do list. “We expect our [mobile reception] solution to be ready within six to nine months after Digital PRO first ships,” says Small.
In other words, just in time for the February 2009 analog cut-off.
Contributing Editor Arthur Greenwald writes occasionally about technology and new media, but his main gig is his Market Share column about station promotions. It appears almost magically every Monday.
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