Golden Eyes10/25/2009 11:15 AM Eastern
Watching a movie on an airplane used to drive Josh Derby nuts.
Derby, director of technology and standards at Discovery Communications, is one of a rarefied breed of video engineer known as a “golden eye”: an expert able to discern very slight imperfections in picture quality.
His job at Discovery once involved watching programming for more than 10 hours a day to ensure it looked precisely perfect. Regular TV “would drive me insane,” he said. “I'd see every single little defect.” Derby concedes he still can't stop his eyes from defect-hunting: “My wife says it makes me intolerable to watch TV with.”
These days, golden eyes — the wine tasters of the TV industry — have become increasingly important as more subscribers connect ever-bigger television sets. Digital TV signals must be compressed for delivery over broadcast, cable, satellite or telco services, a process that often degrades quality, although those flaws (called “artifacts” in industry jargon) may be perceptible only to a golden eye.
Networks and their distribution partners aren't just aiming to please high-end audio-visual snobs. Suddenly, anyone with a 60-inch display can notice blurring or blockiness when it mars his or her favorite show.
“As the screens get larger and have higher contrast, defects that used to hide in the dark are now visible,” said NBC Universal senior vice president of technology strategy and standards Glenn Reitmeier. “They can come out of the dark and bite you.”
Moreover, HD is becoming the de facto standard for viewers, so they're growing accustomed to expecting a higher-quality video experience. As of June 2009, about 53% of U.S. households had a high-definition TV, compared with 35% in 2008 and 23% in 2007, according to an analysis by the Cable & Telecommunications Association for Marketing of consumer survey data from research firm Centris. Of those with HDTVs, 69% now subscribe to an HD programming service, compared with 56% a year earlier.
“You have to make sure the quality you work hard to develop in one place is what's delivered to the customer,” said Ron Gutman, chief technology officer and co-founder of Imagine Communications, a video-encoding systems vendor.
Equipment for monitoring video defects has grown increasingly sophisticated, but experts say nothing replaces a trained golden eye. Computers can analyze video and detect, say, macroblocking — a defect in which a grid-like pattern appears that is especially common in high-action content. But an automated system can't describe how that macroblocking affects overall picture quality.
“The human visual system is very, very complicated,” Derby said. “What we perceive as 'good' and 'bad' is hard to quantify.”
One of the biggest challenges in measuring video quality is that vision is an inherently subjective human experience. People see things differently depending on age, culture and even sex, because men are prone to having fewer color receptors in their eyes than women, said Sean McCarthy, a golden eye and fellow of the technical staff at Motorola.
“Everyone's visual experience is different,” said McCarthy, who previously studied the mechanics of vision as a bioengineering graduate student at the University of California at Berkeley.
Ultimately, the “best” way to encode video comes down to personal preferences, according to Matthew Goldman, vice president of technology for Tandberg Television's compression-systems group. While many golden eyes prefer to tune for sharper HDTV pictures, he noted, most consumers actually prefer “softer” high-definition video.
“It's an art,” Goldman said. “There's no right answer.”
Some are trying to put more science around the art. At the Comcast Media Center in Denver, for example, vice president of quality assurance Dave Higgins has established a “golden eye” program that scores and tracks video impairments of incoming programming feeds on an ongoing basis.
The CMC golden-eye team comprises 15 people who look primarily at HD services and evaluate video quality in six categories of digital defects on a scale of one to five (one being unwatchable and five being spectacular). Every week, the group gathers to validate that, say, a specific macroblocking defect counts as a two. “Where the true subjective analysis comes into play is, your two might be my three,” Higgins said, but his theory is that with more than a dozen golden eyes, the scores will average out.
As part of the program, which kicked off in January, the CMC every month has distributed scorecards to its programming partners, describing which areas looked really good, which didn't and where they ranked in relation to their peers. “They all want to be in the top third,” Higgins said. “The most important part of this program is to get results that are actionable” — to be able to assist a programmer in addressing issues that affect video quality before it arrives at the CMC.
In addition, Comcast is working to establish local golden-eye programs in at least two markets. “The goal is to spot-check us, and also to look at some of the local video that doesn't go through CMC,” Higgins said.
Not everyone is convinced the CMC's scorecards are the final word in video quality. “I applaud the fact they're trying to do that, but it's hard to do it objectively,” said Starz Entertainment senior vice president of programming operations Ray Milius. “How much did the guy sleep last night? Did they watch enough of the content to get a sense of it?”
While gauging video quality at a certain level can be a judgment call or a matter of personal taste, industry executives agree that golden eyes aren't born — they're made, the product of thousands of hours of training and experience.
One of the occupational hazards for these professionals, as Discovery's Derby attested to, is that regular TV-watching can become less enjoyable. Watching TV all day for a living may sound like every American kid's dream job, but golden eyes are trained to tune out the story in the program they're watching in order to concentrate on technical quality of the audio and video.
“I have people on staff who say everything that's on broadcast, cable and satellite is crap,” Milius said. “They believe nobody's giving enough bandwidth to our content.”
Derby, meanwhile, has grown more tolerant of video that is less than perfect, although he recently insisted his daughter upgrade to the Blu-ray disc of High School Musical 3 because of an early scene involving flashbulbs, an effect that's very difficult for video encoders to compress well.
The fatigue from staring at a screen for several hours straight also can take its toll. “Some of the hardest part of my job is telling someone they have to watch the same three-hour program for the fourth time,” said Steve Scheel, senior director of PBS's Media Operations Center in Arlington, Va. “That's when I think they're really earning their money.”
The “golden eye” appellation for video-quality engineers prefigures the 1995 James Bond movie of the same name (the title referred to a fictional Russian satellite-based weapon — and what Ian Fleming dubbed his vacation home in Jamaica). In fact, the term may date to the early era of television in the 1950s. Some say it goes back even further, to Hollywood's introduction of color movies, when “golden eyes” were in charge of maintaining color consistency across different film stock.
In the days of analog TV, golden eyes correlated specific kinds of interference with specific characteristics of distortions. “To be honest, it was a lot easier in the days of two-inch quad tape — the impairments used to be much more obvious,” Scheel said.
By comparison, defects in digital video are more subtle and may originate at several different points in the distribution chain. “There are a whole new set of artifacts that can be introduced to the signal during its creation and distribution,” NBCU's Reitmeier said.
For digital broadcast and cable TV programming, it's critical to start with very high-quality video, because encoding issues can concatenate down the line when the signal is re-encoded or otherwise modified further down the distribution chain.
The cliché is “garbage in, garbage out”: If the copy of a film has dirt or smudges, those will show up as noise in the encoded digital version, Milius said. He estimated that about 30% of the material sent to Starz is returned to a studio or production house for various reasons.
“The better quality we start out with, the better quality will come out when our distributors step on it,” he said.
Once the video reaches the headends and is on its way to customers' homes, cable operators are less concerned about fixing tiny imperfections. They're more interested in eradicating serious problems that would generate a flood of customer complaints, said Eric Conley, CEO of Mixed Signals, which sells video-monitoring equipment.
To return to the wine-tasting metaphor, distributors want to be sure the product isn't corked.
“If I'm a cable operator, what I'm worried about at the end of the day is, I don't want people flooding to Verizon, and I don't want a huge number of truck rolls,” Conley said.
At EchoStar's uplink facility in Cheyenne, Wyo., director of operations Bob Crawford heads a group of 13 video-quality assurance staffers who check several hundred national channels. His team goes through a 200-point checklist prior to any service that is launched via EchoStar, which handles the aggregation of programming for satellite-TV provider Dish Network, to make sure everything is up to snuff.
But once the channels are live, Crawford and his team are looking mainly for show-stoppers, like the time in the past month one major programmer's feeds all went black for 18 minutes at around 3 a.m. on a Tuesday. (He declined to identify the programmer.) The group also has been assisting numerous local TV stations in properly configuring their digital equipment in the wake of last June's broadcast DTV transition, Crawford said.
“Most of the time we're putting out fires,” he said.
As cable and telco operators increase their network capacity, it's conceivable that the bandwidth limitations that require video compression in the first place could be eased. But that won't obviate the industry's need for golden eyes. There will continue to be bigger screens, more content, more devices, new applications — and new problems, said Paul Haskell, Harmonic's senior director of research and development.
“Our grandchildren may not have video-quality concerns,” he said, “but until then we'll have to spend a lot of attention on this.”
Learn the lingo of a golden eye — here are the six categories of video impairments Comcast Media Center's “golden eyes” look for:
|SOURCE: Comcast Media Center|
|Macroblocking: Edges of blocks or rows of blocks appear in a grid-like pattern; often occurs during dissolves between scenes or during high-action scenes.|
|Contouring: Color bands occur across shades of the same color, instead of a gradual change.|
|Haloing: Part of an on-screen graphic appears to extend into the background; typically seen around areas of high contrast.|
|Noise: Random speckles on an otherwise smooth surface; sometimes desirable as it can add a grainy, film-like appearance.|
|Smearing: Part of the image remains fixed in space while the adjacent parts of the image move, leaving a trail.|
|Pumping: The video or parts of the video appear to pulse at a regular interval.|