Not all fizzy wine is Champagne. The “high-definition” TV shows that ABC.com plans to debut in early July will be extremely compressed versions that, while saving on bandwidth, will not be comparable to the HDTV services cable or satellite providers offer today.
The high-definition video on the broadcaster’s Web site would technically meet a minimum definition of HDTV: It will be delivered at a screen size of 1280 by 720 pixels at 24 frames per second.
But the video will be encoded at bit rates far below the MPEG-based HD streams from cable operators, and compression has a bearing on the visual quality of the picture. Disney-ABC Television Group vice president of technology Skarpi Hedinsson said his group has tested HD-resolution video compressed at rates between 850 Kilobits per second to 2 Megabits per second.
“We’re not talking 5 Megabits per second or something crazy like that,” Hedinsson said.
Cable providers typically encode HD streams at between roughly 12 and 19 Mbps, using the MPEG-2 format, but even the more-efficient MPEG-4 standard requires at least 5 Mbps for high-definition video displayed on large-screen TV sets.
ABC.com uses a video codec from On2 Technologies, a small New York video-software developer. Hedinsson said the latest versions of its codecs provide better quality at lower bit rates. “We have invested in a facility that has very sophisticated encoding,” he said. “Three or four months ago I would have said we wouldn’t have been able to do this.”
The site already provides standard-definition video encoded at 1.5 Mbps, Hedinsson said, so the step up to 2 Mbps seemed feasible: “For us, the delta between HD and SD is not really that great.”
Because ABC.com’s videos are delivered as files and not as live, streaming bits, the service is not susceptible to bandwidth fluctuations. Hedinsson noted that the site will include an automatic bandwidth indicator that shows when someone’s broadband connection is sufficient to deliver HD content.
Still, Hedinsson acknowledged that ABC’s online HD — for now — won’t measure up to what viewers are used to getting on their TVs. “Does it look as good as over-the-air or cable [HD]? Well, no, there’s more compression,” he said.
The more highly compressed a video signal is, especially with high-motion content like sports, the more likely it is to exhibit visual aberrations such as pixelation or “macroblocking,” in which portions of the screen are spattered with multicolored tiles.
Another caveat: A user’s PC must have sufficient processing capability to be able to decompress the “HD” video.
“It’s not going to be bandwidth that is the problem. It’s going to be the horsepower on the PC end,” Hedinsson said. “You do need quite a bit of CPU [central-processing unit] power to render 24 frames per second. We are going to do our best to educate users on what their experience will be like.”
ABC.com’s HD channel, such as it is, will first feature a limited amount of content from its most popular primetime series, including Lost, Desperate Housewives, Grey’s Anatomy and Ugly Betty. When ABC launches its new season in September, the site’s HD lineup will be expanded.
FEUDING OVER QUALITY
The debate over HD picture quality doesn’t belong only to videophile nerds. It’s central to a raging battle between DirecTV and the country’s two biggest multiple-system operators (“Competition in Definition,” May 28, 2007, page 12).
Earlier this year, at Time Warner Cable’s request, DirecTV was ordered by a federal judge to stop claiming in advertising that its HDTV quality was better than that of cable operators. (The judge did allow the direct-broadcast satellite operator to continue claiming it will soon have three times the HD capacity of cable; the case is pending.)
Then DirecTV last month fired off a lawsuit against Comcast, asserting that the MSO’s ads, citing a survey in which Comcast’s HD picture was preferred to satellite’s, were false.
While ABC’s online-HD claims may not provoke similar litigious responses, some observers detect mainly marketing hype.
“It might sound sexy per se to say, 'We’ve got HD programs online,’ ” said Bruce Leichtman, president of the Leichtman Research Group. “But certainly, the best way to watch HD is on a big-screen TV.”
To Hedinsson, though, the business goal of ABC.com’s HD launch is to keep ratcheting up the quality of video available over the Internet as broadband speeds rise. “We derive revenue from every single online viewer,” he said. “The question is, How do you keep the viewer engaged?”