Television programmers that want to create high-definition video to feed growing consumer demand don't have an easy task right now. Not only must they pony up funding for new HD cameras and production equipment — they must also come to a resolution on which display format to use.
As of right now, there is no Federal Communications Commission-mandated HD standard, nor is there consensus in the television industry as to which format to use. Still, there are two distinct camps: One advocates the 720p format, the other favors 1080i.
As many HDTV sets can render either format, the choice appears to be in the eye of the programming beholder.
The two HD formats are distinguished by the number of vertical lines they present, and by how each line is scanned and changed as the picture moves. The 720p format offers 720 lines of resolution — a significant boost compared to the 525 lines of standard-definition digital TV.
The "p" stands for progressive, a scanning method in which all lines in a video frame are scanned and updated 60 times per second.
The 1080i format offers 1080 lines of resolution, but takes a different scanning tack. The "i" stands for interlaced, a strategy in which the scanning work is divided into halves, with alternating lines scanned 60 times a second. Each line is therefore scanned 30 times a second.
Proponents of 720p say that because the image is fully refreshed 60 times a second, it is better for rendering high-action video. And since video-compression rates are equal, 720p pictures will take up less bandwidth than 1080i images.
On the flip side, 1080i mavens argue that the greater line count will produce a better picture, and the fact only half of the information is updated at a time also lessens the processing power needs of HDTV sets or digital boxes.
A phalanx of networks — including broadcasters NBC and CBS and premium channels Showtime and Home Box Office — have opted for 1080i.
Showtime, which launched HD feeds for the East and West coasts in January 2000, is sold on the 1080i format because of the greater resolution it provided, according to Showtime Networks Inc. senior vice president, corporate strategy and international Glenn Oakley.
"We chose the highest transmission standard available," he said. "We believe it gives the opportunity for the best picture, especially given the kind of content that we put out, which is theatrical and entertainment content — high action."
There is also a greater supply of 1080i HD cameras and production equipment, making that standard less costly and easier to deploy, Oakley added.
"It really is the friendliest for satellite and cable, as well as transmission and our own playback," he said. "And it works the best throughout the entire transmission sequence, which includes tape retrieval, playback, uplink, our own bandwidth, 64 [quadrature amplitude modulation], 256 QAM.
"We wanted those things that worked optimally well with the highest pixel rate and bandwidth that people can distribute."
As for bandwidth, Showtime could use greater compression to lessen the payload of its HD stream. But the pay TV programmer has increased the bandwidth of its stream in the last year — from about 13.5 megabits per second to 15.1 mbps.
"The reason we are doing it is to take a fabulous source content, which is movies, series and originals, and bring it into the home with as much, if not better, quality than you are going to be able to see there," Oakley said. "And to cut back on bandwidth — of course, being sensitive to the needs of our distributors — goes counter to that.
"So anything we can do to increase the quality of the signal, the picture or the content we will endeavor to do."
Sports network ESPN is among the advocates of 720p. Its reason for doing so is not a matter of resolution, said ESPN HD managing partner Bryan Burns.
"There are a lot of folks who say 'Well, 1080 is more than 720, and our belief is it's not about the numbers — it's about the 'p' and the 'i,' " he said. "It's about progressive versus interlaced."
Although Burns acknowledged that 720p equipment costs more, the format's ability to update the entire picture 60 times a second is better for displaying moving objects.
"If you have news anchors sitting on a set where there isn't as much movement, that's not a big deal," Burns said. "But when you have hockey pucks flying around and soccer balls and footballs and baseballs and swinging bats and so forth, movement is the critical component of sports television.
"Progressive, because of the way it paints the picture, is much more responsive to the motion of sports than is interlaced, and that is the reason we made the call to go progressive."
For that reason, Burns also thinks 720p will likely become the HD norm for sports programming. Already, ABC Sports — ESPN's sibling within The Walt Disney Co. — plans its high-definition content using 720p. That also will hold true for ABC's entertainment programming.
"When you put together the total amount of things that ABC Sports does and what we do, the vast amount of sports in high-def will be in 720p," Burns added. "Between the two companies — ours and theirs — we control the vast majority of sports programming."
For other programmers, the difference between the two formats is not as stark — nor are they as adamant when choosing a format.
Discovery Networks U.S. rolled out its Discovery HD Theater this summer using the 1080i format — but only because at the time, more 1080i production equipment was available, and more 1080i sets were in viewers' homes.
While 1080i still dominates the production-gear sector, Discovery Networks new-media division president John Ford expects that will change over time.
"If we were in the same position today, I'm not sure what our decision would be," Ford noted. "We haven't actually gone through that. It might be the same; it might be different. We just have to do a reassessment.
"I think the install base of receivers is still predominantly 1080i, but I think the production equation is changing, because Panasonic is making a pretty aggressive move with its Vericam to basically evangelize the production community to use the 720p camera," he added.
That reassessment would hinge on whether the bottom line of HD production has shifted.
"If there are some substantial savings to be realized, either in production or post-production, transmission or local cable distribution — pick a place in the chain that would make it more cost-effective — that would be a compelling reason to move from one format to another," Ford said.
If that happens, the network won't be tossing out the 1080i cameras and equipment now in use. Armed with high-definition master tapes, Discovery can convert material shot in one HD format to another for transmission with minimal effort, Ford said.
"We have not reason to do that right now, but we are certainly saying to producers, 'If you want to produce your show in 720p and you can find the production support to cost-effectively edit your show, that's fine with us,' " he said. "We can just dub it over to our 1080i master. It's not as simple as a standard tape dub, but it is not that expensive or complicated either."
For now, the network has no reason to switch from 1080i, but it is taking a wait-and-see attitute with respect to technology.
"We've still got our options open for the future, and those are still preserved for the future," Ford said.