MPEG-4 Compression Expands Beyond Distribution
By Carl Lindemann
MPEG-4 h.264 compression has already transformed the consumer landscape, allowing companies like DirecTV to distribute hundreds of HD channels and more as it promises a two-to-one bandwidth saving vs. MPEG-2. Visitors at the 2009 NAB Show will see products for emerging applications, especially HD newsgathering, and MPEG-4 benefits for high-bandwidth content like sports will be in sight at the show, although gear to implement will have to wait for future NAB conferences.
“We’re at the beginning on the MPEG-4 implementation,” says Lisa Hobbs, Tandberg Television VP of business development, Satellite & Broadcast. “We’re looking forward to continuous improvements in both the technology and the marketplace for these products.”
It has been a few years since MPEG-4 took off in the satellite business. For those servicing that industry with products today, things are looking up, despite the downturn economy.
“Our business is rocketing,” says Bob Wilson, general manager of Motorola’s networked video solutions group. “It’s gratifying, but kind of scary wondering if it will hold up under the circumstances. The whole MPEG-4 space is very hot right now.
Wilson adds that all service providers can’t get enough HD up fast enough. “What’s driving a big part of business is both the uplink business in MPEG-4 and a series of products that allow transcoding back to MPEG-2 in the cable headend. That’s so you don’t have to trade out the rest of the infrastructure including set-top boxes.”
What’s planned for NAB 2009? Getting ready for MPEG-4 to the consumer. “The first dual-format set-tops for MPEG-4 and MPEG-2 in the same box, though it will be a while before that becomes meaningful,” says Wilson.
Making a Contribution to Contribution
Transmission is just MPEG-4’s first success. According to David Mitchinson, business development director, DSNG Systems, for Tandberg Television, contribution and helping TV stations and networks get content from the field back to a broadcast-operations center is the next frontier and will open the door to more-economical HD newsgathering.
“Currently, our products are very much focused on using MPEG-4 for newsgathering and general-purpose contribution,” says Mitchinson. “It is a big market for us.”
Mitchinson’s technical paper for NAB 2009, “The Role of MPEG-4 Within Contribution,” explains the key to unlocking MPEG-4’s potential in this new area. Contribution, he says, is a very different use for MPEG-4 than transmission. With transmission, coding/decoding delays are unimportant. There’s time to bring the entire MPEG-4 toolset into play with enormous gains in efficiency. But where time is a factor, things aren’t quite so simple.
“For a lot of contribution applications, latency is critical,” he says. “Because of the way MPEG-4 works, you have to start making compromises and choose the tools you can use quite carefully. Where you need to achieve 500 ms or less for encode/decode, the biggest advantages [over MPEG-2] are with low-bitrate applications like newsgathering and general-purpose contribution.”
The Highs and Lows of MPEG-4
Why is MPEG-4 ready to deliver for low-bitrate applications like newsgathering while high-bitrate applications like sports lay further down the road? The answer comes down to mathematics. Percentage-wise, MPEG-4’s gains over MPEG-2 are much higher at the low end of the bitrate spectrum. According to Mitchinson, this means bandwidth-efficiency gains of up to 50%.
He says that looking at the difference between typical news and sports content also explains why MPEG-4 yields different savings. News images have a great deal of repetition. With sports footage, the entire frame shifts constantly.
“There is interest in using MPEG-4 to deliver high-bitrate sports content,” says Mitchinson. “At high bitrates and with very demanding content, MPEG-4 will still deliver efficiency savings. However, these will not be as significant as for newsgathering.”
As bandwidth savings over MPEG-2 drop to 25% or less, Mitchinson expects that the adoption of “fidelity extensions” improving HD image quality will be needed to drive future adoption of MPEG-4 for high-bandwidth applications.
Will Economics Trump Technology?
MPEG-4 looks to solve bandwidth issues in going from SD to HD newsgathering. But that is moot until HD newsgathering becomes an everyday reality.
“People are doing HD news in the studio, but there is still the strong belief that a 16:9 high-quality SD that you upconvert from the truck is more than adequate for a lot of the field reporting,” says Tom Lattie, Harmonic director of Broadcast & Satellite Solutions.
Letting go of this holdover from the SD era is even harder given the current economic climate.
“[Broadcasters are] looking to save money but don’t want to spend money now,” says Lattie. “We can talk about MPEG-4 vs. MPEG-2 compression, but they’re not necessarily going to go out and buy new [HD] cameras for these trucks and field reporters. They’re staying with SD now and want easy upgrade to HD at some later date when they have more capital to throw after that.”
Despite these challenges, Lattie says the 2009 NAB Show will feature a growing array of MPEG-4 products that open the door for those looking to produce end-to-end HD news.
Not If but When
At the station groups and network level, the place of MPEG-4 for HD newsgathering is clear even if the timing is not.
“As we all make transition to digital microwave vis-à-vis the Sprint/Nextel convergence, the next step is to look at MPEG-4 for return of both satellite newsgathering and ENG,” says Del Parks, Sinclair VP of engineering and operations. MPEG-4 does not translate into bottom-line savings today. “The efficiency is in the bandwidth, not in the dollars,” he adds.
This is problematic because the need for “dollar-efficiency” is paramount.
“We’ve in a very conservative stance regarding investments of any nature,” says Ardell Hill, SVP, broadcast operations, Media General Broadcast. “We’re investing in a few things to maximize efficiency and reduce costs by automating the newscast process, centralizing processes like graphics, traffic, and master control.”
What about MPEG-4’s potential as HD newsgathering takes hold?
“Today, we have very few deployments in the field in HD,” said Hill. “In two or three years, as we cycle through the equipment we have on the street now, that will change. The cost of equipment is coming down, and so there will be little price difference between SD and HD [ENG equipment].”
Hill observes that, to their credit, manufacturers and those on the supply side of technology have not stopped their investments and efforts at looking for those opportunities. “My hat’s off to those companies and those supporting them,” he says. “For now, we’ve all got to weather the storm.”