Here Comes H.264
- By Steven Titch
- Dec 01, 2008
After a year of anticipation, IP cameras incorporating the H.264 compression standard are finally available. Their bandwidth and storage benefits will be music to the IT department’s ears. But what else do you need to know?
For starters, all H.264 cameras are not the same. Second, the cameras on the market now represent just the first-generation models that are limited by available processing power. Early implementers may not see a lot of difference between H.264 images and MPEG-4, but they will be getting a jump on future-proofing their surveillance systems.
The marketing mantra about H.264 has been that the standard achieves half the storage and bandwidth for the same frame rate as MPEG-4; or conversely, twice the frame rate for the same bandwidth and storage. H.264 itself comes under the MPEG-4 standards umbrella and also is known as MPEG-4 Part 10.
Smarter Compression
In layman’s terms, video compression algorithms replace entire streams of video data with simple instructions to the effect of “the next 10,000 bits are exactly the same as the one bit just sent” or “fill in the next 100x100 portion of the frame with the same 100x100 portion sent in the last image.” Naturally, then, a critical feature of any compression algorithm is how well it condenses images with lots of motion.
A major innovation of H.264 is its use of variable block-size motion compensation. That simply means there is more precise segmentation of an image where there is movement in a portion of a frame. H.264 can segment an image block as low as 4x4 pixels. Further, H.264 uses predictive motion compensation, where it can instruct a video controller to display moving images based on frames sent both before and after. The result is that H.264 cameras allow much more of the stagnant part of the frame to remain compressed while retaining the necessary detail and resolution on the elements of the image in motion.
Managing Expectations
The 2008 ASIS International Seminar and Exhibits, held in Atlanta in September, was something of a coming-out party for H.264.Vendors such as Arecont Vision, Axis Communications, IndigoVision, March Networks, Pelco, Sanyo and Sony were touting H.264 cameras of various types. Although vendors were high on the standard, many advised users to temper expectations, especially with the first generation.
“Most demonstrations compare H.264 cameras next to M-JPEG, not MPEG-4,” said Ed Thompson, chief technology officer for DVTel, Ridgefield Park,N.J., which supplies cameras and video management software and aims to support H.264 in the second quarter of next year. “You’ll be lucky to see any difference between [MPEG-4] Part 2 and Part 10.”
The reason is that processing power has not caught up with the standard’s capabilities,Thompson adds.Texas Instruments’ newest DaVinci digital signal processor for video will have a bandwidth accelerator, Thompson said, but will not be shipping until the beginning of 2009.That means current H.264 cameras still can’t take advantage of the complete toolset H.264 offers.
These tools include speedier motion searches. Alex Swanson, program manager at IndigoVision, Edinburgh,U.K., said H.264 is engineered to handle special types of motion particular to security, such as the image movement created by pan, tilt and zoom operation. IndigoVision’s cameras use H.264 to optimize PTZ search more effectively, Swanson said. But these tools add to the cost of processing.
“There’s a layer of detail below H.264 that’s not really discussed,” he said. “The algorithm is clear. How you do it is up to the vendor.”
Other tools and features H.264 supports is a set of up to 15 analytics algorithms, including trip wire, unattended bags and crowd counting, said Peter Wilenius, vice president of investor relations and corporate development at March Networks, Ottawa, Ontario. H.264 will compete with other standards,Wilenius said, although it is particularly suitable to megapixel cameras because of the sizable amounts of video data they need to process and transmit.
“H.264 is a necessary evil in megapixel cameras,” said Tom Carnevale, president of Sentry360 Security Inc., Naperville, Ill., a megapixel camera supplier not yet supporting the standard. Currently, however, when images are placed side-by-side, Carnevale maintains there is no significant difference between H.264, MPEG-4 or M-JPEG. H.264, he said, is a future-proofing mechanism. On the other hand, M-JPEG, which Sentry360 cameras do support, “will remain a very good open architecture.”
On the server side, H.264 is “delivering like it’s supposed to,” said Roger Shuman, marketing manager for Exacq Technologies, Indianapolis, which supports Arecont Vision’s H.264 camera suite. But like others who are high on the technology, he said there needs to be more processing power on the client side before users see a full payoff.
Finding its Place
In addition, users should avoid viewing H.264 as if it were a magic bullet for all bandwidth, functionality and cost issues. “H.264 is not completely understood by the market.There is not a wide selection of cameras, recording or management systems. It’s still in its infancy,” said Paul Bodell, vice president of sales and marketing at IQin- Vision. “There’s great bandwidth savings but it’s a processor hog.”
Most users, Carnevale said, will likely adopt a mix of cameras after considering quality and cost trade-offs.The improved motion compensation aspects make H.264 cameras especially suitable for dense, high-traffic areas where there is a lot of activity occurring against irregular backgrounds. An H.264 camera, on the other hand, would not add much value if placed on a stationary mount to monitor a seldom-used back door.
Still, greater image quality will require a trade-off in terms of bandwidth, Bodell said. In most situations, H.264 will deliver greater bandwidth economy, but the busier the area under surveillance, the more this economy will drop.
While the outlook for H.264 is extremely favorable, gauging its full utility may take some time. For one, video management software manufacturers are traveling up the learning curve alongside camera makers. Even major players such as Milestone Systems AB suggest the jury is still out.
“H.264 is another form of MPEG.We don’t know what it’s going to do,” said Kent Sumida, presales support manager at the Brøndby, Denmark-based company. “We haven’t seen enough of it to come to a conclusion about file sizes and bandwidth consumption. The true test is movement—how it handles slow pan, fast pan and zoom. Then, we’ll see how it goes.”
This article originally appeared in the December 2008 issue of Network-Centric Security.
About the Author
Steven Titch is editor of Network-Centric Security magazine.