Is H.264 Today’s Next Show Biz Star?
It’s not often that a standard will receive recognition along the lines of an Emmy award. But it did.
The members of the Academy of Television Arts & Sciences recently honored the performance of the Joint Video Team Standards Committee for the development of the High Profile for H.264/MPEG-4 AVC. It enables high-definition images in H.264 video encoding to deliver HD video over satellite and cable TV as well as Blu-ray Disc.
Complexities Will IncreaseSince H.264 uses a more complex algorithm, it requires more CPU resources to compress and decompress the video signal. The consequences of this, according to Mark Wilson of Infinova, are that the camera requires more power and generates more heat, which, in a harsh environment, may result in reliability issues. Second, since H.264 uses intraframe compression in high-motion scenes, there can be compression artifacts or blur introduced into the video. This affects the forensic value of the video and could cause issues with evidence in court. Yet you shouldn’t see any complexity, according to Tom Galvin of Samsung GVI Security. Instead, there should be a seamless transition and adoption is happening quickly.
It’s Been Around a WhileWhether viewing the good or challenging, this codec show biz star is no fresh face. Also known as MPEG-4 Part 10, H.264 is a digital video codec standard finalized in 2003 that promises to compress video data to a very low bit rate while maintaining high-quality video. Right now, many video surveillance systems are forced to sacrifice bandwidth and costly network storage. However, if the promise of H.264 is realized, the same resources being used today will be capable of transmitting and storing more video streams with higher frame rates and resolution.
Anixter’s Infrastructure Solutions Lab recently conducted several tests to compare the differences in bandwidth consumption between H.264 and MJPEG video streams using a single camera from a manufacturer that supports both compression technologies.
Sorting out the HypeBeyond lab tests, there are a lot of claims flying over H.264. Some say that the codec is the most aggressively marketed and least understood of the new technologies in security. But right or wrong, there is a place for it.
From Chips to FirmwareOf course, H.264 capability is available with some manufacturers through a simple firmware upgrade to their IP cameras and encoders. You should ask about frame rate and resolution limitations if you are running H.264 encoding and possible other functions like video analytics on hardware designed for MPEG-4, suggests Bob Banerjee of Bosch Security Systems. On new hardware, ask about the ability to view a low latency stream, and record a higher compressed (but high latency) stream. By the way, in a network, latency, a synonym for delay, is an expression of how much time it takes for a packet of data to get from one designated point to another.
Estimating Motion is Important
Factors that will cause bandwidth and storage demands to vary widely include wind blowing the trees. As the tree moves in the video, it will increase the bandwidth and storage required. “Imagine having to estimate how frequently the wind will blow before you can properly estimate the amount of storage required for your video surveillance system,” suggests DeAngelis. Rain and snow are viewed by a temporal encoder as nearly 100 percent scene motion. This greatly increases bandwidth and storage requirements. Wind moving the camera’s mount is the worst kind of scene motion because 100 percent of the scene is changing 100 percent of the time. A camera mounted on a pole that could be subject to such disturbances would not be a good choice for H.264 encoding. Speed of the objects being viewed also will impact bandwidth and storage as well as image quality.
How can end users maneuver through the number of cameras, throughput and frames per second of H.264 vs. other codecs?
This is very, very difficult with H.264 compression. With H.264, anytime something moves in the field of view, the bandwidth and storage requirements will go up, by how much depends on how much motion there is and what the desired image quality is. Normal, everyday occurrences, which are almost always in the field of view of a security camera, can cause significant bandwidth and storage problems, says the IQinVision executive.
He adds, some examples of factors that will cause bandwidth and storage demands to vary widely include, (1) Wind blowing the trees. As the tree moves in the video, it will increase the bandwidth and storage required—imagine having to estimate how frequently the wind will blow before you can properly estimate the amount of storage required for your video surveillance system. (2) Rain and Snow are viewed by a temporal encoder as nearly 100 percent scene motion, this greatly increases bandwidth and storage requirements. (3) Wind moving the camera’s mount is the worst kind of scene motion, because 100 percent of the scene is changing 100% of the time. A camera mounted on a pole that could be subject to such disturbance would not be a good choice for H.264 encoding. (4) Speed of the objects being viewed will impact bandwidth and storage as well as image quality.
Choose Your Level of EnhancementIt is important to remember that not every enhancement is implemented in all instances of H.264, suggests Adair. With several profiles in the standard, most security cameras use the Base Profile, which has been designed for low cost applications such as video conferencing, and does not implement many of the H.264 features when compared with the High Profile, which has become the standard for Blu-ray encoding. In general, the more features included, the more processing power required to effectively implement it. And the higher the price tag.
The Evolution of Video CompressionThe three most commonly used video recording/compression formats are: M-JPEG, MPEG and H.264. All perform the basic function of compressing the video information by eliminating redundant or irrelevant information. Redundancy reduction looks for patterns and repetitions and irrelevance reduction looks to remove or alter information that makes little or no difference to the perception of the image, according to Jason Oakley, CEO at integrator North American Video.
Two Lanes, Same Street EndIn addition to the standards work through the Security Industry Association, the trade group of manufacturers and service providers, there are two organizations bringing their idea of a flattened playing field to IP networking related to security systems.
Hold On: Check Out Intra and Inter, Lossy and LosslessWith any complex technology, there are terms that chief security officers and security directors should know while, at the same time, avoiding the nuts and bolts to be handled by a systems integrator.
Resolution – What is your requirement for image quality?
Frame Rate – What do you need to see in the image? What level of detail is required? It is essential to provide the optimal frame rate and achieve the desired storage and archive requirements.
Weather – Is there a lot of snow, rain or wind where the camera is located – all of which can lead to scene motion (motion between frames)?
Lighting – Is the lighting constant or changing? What needs to be seen in low-light conditions? Low-light conditions can lead to noisy images.
Scene Motion – How much motion occurs from frame-to-frame?
Object Speed – What is the speed with which objects move through the field of view?
Camera Motion – Is the camera moving or fixed? How quickly or slowly does a camera pan, tilt or zoom?
Recording – How long are images stored? Is recording constant or based on motion?
Live Viewing – What level of latency is acceptable? Is real-time viewing or multi-camera viewing required?
Bandwidth – How much bandwidth is required to meet your specific requirements? Do any bandwidth limitations exist?
Remote Access – Is remote access to video required?
PC/Servers – What memory and processing power is required to meet your requirements? What PCs are available for viewing video?