SubscribeFor network video security applications, it is a foregone conclusion that bitrate optimization is critical to a successful implementation.
In addition, the use of open, inter-operable standards for video and audio compression enables the long-term viability of security assets without locking customers into proprietary solutions and provides lower total cost of ownership.
H.264 Encoder
The ATEME H.264 encoder has been optimized and enhanced to provide outstanding video quality at exceptionally low bitrates using this open-standard approach. Even compared to the previous-generation open MPEG-4 encoding technology, customers can expect to benefit from a 40% reduction in bitrate for the same quality video. This results in reduced overhead on the network, reduced storage requirements due to smaller file sizes and most importantly reduced cost to the end user.
Video Encoding Technology
ATEME has been refining its H.264 encoding technology over many years and in that time has deployed numerous solutions to their customer sites worldwide. Examples of such deployments include Highways, Subway stations and Toll stations. H.264 (Mpeg4 Part 10 or AVC (Advanced Video Coding)) is the successor to the hugely-successful MPEG-4 (MPEG-4 part 2) video encoding standard and is the latest cutting-edge video compression standard available on the market today. It differs from other encoding technologies (MPEG-2, MPEG-4) due to its many sophisticated techniques that enable video to be compressed much more efficiently, making it more flexible and suitable for any type of network constraints that might exist.
Technology Details
Like other encoding technologies the notion of profiles is used in order to bundle together certain sets of features that target specific types of applications. There are four primary profiles that exist in H.264:
- Baseline Profile (for low-delay applications such as videoconferencing and mobile applications)
- Extended Profile (for mobile streaming applications)
- Main Profile (for interlaced video applications and broadcast media applications)
- High Profile (for high-definition television applications)
The enhanced compression in H.264 is achieved primarily due to the following advanced techniques:
- Motion estimation, which minimizes temporal redundancies (similar blocks at different locations in two video frames);
- Intra estimation, which minimizes spatial redundancies (duplications of elements within a portion of a frame); Reduction of compression artifacts;
- Entropy coding, which assigns a smaller number of bits to frequently encountered symbols and a larger number of bits to infrequently encountered symbols
The two flavours of entropy coding used in the ATEME codec are CABAC (Context-adaptive binary arithmetic coding) and CAVLC (Context-adaptive variable-length coding). Data is compressed much more efficiently with CABAC than CAVLC; however much more processing power is required to accomplish CABAC encoding. Although CAVLC is less complex than CABAC, it is still much more efficient than other techniques used in coefficient encoding such as that used in MPEG-4 encoding.
Deblocking Filter
The further advances in video quality and prediction performance are achieved through the use of a deblocking filter which removes block artifacts (common to other encoding techniques). This is achieved by smoothing out the edges between the blocks within a frame. This filter also greatly improves the visual quality of a frame when compared at similar bitrates to MPEG-4 encoding.
Incorporated into the ATEME H.264 encoder are many unique, feature-rich tools which complement and maximize the benefits gained by customers from this latest encoding technology. They have a revolutionary new feature that enables two H.264 video streams to be encoded (from the same source) and streamed (at different frame rates), all on a single DSP. This feature is revolutionary due to the limited processing capability actually available on the DSP and is achievable due to the streamlined performance of the ATEME encoding engine. This feature is important for situations where video is being monitored at full frame rate and recorded at a lower bitrate.
Variable Frame Rate
Variable Frame Rate (VFR) is a feature that reduces and increases the frame rate depending on the movement in a given area i.e. when there is no activity in the defined zone; images are not actually needed and therefore can be discarded. This feature - together with the already low bitrates - further reduces the amount of disk space required to store a video file.
Automatically adjust the bitrate depending on the actual image activity. This latest feature is perhaps the most significant technology incorporated into ATEME’s H.264 encoders in recent months. This gives the H.264 encoder the ability to constantly produce razor sharp images at fluctuating bitrates. The need for this arose due to a limitation with Constant Bitrate (CBR) mode encoding. By implementing this process, bitrate reductions of 60% can be achieved compared to bitrates with similar MPEG-4 video quality.
CBR Mode Encoding
ATEME Engineers found that CBR mode encoding produced great picture quality when there was low activity - but when activity increased and there was a lot of motion, the picture quality could be degraded. With this latest technique the likelihood of degraded or dropped frames is removed, as it is much more flexible than CBR and also allows the image to remain sharp and clear while still providing user control on the maximum bandwidth used (due to the max bitrate parameter). Another important advantage compared with CBR is its high efficiency (bitrate is consumed only when necessary), resulting in even less network traffic and reduced storage requirements for the end user.
Open Standards Value Proposition
ATEME’s H.264 encoding technology complies 100% with the guidelines governing the encoding standard, a fact that is not always the case with other manufacturers. Being fully standard compliant is an important consideration when deciding to purchase any encoding technology.
A lack of open standards results in reduced choice and can lock customers into proprietary systems. Purchasing standard compliant technology gives organizations more flexibility and also means they are not forced to purchase expensive complete solutions. Customers will have the option to combine Security System components without the worry of integration and data format issues. If the customer has options then more competition exists, meaning the customer will benefit from lower product prices. The fact that ATEME is standard compliant means that H.264 video streams can be decoded with compliant decoding software such as VLC player or QuickTimeŽ, which is an important licensing consideration when managing video over a large network.
IP Network Video Solutions
ATEME’s current product range based on the latest H.264 technology significantly reduces the costs of updating Security Systems by integrating with existing infrastructure. Through ATEME, it is possible to retain existing analog cameras and simply install ATEME’s H.264 encoder products. This will transform standard analog CCTV security solutions into a state-of-the-art IP Network Video Security Solution combining the best in video quality at the lowest possible bitrates.
Alternatively however, for completely new Video Security installations, customers still choose to use analog cameras with ATEME H.264 encoders. The reason for this is that the video quality obtained from an analog camera plus an ATEME encoder is far superior to the video obtained from IP cameras. This is due to the fact that the IP camera technology is still in a stage of evolution and is still constrained by hardware/price limitations. This trend surely will change over the next 5 years.
Summary
ATEME are constantly pushing the boundaries of what is possible to achieve with the H.264 technology thus ensuring that its customers get the maximum benefit from their financial investment. If you are serious about Video Security then the ATEME H.264 solution is one of the best options available.
