That took the race to implement video compression standard H.264. Manufacturers adopt this format as a standard for their digital video recorders, network cameras and encoders, promising video compression up to 50 percent compared to the MPEG-4. The application is serious, because it can greatly affect the total cost of ownership performance surveillance systems. Lower bitrate increases volume capacity digital data storage, at the same time reducing the load on network infrastructure or improving the quality of video at the same speed transmission of digital information.
The new standard defines a set of mathematical principles, whose application for video compression allows for a more successful outcome than that observed in the previously adopted standards. Many of the algorithms described in it is very demanding on computing power equipment or not applicable in some specific applications. To provide the necessary flexibility in the application, the standard defines seven different profiles. By profile we mean a set characteristics, provides for a specific group of practical applications of the standard. Many of the products for video surveillance are likely to be based on the application profile of the baseline. Baseline is designed for hardware devices with limited computing power.It requires the minimum possible delay of the signal in time. Other profiles are designed for a wide range of applications - from television and high-definition DVD (Blu-ray) to mobile phones.
Two different encoder formats used - H.264 and MPEG-4 - produced by Axis Communications, applying them to two typical video parts. The first part was shot at turning the camera, located in the parking lot, and the second - by a fixed camera, mounted above the door in the lobby business center. Both parts were shot in 4CIF resolution at 30 frames per second. Measurementof bitrates coming from each source of digital video based onboring procedure, method of test and error.Compression ratio was adjusted to achieve the visual equivalent level of video quality, which is formed by both sources.
In both devices footages which used compression standard H.264, fixed reduction of the average flux density of the data by about 50 percent.
Also, measured signal delay time for both devices was approximately 100 milliseconds. In the delay is the time required to digitize the video signal, compress the data stream and transmit it over the network, decoding and displaying a personal computer. A delay of 100 milliseconds - the value is very small, and therefore unable to influence the effectiveness of control PTZ cameras.
With increasing degree of signal compression video streams processed by MPEG-4 encoder and H.264 (and a corresponding reduction in bitrate and visual quality of the image), I noted that the "blocks" on a signal of MPEG-4 is becoming more visible, while the picture compressed in H.264, continues to be a "smooth", getting rid of the artifacts at the expense of image detail.
Despite the fact that the decrease in bit rate when using the H.264 codec is due to the increasing demands for computing resources, the format of H.264 - a major step in the development of surveillance systems and CCTV. The effectiveness of the implementation of the H.264 standard can be expressed in increasing the depth of archiving, reducing the cost of storing video data or to improve image quality. I think that the H.264 format are widespread as a standard for compressing video data in the security industry, significantly reducing operating costs for surveillance with higher resolution and frame rate.
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