Monday, February 14, 2011

On: video surveillance definition encoding of four standard

Hi-def video encoding most commonly used encoding format is MPEG2-TS, MPEG4, H.264 and VC-1 the four algorithms.

MPEG2 from MPEG (Moving Picture Experts Group) moving picture experts group-setting, this is the International Organization for Standardization (ISO) was established in 1988, the task of designing relevant movement coding standard working group that developed the standards of the international common criteria.

DVD MPEG2 encoding is, as technology improved, it is also in high-definition video has been applied. The biggest disadvantage of MPEG2 is the file size too large, but it also has an advantage that is relative to the other two kinds of coding, it is system resource consumption is the smallest. But as the hardware technology, H.264 and VC-1 decoding will inevitably become DVD, any mainstream configurations can provide smooth playing.

MPEG4 is mainly used for low bandwidth applications and interactive graphics applications (games, etc), interactive multimedia (WWW, content distribution and access), MPEG expert group set up a working group of the MPEG4 to promote these three areas of integration.

In early 1999, defined a standard framework for MPEG4 (first edition) as an international standard (ISO/IEC14496-1), provides a variety of algorithms and tools Second Edition was published by the end of 1999 as an international standard (ISO/IEC14496-2).

H.264 is perhaps the most promising one, relative to MPEG2, MPEG4, the compression efficiency is three kinds of coding.

H.264 standard by the International Telecommunication Union Telecommunication Standardization (ITU-T) and the International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) joint research publication, H.264 has two names, a followed the name of the H.26x ITU-T organization, called the "H.264" and the other is the AVC (advanced video coding). H.264 format maximum features in ensuring the quality of the picture, it can put the file size control in MPEG2 format of one half or even one-third. So the higher the compression ratio, the better the IP and wireless networks channel of adaptability, in digital video communications and storage areas are becoming more widely used. However, it's important to note the superior performance of H.264 for cost increase calculation complexity, H.264 hardware requirements.

Microsoft in September 2003, presented the VC-1 encoding format (development code name Corona), has now been Movie eam, Modeo and so many companies to adopt, at the same time is also included in HDDVD and Blu-ray, including Warner, film company and universal also uses this format.

Microsoft windows Media-based VC-1 Video9 (WMV9) format, and WMV9 format has now become standard practice VC-1. VC-1 is finally approved HD encoding format, because Microsoft's background, so this encoding format is not a small glimpse, relative to MPEG2, VC-1 higher compression ratios; however, relative to the H.264 encoding and decoding of calculation is slightly smaller.

AVS is based on China's independent innovation technology and international open standard technologies, construction, mainly for high-definition and high-quality digital TV broadcasting, network television, digital storage media and other related applications, high performance (and H.264 rather), low complexity (algorithm complexity than H.264 obvious low), our grasp of the main intellectual property, patent licensing mode for a simple and low cost.

Based on this, it is capable of supporting AVS standard national digital audio/video industry development of important criteria, but also security monitoring industry should adopt important standards.

JPEG2000 is the image encoding format, and not video encoding format, the beginning of the design is used to replace the JPEG, and video sequences of each frame is thus an image compared to its predecessors, JPEG, JPEG2000 gave to discrete cosine transform DCT-based chunk encoding, instead of using a wavelet-based analysis of multiple encoding compression rate than JPEG high of about 30 percent, while JPEG2000 support lossy and lossless compression.

JPEG2000 there are several important properties that support "progressive transmission" and "coding" region of interest. In the definition, it can be decoded with a screen size of a quarter, then half, finally decode out the whole picture; in the image quality is concerned, it can transmit images of the outline, and then gradually transfer data to improve image quality, so that the image is clear from the obscurity to; " Region of interest "means that a user can specify the image on the ROI of compression quality, you can also select the specified part of unzipping, makes it easy to highlight key points. But the JPEG2000 for compute is too large, the compression rate is not high, it is difficult to achieve in embedded real time systems, storage transport has also put forward higher requirements, currently only some HD dedicated system uses this algorithm.

In the coding chip, usually with DSP, ASIC, to choose from.

DSP programmes such as Leonardo da Vinci TMS320DM6467 digital media processor is a DSP-based SOC (System on chip) that integrates 300MHz of ARM core and a DSP cores and adopts high-definition video co-processor, H.264HP (1080p30fps, 1080i60fps, 720p60fps) synchronization multi-format high definition encoding, decoding and transcoding, outstanding performance. There is a high-definition entry-level TI chip DM355, its built-in codec algorithm implementations to 720p format and 30 frames per second speed for high definition decoding capabilities, MPEG4SP is quickly develop entry-level HD encoding a good choice of products. ASIC solutions such as the haisi 3511Processor, based on ARM9 processor core and video hardware acceleration engine, high-performance communication media processor, has a highly integrated, programmable, supporting H.264 and MJPEG (MotionJPEG is a video compression format, where each frame images use the JPEG encoding), and many other advantages of the agreement, can be widely applied to real-time video communications, digital video surveillance, webcam, etc.

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