مطالعه بر روی فن آوری هسته ای از استانداردهای برنامه نویسی ویدئو جدید H.264/AVC

We introduce briefly the basic principle of the standardized coding/decoding H.264/AVC. We have analyzed and studied in detail the core technology of H.264/AVC standard, including motion estimation and motion compensation, forecasts in a frame and between the frames, integer transform and quantization analysis, entropy coding methods, deblock filter, new photographic image type, aspect-oriented IP and wireless environment, etc. The H.264/AVC standard has solved the contradiction between the image quality and the coding efficiency, its effect is obvious, but many advantages acquired exchange for the sacrifice of computing complexity, therefore, to achieve greater coding efficiency will be the next studying emphasis at the same time of reducing the computing complexity.

International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) and International Organization for Standardization (ISO)/ International Electrotechnical Commission (IEC) are two different organizations of the current international standards for the video encode. The video encoder standard formulated by ITU-T is called as the video encoder proposal, named as H.26X series, for example, H.261, H.263. The video encoder standard formulated by ISO/IEC is called as MPEG-X, for example, MPEG-1, MPEG-2, MPEG-4. The H.26X series is mostly used for real-time video communication, for example, video conferencing, videophone; The MPEG series is mostly used for video storage (DVD), video broadcast and video streaming media. Except for the joint development of H.262/MPEG-2, in most cases, the two organizations formulate independently the relevant standards. In 1997, ITU-T VCEG cooperated with ISO/IEC MPEG again, they set up the Joint Video Team

Due to the results of using a lot of new technologies, the H.264/AVC standards in all aspects such as system structure and efficiency are superior to the preceding video encoding standards. In the same image quality, the H.264/AVC algorithm saves 50% or so code rate in terms of preceding standards such as H.263 or MPEG-4. At the same time, it has a strong error resilience property to adapt itself to the video transmission of wireless channel with a high packet loss rate and serious disturbance. So H.264/AVC supports the hierarchical encoding transmission in different network resources, achieves a steady image quality and can be adapted to the video transmission between different networks. In the video application domain, the image quality and encoding efficiency always are a dilemma. The encoding efficiency of H.264/AVC standards is improved because its entropy coding technology adopted the encoding of CAVLC and CABAC, successes to solve the problem. But the price of the superior performance of H.264/AVC is that the computing complexity increased greatly. It is estimated that the computing complexity of encoding is about three times as large as H.263, the computing complexity of encoding is about two times as large as H.263. At the same time of reducing the complexity, to achieve greater efficiency of encoding will be the next priority of study.