The Development Of Software Of Digital Decode Broadcast Based On H.264 Standard

With the development of information technology in 21st century,there grows the need of storing and transmitting video information efficiently. The Property of digital video limits the expansion of multimedia services,so it is necessary to develop techniques for compressing these video data. H.264 standard is jointly being made by ITU-T Video Coding Experts Group and ISO/IEC MPEG Video Group,named as joint video team(JVT).H.264 greatly improves coding efficiency and will be a new international video coding standard. With the swift and violent development of compunication technology, digitized technology is influencing daily life more and more deeply. The demands for information of people have already been not merely confined to the traditional telegram telephone service , even such data as file transfer , E-mail ,etc.; The business can't already meet people's diversified demands either, what people expect now is that more high-quality multimedia application service in video , picture , sound , characters. However, digitization has put higher demand to bandwidth ,memory capacity of data transmission etc. while meeting the demands of people. To the information of the multimedia especially to picture data and video data, this kind of situation is more serious, for example propose according to CCIR601 ordinary TV signal of quality digital one yard of rates of video is about 216Mbit/s, more high-definition TV HDTV is above 1. 2Gbit/s.So study and develop new-type effective picture to compress code and decoding method is the best settlement ways to store and transmit these data in the form of compressing. Since the end of the forties of the 20th century, picture code technology already passed by the development course for over half a century. From the discussion of the basic method during fifties to sixties, the research of the early videophone to the seventies make this field get considerable development, a lot of basic thoughts and methods are all proposed in succession. Around the eighties , complied with the informationalized main trend , faced various kinds of development research that used to launch in a more cost-effective manner. After entering the 1990s , a series of pictures and compressed standard of the code have successively made in the world, such as the compression code standard JPEG and JPEG2000 used in static picture , the MPEG-1 , MPEG-2 , MPEG-4 that used in videos stored and transmitted, and the H. 261, H. 263, H. 26L standard that for video conference and videophone,etc. H. 264 / AVC is the newly encode standard that made by ITU-T and ISO/IEC together, it was proposed in 1997 by VCEG of ITU-T at first, the goal is to proposes a kind of high performance (compared to at that time H. 263)Video encode standard. Compared with some previous code standards, H. 264 has inheritted the advantage of agreement of H. 263 and MPEG1/2/4's video standard, but not changed more at structure , just use some advanced technology inside the module in each main function that improved the code efficienly. It shows mainly: The code no longer based on 8×8, but carrying in size 4×4 that code incomplete varily. No longer adopt vary code way DCT too, but is integer vary code. H.264 adopted the context adaptive binary scale arithmetic code (CABAC ) with higher efficiency, there is a difference in the quantization course that corresponding with it at the same time . H. 264 has adopted a lot of new technologies in sports estimated, include variable piece big or small , many frame sport estimate , inferior picture element sport of precision estimate etc. mainly. H. 264 standard has many advantages ,such as simple algorithm and easy realized, highly operation precision and not overflow , fast calculate, taking little memory , slack pieces of effect ,etc., it is a kind of more practical and more effective picture code standard. The characteristic of H.264 standard can be concluded mainly into three aspects. It is more Practicable,more adaptive to IP net and mobile system and it improves the key components of coding structure based on hybrid video coding framework. For example,it adds coding mode decision,multi frame Prediction,context-based adaptive variable length coding (CAVLC),4×4 integer transform, loopfilter,etc. The improvement in performance leads to higher computational comlexity in the new standard.The complexity of H.264 encoder 15 about 3 times of H.263 encoder and the complexity of its decoder is 2 times of H.263 decoder. The optimization of H.264 codec is important for its application in different fields. These characteristic can accelerate multimedia application undoubtedly ,...