Research And Applications Of Digital Video Transcoding From MPEG-2 To H.264/AVC

With the development of the Internet technology, people want to transmit not only word and sound, but also video information. The digital video technology has developed quickly in order to transmit video in high quality. Because many kinds of video coding standards are used, it is a problem to transform different format of the program. Video transcoding technology is the key method for solving such problems.Video transcoding has been applied in new area for new video coding standard. In this disertation, the overview of transcoding is presented first. Some transcoding structures are described and analyzed. Then two video standards, that is, MPEG-2 and H.264/AVC are studied in chapter 2. The difficulties in transcoding from MPEG-2 to H.264/AVC are pointed out and mode decision and motion estimation are investigated. Some algorithms for transcoding are proposed in Chapter 3 and 4. The experiment results show that the proposed algorithms have little loss in video quality and remarkablely increasing in transcoding speed. It is suit for transcoding applications.In chapter 5, two transcoding applications in DTV are dealt with. One is logo inserter and the other is seamless splicing for transporting stream. The rate control algorithm of logo inserter controlls the output element stream accurately and ensures the output frame length close to input frame length. Two algorithms on seamless splicing are provided. One is based on system layer. The other is based on video element stream. They can both splice two transporting streams seamlessly. The first one possesses less calculation and higher speed characteristics. The second one can splice more accurately.In chapter 6, multiplexing and re-multiplexing technology are examed. The multiplexing algorithm is in accordance with T-STD. The efficiency is improved and the bandwidth is saved. The re-multiplexing algorithm is researched for logo inserter. It is based on some special structure of logo inserter. So the calculation is decreased and operation speed is high. As a result, less system resource is used.This disertation is mainly concerned with the transcoding technologies from MPEG-2 to H.264/AVC and transcoding applications in DTV. Some algorithms are proposed and verified by experiments. The algorithms are efficiency and some of them have been used in practice.