A Research On Video Coding Technologies For Communication

Video Coding is one of the key technologies of multimedia communication. Themajor task of the video coding technologies for storage-based applications is how toimprove the coding efficiency. However, for video communication applications,besides the requirements on higher coding efficiency, the generated bitstreams haveto adapt to network bandwidth variations and tolerate transmitted errors (such aspacket losses in the Internet network and random or burst errors in wireless network).The goals of the video coding were changed from the storage to the transmission, andfrom the fixed bitstreams to the scalable bitstreams. The video coding technologiesfor communication applications are the key question for video communicationapplications. It is important to research these technologies for the video codingtheories and the engineering applications. The thesis systematically researches thevideo coding technologies for communications. The main work is as follows:(1)　In order to solve the low coding efficiency problem of the fine granularity scalable (FGS) coding in MPEG-4 standard, a universal scalable coding framework based on FGS is induced, and on the basis of this framework, a macroblcok-based fine granularity scalable video coding with leaky prediction (MB-based FGS-LP) is presented. A leaky prediction INTER mode is first proposed for the enhancement-layer macroblock coding. Then, a decision-making mechanism is developed to choose the coding mode and the optimal leaky factor for each enhancement layer macroblock. Our simulation results demonstrate the proposed scheme can provide further coding efficiency improvement over the MB-based PFGS scheme, yet still keeps the property of the error recovery.(2)　In this paper, a new method based on the JPEG2000 bit-plane coding idea is proposed for the enhancement layer coding of FGS, referred to as Embedded Block Coding Based on DCT (EBC_DCT). In EBC_DCT, the data redundancies between the residual DCT coefficients are eliminated by context-based arithmetic coding Experimental results show the proposed method is higher coding efficiency than that of the original FGS enhancement layer in MPEG-4.(3)　Based on the properties of the FGS bitstreams, a layered FEC framework is presented. To reduce the use of the bandwidth, the FEC data is separated面向通信的视频编码技术研究 two or more layer. The sender decides how many layers are sent according to the feedback statistics after a period of time. Moreover, an adaptive error concealment method is applied to the enhancement layer of the FGS in the decoder. Our experimental results show that the error resilience ability of the FGS bit-streams is obviously improved in the bit error environment.(4)　Three-dimensional (3-D) wavelet coding using a motion compensated temporal filter (MCTF) is emerging as a very effective structure for highly scalable video coding. This paper describes a video coding system based on motion compensated 3-D wavelet coding, referred as MCL-3DWT. In the new system, the motion compensated temporal-filtering process is achieved in terms of the concept of lifting filters. The coding efficiency is improved due to the use of multiple-reference and subpixel accurate motion compensation. The proposed video system is applied to several test video clips. Its performance exceeds that of MC-EZBC while maintaining SNR, temporal, and spatial scalability.(5)　Lifting Scheme is an efficient method for construction of wavelet after multiresolution. This paper constructs a kind of lifting 9-7-tap wavelet filter for hardware implementation, called D97, which not only have excellent compression performances but also are very suitable for the implementation of ASIC. The computational complexity of the new lifting wavelet filter is enormously reduced because of the introduction of the s...