| With the rapid development of the network technology, the wireless technology and thecomputer hardware technology, various multimedia technologies are pushed into human'swork life and family life, such as DTV, mobile TV, IPTV, teleconference, etc. Conventionalvideo standards, such as MPEG-x and H.26x, adopt the MC/DCT based hybrid structure.Henceforth, the complexity of the encoder is 5-10 times as that of the decoder, which isappropriate and necessary in multimedia applications which encode once and decode manytimes such as video broadcasting and VOD applications. However, various kinds of new mul-timedia applications emerge, such as wireless VSN, wireless PC cameras, mobile camera-phones, disposable video cameras and camcorders, etc. Some use the battery to provide theenergy, while some are disposable. So they are all constrained largely in the power, memoryand computing capacity. And henceforth the simpler encoder is needed in the aforemen-tioned multimedia scenarios to save resources. The time-consuming ME/MC procedure isshifted from the encoder to the decoder in the DVC, and the simpler encoder is obtained. Thethesis researches on several key problems in the DVC, such as the compare analysis of twoSlepian-Wolf coding techniques, the refinement of the virtual channel, the efficient S framegenerating method and the rate allocation in different regions of the D frame. The noveltiesof the thesis are as followings:The syndrome approach and the parity check approach emerge as two practical Slepian-Wolf coding techniques. In the thesis, performances of these two approaches are comparedfrom two viewpoints. One is the comparison of their error correction capabilities usinglinear block codes; While the other is the comparison of their decodings using LDPC codesspecifically. Moreover, we prove that if the parity check matrix has the nested property, theparity check approach will achieve the optimality.We extend the Wyner-Ziv problem to the coding of multivariate Gaussian source withmultiple Gaussian side information at the decoder. The achievable region is obtained, and itis easily extended to the case that the difference between the source and the side information is multivariate Gaussian, no matter what distributions the source and the side informationare. This introduces the rate allocation problem into the DVC, which can be solved by areverse water-filling method. The multivariate Gaussian Wyner-Ziv coding prototype is thethesis's important theoretical foundation.A novel and efficient Side-Information Frame Generator (SIFG) is proposed, whichconsiders smoothness constraints of both the motion vector field and spatial adjacent pixels.First, two adjacent decoded Intra frames at the decoder are used to perform the block basedMC-I, so as to obtain the motion vector field of the current S frame. In the second step, thedirection angle of the motion vector is uniformly quantized, and then the smoothing filter isused to smooth quantized direction levels among motion vectors of adjacent blocks. In thefinal step, the pixel-wise smoothing operation is used to mitigate block artifacts furthermore.Simulation results show that the proposed techniques provide potential rate-distortion per-formance advantages to the MC-E method. Besides, the fine visual quality of the S frame isobtained. Especially, the proposed SIFG method can be compared with the IPME algorithm,and even performs better in following video scenarios such as approximately linear motionscenario, dialogue scenario and video monitoring scenario.Adopting the edge detection algorithm, the S frame is divided into regions with differentcharacteristics, and hence the virtual channel is refined into the multivariate Gaussian Wyner-Ziv coding model. In different regions, different quantizing and puncturing strategies areapplied accordingly. Simulation results show that around 1.5-2 dB coding gain is benefitedfrom the refinement of the correlation model. Meanwhile, the simpler encoding character isremained.
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