| The traditional video compression standards, such as MPEG and H.26X, have a farmore complicated encoder than decoder and the encoded video data is highly sensitiveto information loss and channel bit errors. Recently, the newly occurred sensor networkand mobile devices for wireless video transmission need a simple and robust encoder.However, the traditional standards can not meet these application's requirements. Basedon the Slepian-Wolf distributed lossless coding theory and Wyner-Ziv distributed lossycoding theory, distributed video coding(DVC) proposed by the scholars around theworld provides a new solution to those problems and is being studying widely.The rate control algorithms affect the performance and applicant environments ofDVC greatly. Base on the introduction of DVC's theoretical principle, properties and thetypical architectures, an encoder rate control model(ERCM) for DVC is proposed andhence a DVC system without feedback channel is implemented. And then, we study theframe bitrate allocation(FBA) based on rate-distortion optimization(RDO) andWyner-Ziv frame bitrate allocation(WZBA) based on unequal error protection(UEP) indetail. The FBA calculates the optimal allocation factor in each GOP(group ofpictures)according to the requirement to the quality of decoded video. The WZBAallocates the Wyner-Ziv frame target bitrate to different coefficient bands, and designsbitplane rate control oriented LDPC check matrixes for the bitplane UEP in eachcoefficient band.The experimental results show that the propose ERCM can improve DVCrate-disdortion performance by 1 dB, and can also adjust the bitrate allocation schemefor different video quality. Therefore, the ERCM are more flexible and can be used inpractice... |
PDF Full Text Request