Study Of Packet-loss Resilience Technology For H.264 Video Transmission Based On LDPC And Fountain Codes

With the progress of the computer, communications, network and multimedia, video communication receives much recognition as a basic component of the multimedia communication. H.264 uses kinds of efficient coding algorithms which induce the compressed data sensitive to the packet-loss, so the packet-loss by the practical IP channel may lead to a substantial reduction in the reconstructed images quality, and the error may also have a bad effect on the following reconstructed images. Therefore, the research on the effective packet-loss resilience methods to ensure the video transmission quality is of great importance in both theory and practice. Because of the inherent imbalance character of the weightiness distribution of the video information, different part of the image and video coding acquire different QoS, and can make different contributions to the rebuild of the image. For the inherent character of the image and video data, an Unequal Error Protection (UEP) algorithm bases on channel coding is a better method.This thesis first introduces the erasure channel and some kinds of erasure codes, and then emphases the encoding and decoding theorem, and the degree distributing function of the LT code which is the first realized fountain code and then introduces the Raptor code. Secondly, it describes two kinds of UEP algorithms and then does the simulation experiments and analysis separately. One kind of UEP algorithms is the LDGM Triangle Unequal Error Protection algorithms (LDGM Triangle-UEP algorithms)which is combines the data partition (DP) of the H.264 with the LDGM (Low Density Generator Matrix) Triangle coding . Another kind of UEP algorithms is the advanced Luby Transform Unequal Error Protection algorithms (LT-UEP algorithms) which improves the mechanism of the degree value assignment of the encoding degree distribution function. On the basis of above analysis and research, this thesis proposes an Unequal Error Protection scheme cascades the LDGM Triangle-UEP algorithms and the LT-UEP algorithms to better protect the high priority data. The result of the simulation experiments shows that the proposed scheme can increase the decoding success ratio on the same encoding redundancy and decrease the demand of the redundancy on the condition of the same decoding success ratio. The proposed scheme can effectively recover the lost data and improve the subjective and objective quality of the reconstructed image with limit redundancy. Moreover, it has low coding and decoding complexity and more suitable to the unstable channel.