Research On Scalable Video Coding And P2P-based Video Transmission Techniques

With the development of both Internet and video coding techniques, video applications over Internet have transformed our lives through the way we communicate, such as video conference, video on demand (VoD), video monitoring service and so on. On the other hand, it will face some new challenges on video compression and network transmission over Internet. Firstly, the fluctuatation of bandwidth, packet loss and code error happen frequently due to heterogeneous networks and uncertain quality of service (QoS). Secondly, video compression for streaming should be adaptive on QoS to satisfy people's different requirements on quality, delay and interaction. Thirdly, video compression should support different decoder capacity and different requirements of play back functionality; it is because different clients have various network access capacity and video decoding capacity. Finally, according to the current status of network healthy and special requirement of application service, the best transmission mode should be chosen to guarantee the requirements of delay and reliability during the video data transmission.All these factors require the cooperation of video compression and network transmission to satisfy different needs of streaming applications. The newest scalable video coding (SVC) scheme based on H.264/AVC and the P2P-based video transmission techniques are most two promising ones. In this thesis, we investigate some new algorithms of these two techniques: 1) spatially scalable video coding algorithms, in order to improve prediction precision, investigate the upsampling filter design, in order to extend the inter layer prediction technique, study the intra coding method for spatial enhancement layer. 2) The P2P-based video transmission scheme. In order to handle the problem of P2P video transmission in the asymmetrical speed channel, study the fast video transmission algorithm in the case of multiple service nodes to single request node. The main contributions of this thesis are as follows:First, the basic theoretical knowledge of video coding and video transmission is deeply introduced and described, which involves traditional video coding, scalable video coding techniques and video transmission networks, protocols and performance parameters. Second, at the aspect of spatially scalable video coding, a simple and efficient image component adaptive upsampling filter scheme in SVC is proposed. In order to increase coding efficiency of SVC, proposed scheme utilizes the basic characteristic of human vision system and differentiates image components. Considering both computational complexity and interpolation precision, it assigns the most suitable upsampling filters for interpolating different components. Experimental results of all testing video sequences show that proposed scheme causes negligible decrease on coding performance and reduces a lot of computational complexity.Third, at the aspect of inter layer prediction technique in SVC, an efficient enhancement layer scalable intra coding algorithm for spatial scalability in SVC is proposed. According to the coordinate attribute of the macroblock to be coded, proposed algorithm makes use of both enhancement layer data and base layer reconstructed data, and chooses the best data combination for intra prediction. Especially, at the case of that the enhancement layer data is not available, base layer reconstructed data is used as predictor instead for intra prediction, which extends the implementation of intra coding under this special situation. Experimental results show that some visible improvement of coding performance is achieved with almost no changes on computational complexity.Finally, at the aspect of bidirectional speed mismatch faced by video transmission in the asymmetrical network environment, a point to multi-point based dummy symmetrical speed video transmission algorithm is proposed. It groups up the video data packets from several source nodes and simultaneously sends them to the destination node, which makes the bidirectional speeds match approximately. Simulation results show that proposed algorithm can increase the utilization ratio of network bandwidth and also reduce the transmission past time of video data packet.The research work involves the techniques in both video coding and transmission domains; therefore, it has important theoretic and practical significances.