Design And Implementation Of AVS Video Real-time Transport System

AVS (Audio Video coding Standard) is the image compression standard with independent intellectual property rights. Compared to other international video coding standard, AVS video standard has advantage of high encoding efficiency, easy for implementation, low patent fees and so on. With the fast development of streaming media technology, it is significant for the promotion of AVS to combine AVS with streaming media technology.Based on analysis of some protocols concerned with streaming media technology and the structure of AVS video bit-stream, an AVS video real-time transport system is designed and implemented. First, some pivotal problems of AVS video transporting based on RTP (Real-time Transport Protocol) are researched and solved.When dealing with th original AVS video bit-stream, it is converted to AVS NALU (Network Abstraction Layer Unit) stream , which can get rid of encoding details for the network. When packaging the NALU with RTP, it constructs three different kinds of RTP payload format: single NALU, Compound NALU and Fragment NALU. If an NALU is too large, the size of a packet will be not larger than the max transport unit of IP network by using Fragment NALU, and if an NALU is too small, it will reduce the network load by using Compound NALU. When sending the RTP packet, it controls the sending speed according to the stream frame rate and the RTP packet payload format, thus to reduce jitter of the client.The system is composed of server and client.The server side can be divided into three modules: session control, dealing with the AVS video, RTP packet encapsulation and RTP packet sending. It designs three buffers to process the video data which can reduce the complexity of the arithmetic. The client is divided into three modules too: session control, RTP packet receiving and decapsulation, constructing NALU and stroing. It designs an arithmetic to adjust the size of the receiving buffer dynamicly and uses relevant manage method to manage the buffer, which can resolve the problem of packet loss and disorder. The experiment results show that the AVS transporting system works correctly.