| While developing of video international standards compression and encoding technology, a series of video compression come on one after the other, and the video multimedia data are widely used in many fields. Because IP network has some inherent characters such as delay, transmit error, packet loss and bandwidth fluctuation, it can only afford best-effort service, but cannot offer Quality of Service (QoS) guarantees for the real time video stream transmission, which is a great challenge to video compression coding. On the other hand, the heterogeneity of the networks and the variety of terminal equipments make it hard to transmit video stream generated by traditional storage-based video compression coding, which tries to improve the coding efficiency and get the optimal video quality in a fixed bit-rate and is not adapt to transmit in the Internet because it cannot work in an efficient and flexible way according to the bandwidth utility and QoS guarantee. So it is necessary to find a new video compression coding and transmitting method that is suitable for the IP network and network-based scalable video coding meet the requirement to some extent. The thesis focuses on several key techniques of compressing video compressing takes full study and brings some improvements.Firstly, the thesis summarizes the knowledge such as the principle of video compressing, key technology and the criterion of coding. Afterwards, the thesis analyzes the technology of fine granularity scalability, such as its conception and arranges several coding methods of video compressing. Subsequently, analyzing some problem of FGS coding and aiming for its defect, we present an improved FGS, which chooses high quality reference in enhancement layer coding and uses the leaky prediction techniques which can control error propagation by the leak factor η(0≤η≤1).In this way the error can be recursively attenuated for all the past frames and improves the video quality. In our own test video coding scheme, the experimental results shows that the algorithm improve the coding efficiency about 0.3dB in the low and middle bit-rate range. Thirdly, we analyze and implement the progressive fine granularity scalability (PFGS) and further discuss the macro-block based PFGS. In order to improve the resilience and robust of PFGS enhanced layer bit-stream, we introduce some resilient algorithms used in MPEG-4 to PFGS enhanced layer coding. We also use Universal VLC (UVLC) in the coding to limit the transmit error in a few blocks because of its excellent self-synchronization property. At last, we present some proposals in scalable coding. |
