MPEG-4的可伸缩视频编解码技术研究

回顾了目前的网络视频流服务，提出基于MPEG-4的可伸缩视频流服务。研究了其中的关键技术：利用MPEG-4的可伸缩码流，编程实现了MPEG的可伸缩解码。分析了在服务器端的MPEG-4的可伸缩编码依据时域可伸缩(即时域分辨率的变化)、空域可伸缩(即空域分辨率的变化)和对象的可伸缩(主要和次要对象的取舍)三个概念，对MPEG-4数据流进行分层，保证图像基本质量的为基本层数据，其它的则为各增强层数据，起着改善图像质量的作用。相应地，用户端也需要可伸缩解码器的支持，它能在收到完整的一层或几层数据后正确、快速地解码。

Study on Scalable Video Coding Techniques in MPEG-4

This paper surveys current situations of the network stream services,then a novel network stream service based on MPEG-4 is proposed.The key technologies are:based upon the above study and analysis,the author designs and implements partly scalable MPEG-4 stream service..In the server side,scalable MPEG-4 coding includes temporal scalability,special scalability and object scalability.The MPEG-4 data is then divided into several layers.The base layer provides the basic quality of the video objects and complies to the lowest network bandwidth requirement,while the enhancement layers provide better quality.Accordingly,the scalable decoder can decode one or several layers properly for the client.