中文摘要：

在异构的网络环境下，如何自适应地传输满足多种终端设备和不同用户需求的视频内容具有重要的意义．以达尔文流媒体服务器为实验平台，提出一套基于运动强度的视频自适应传输策略．在服务器端通过检测丢包率来控制发送速率等级，避免网络拥塞，并采取一定策略消除因丢帧而产生的马赛克；在自适应策略中加入了运动强度信息，针对不同的运动强度级别进行不同的处理，使得综合视频质量得到提高．实验结果表明，文中的自适应策略不仅可以避免网络拥塞，而且可以改善视频播放质量．

英文摘要：

Adaptive video transmission is dedicated to deliver video content over dynamic and heterogeneous networks and devices. Using Darwin streaming server, a set of adaptive strategy is proposed based on motion intensity. To avoid network congestion, the sending rate level on the server is controlled by detecting the packet loss rate in real time. To eliminate the mosaic effect brought by frame dropping, an algorithm of certain P frame dropping is proposed. As for different motion intensity, the video quality is different when the frame dropping rate is same, so the motion intensity descriptor from MPEG-7 standard is introduced to the adaptive strategy as a parameter. Experimental results demonstrate that the proposed strategies can not only improve the overall video quality, but also eliminate the mosaic effectively.