Abstract: An adaptive streaming media scheme is presented, which adjusts the transmission rates and bit-rates of video streams according to network environments in order to enable video data to be transmitted to clients and client players to display media data in time. The scheme includes several function modules such as rate shaping, congestion control and video quality adaptation, and the relations among them. Algorithms in each module can be flexibly selected and implemented, which enhances the flexibility and scalability of the scheme. So the scheme doesn’t depend on specific video encoding standards and network protocols. The application of the scheme based on a practical media streaming server is also presented. And experiments prove the effectiveness of the scheme.

Key words: Streaming media; Rate shaping; Quality adaptation; Congestion control

摘要： 提出了一种自适应流媒体传输方案，根据网络状况调整视频数据的发送速率和视频流的码率，以保证视频数据顺利及时的传输到客户端，使客户端能够顺利进行高质量的媒体播放。该方案涵盖了码率整形、拥塞控制和视频质量自适应等功能模块及其相互关系，各功能模块可以依据应用需求选择算法加以具体实现，从而提高了方案的可扩展性和灵活性。所以该方案不依赖于具体的视频编码标准和网络协议，适用范围较广。文中还基于实际流媒体服务器给出了该方案的一个实际应用，点播测试实验证明该方案是有效的。

关键词: 流媒体；码率整形；质量自适应；拥塞控制