在嵌入式音频流媒体播放系统中,音频流媒体服务器作为核心部分发挥着至关重要的作用。结合局域网音频流媒体播放系统实时性要求高和终端缓存资源很有限的特点,提出在服务器端发送速率动态控制算法。发送速率动态控制算法主要是先保证在尽量小周期内的平均发送速度等于理想发送速度,然后再通过负反馈因子微调这个尽量小周期内局部的发送速度。在使用上述技术的基础上,点到多点播放同一节目时多播表现出来的数据同步性不理想,为提高服务质量,在服务器端进一步选用对等工作组模型以及单播轮询发送方式。实验结果表明,播放终端的流畅实时播放和同步性最终得到了保证。
In embedded audio streaming media system,the audio streaming server as a core part plays a crucial role. Taking features that high real-time requirement and limited cache resources in a LAN of audio streaming media system into account,the server presents dynamic transmission rate control algorithm. It firstly ensures the average transmission speed is same as the ideal sending speed in as soon as possible cycle,and then uses negative feedback factor to adjust partial speed in this cycle. Data synchronization is not good enough when uses multicast broadcasting the same programs in point-to-multipoint structure. In order to improve the quality of service,the server selects peer workgroup model and unicast polling transmission mode. Experimental results show that the real-time and smoothly broadcasting and synchronization for terminals can been ensured.