一个负载自适应的实时音频播放算法

A Load Adaptive Real-time Audio Playout Algorithm

研究了Windows操作系统中网络电话软件的实时播放音频的策略。在非实时系统中,音频播放程序不能严格地被定时执行,播放缓冲区被耗尽而产生播放空隙。采用DirectSound技术,以ms为单位来控制音频的播放,并根据负载的变化动态地调整每一个话音期的门限值来减少播放空隙。实验结果表明,该算法能够以较小的时延为代价来获取平滑的播放效果。

A real-time audio playout strategy for Intemet phone tools in Windows is proposed. On a non-realtime system, the time interval between two instances of the audio playout thread being scheduled is not strictly equal, the audio output buffer exhaust then gaps of slience are produced. DirectSound is ultilized to control the playout at the granularity in millisecond level, an threshold is adjusted for each talkspurt based on the current load. The experiments show that this algorithm is able to reduce the slience gaps significantly at the cost of a small latency.