零拷贝技术在实时PCM捕获中的应用

Application of Zero-Copy In Real-time PCM Capture

采用各种编解码的音频数据在被写入声卡设备之前会被解码成PCM格式。在某些情况下,音频数据在被解码之前处于加密状态,所以只有通过捕获声卡中的PCM数据才能获得这些解密后的音频数据。由于音频信息具有对延迟敏感的特点,本文提出了一种基于Linux操作系统的高效PCM数据捕获机制,即利用网络缓存中常用的零拷贝技术,提高PCM数据的捕获效率。

audio data using various codec is converted into PCM format before written into sound card. Especially in some cases,audio data is deciphered by applications until written into sound card. Thus,capturing PCM stream is the only method to obtain audio data. Given audio data is often delay-sensitive,in this paper,an efficient mechanism based on Linux is proposed,which applies zero-copy technique generally used in web cache,to enhance the capture efficiency.