linux音频编程，通过对声卡的操作，实现录音，回放的功能。-linux audio programming, through sound card operation, to achieve sound recording, playback functions.

linux音频设备驱动的mixer和sound的测试程序，mixer混音对频率调节，sound先录音在放音-Linux audio device driver mixer and sound testing procedures, the mixer mixes the frequency adjustment, the first recording sound playback