通过麦克风录音，然后把pcm流压缩成mp3格式的文件-Sound recording through a microphone, and then the pcm stream compressed into mp3 format

可以实现录音，并存在sd卡上，可以对其进行播放删除-Can achieve the recording, and on the sd card, its playback to delete

用android中的MediaRecoder类编写的录音的源码，可以用来测试底层是否支持音频录制，在android底层问题排除上很重要-Android written in MediaRecoder class recording source, can be used to test whether the underlying support audio recording, excluded the underlying prob

audiorecoder实现录音放音。可以证明，放音的时候是可以录音的。- audiorecord achieve recording playback. It can be shown when playback is recording.