AVAudioRecorder + lame Mp3 Encoder
##This demo shows:
1.Choose the audio format (MP4AAC, PCM, LoseLess …. )
2.Change the output, Speaker or mic( ear pod ).
3.Convert the Linear PCM To Mp3
##Reference:
https://github.com/wuqiong/mp3lame-for-iOS
http://www.cocoachina.com/bbs/read.php?tid=82730&keyword=lame
http://stackoverflow.com/questions/1022992/how-to-get-avaudioplayer-output-to-the-speaker