A Big Problem

It's urgent. I use MediaRecorder to record audio and it will release a .3gpp file. Then I use MediaPlayer to play the audio which is just recorded. The quality is poor. It is played at half speed. if I record 10s, it will be played 19s. I don't have a device so all the operation is did in the emulator. Why could that happened? It seems that others don't have the problem. How to deal with it.Thank you very much.