With the development of science and technology, people have higher requirement to video monitoring. This paper proposes a mobile audio and video monitoring system based on Android platform. In this system, we adopt Mediastream2 to process the stream media, implement the safe and reliable transmission of stream media with ORTP and codec of audio and vedio with FFMpeg. This paper mainly introduces how to encode and decode the audio and video with the FFMpeg, a kind of audio and video library and output audio and video synchronously. Finally, the real-time video monitoring testing can be realized on the embedded platform TQ210.