Abstract: The wide application of audio-video technology is becoming more and more popular,involving the development of multi-media players for terminal mobile,video conference,digital television,video on demand software,etc.This paper first studies the structures of audio and video systems and analyzes each layers of them;then based on the developing platform Android,this paper expands the audio-video system by transplanting the FFmpeg framework,enabling it to support the parsing and decoding of a variety of media formats (audio and video).At last,this paper proposes the multi-media player development scheme by adopting the expanded audio-video system.