Write an Android application

Hi there, We need a audio and video mixer for our game which works with Unity as a plugin. The user should then have the possibility to upload the video to facebook. What we expect: In Unity3D Unity4.6.6 android, In unity scene, multiple audio files which can be mixed with main movie file at various timeline it should generate on video file - mp4 (we don't need other formats ). it can be saved in sd card, from which it can be played back in the game. it would be great if it works also with android versions which are also smaller than Android 4.3. Only use licence free or open source code/software. Extremely simple to implement in our project. I think it should be possible to do such a function if you integrate ffmpeg to encode the video. This is a project which needs good skills in Unity Android and ffmpeg (if needed). The project can be started as soon we have somebody who realize this project. Thanks and have a great day