i need a quick/Urgent Help

i want to to convert a mkv file (it contains 1 video, 2 audio stream and 1 subtitle stream) to mp4 file (vcodec h264 acode AAC) which will include both audio stream and also the subtitle stream.

I am interested to use ffmpeg but if not possible then i can also use Mencoder. but please some one help me out will the full commanline help..

please it is a kind of urgent

best regards
kamrul hassan