Usually we have many HD movies in our computer, but we want to see them by our mobile phone. This requirement produces some questions: 1?the HD videos are too big to transfer to phone timely and it it hard to play on phone smoothly, so we have to transform the videos smaller and fit the screen of phone. 2?the coded format of the videos are varied, but limited types are supported by mobile phone, so we should transform the coded format to those supported by mobile phone. I've leaned the streaming media fit this problem, what I want is: 1?are there any good opensource projects fit this(ffmpeg?live555? darwin?)? 2?are they quick enough to transform coded format and transfer to mobile phone to play with no delay? Thank u very much!