video player : how create a size and quality selector

hi want create a 3 button to change video dimension "full screen","dimension2","dimension3" and a quality seletor button to change video quality playback  without start the video to the begining but from the current position as youtube....

for the video i have encoded a video in this resolution 1280x720, 640,360, 320x180.....

i have video1280,video640, video320...

thanks in advance