Actually i had few video which when played with latest mplayer appeared monochrome like a classic . Then i changed video output to x11 & video was well in color. But on pressing f
the frame did not stretch but just black bands around video of original resolution.
Stubborn , as I am .
I decided to play video with same aspect ratio covering maximum part of screen & subtitles in empty area not overlaying the video frame.
mplayer -vo x11 -vf scale=width:height,expand=0:-remaining space in vertical:0:0
Here width & height are same multiple of original resolution.
remaining space in vertical screen=600-height if your screen resolution is 'somethingx600'.