how bout plugging the 3.5mm earphones directly to the jack? if it doesn't have any sound, that means sound codec not supported?
solved the issue. i made a mistake that the 3.5mm works, actually it did not, and speakers also not. it is the app (BS Player) that got issue with that file. I installed VLC again(previously I got it, but removed coz it lags when playing certain files) and everything works well.
I still not used to Android......

