What screen size is your player?
Try downloading viDrop from this site here:
http://mympx.org/forum/video-related/38838-vidrop-free-open-source-converter-rockchip-players.html
Then use the setting of
320 x 240 and see if that plays on your player. The resolution is important as generally the players will only accept a certain w x h resolution for it to play on your player.