uga
Try my tutorial found here.
http://www.mympxplayer.org/how-to-vt3183.html
Let me know how it goes, I also have a rockchip player and have overcome the problems your having now. The #1 problem is to insure to use MP2 audio not MP3 with the Xvid MPEG-4 video format. PM me for any further assistance.
Dave