When you watch some of the mp4 movie then you might hit a problem that the audio and video go out of sync. Meaning that when the sound is ended but the mouth in the video still moving.
Something that you do like me is completely useless such as:
1. Download K Lite Codec.
2. Download VLC media player.
Someone suggested the following:
3. Download latest driver (might help).
4. Download DirectX
One thing you should do first and it works for me:
1. Download the DivX codec and player here http://www.divx.com/
That works well for me.