Videoplayer Lag

Hi, i tried to download a video from a server and play it on unity.
I download the .mp4 file and put it in the Application.persistentDataPath folder, i put the url in the videoplayer.

The problem is:
The video lag, what can I do to solve it?

No one can help me?

please i need help, the video lag with android, i have to stop woking with unity?? :S