Why my mp4 can't play video music
Even thought it said that it can play video music
And I lost the disk that go with my mp4
What can I do now?

I think the video codec is wrong, and I think u can try Foxreal Video Converter to solve this problem. It can convert your video to mp4 with the correct codec for playing. With its advanced audio and video sync technology, u can get the best enjoyment. U can try it. Good luck!