Plays sound but not the actual video

I see that everyone has a sound problem on here but am I the only one who has the problem of the video's sound playing but not the actual video?

I just converted my videos to ipod format and when i tried to play them on my ipod I just got the sound of the music video and just a picture of the beginning of the music video. Nothing moving. Can someone please, please help me? this is fustrating me, I appricate your help, thank you