when I try to edit my viedo (mpeg) I am not able to see over 8 min of viedo on the in either mode ( timeline, storybook, etc) I am only able to edit 5 clips but can not see anymore of the video to edit more. Could you please tell me why. PS I am new to this program and video editing i general.. so you may have to explain it as if you are talking to a 30 year old