When im downloading video and i preview it, i can watch whatever Im downloading. But when it is completely finished , Im only able to watch a portion until the time bar at the bottom runs out. I know there is more to see because i saw it earlier in the preview. Sometimes, if i mess with the bar and click it back to the beginning before it totally runs out, the video will continue until i have to repeat the process 6 or 7 times to enjoy the entire film. Whats going on?