Streaming video really requires a huge amount of data to be transmitted. If you have a slow Internet connection, your computer will play the video faster than your Internet connection can download it. Consequently, it will stop and jerk and be an all-around bad experience. Here is how to solve this problem. When you start the video, you should see TWO lines gradually moving from left to right. One is the video itself and tells you how long it is and where you are now. The second line (it may be a different colour) is an indication of how full the buffer is. The video is downloaded into a storage buffer on your computer and is played out of that buffer. If you immediately pause the video (the button with the two vertical lines), then wait till the buffer is completely full, then start (the button with the arrow), the video will play nicely.