4s videos look great but don't play smoothly in QuickTime or iTunes on Windows

[dslide]

I use iPhone 4S with IOS 5, and a PC with Windows Vista. I transferred videos by dragging from the phone device to a folder on the PC. When I play the MOV files in either QuickTime 7.7 or iTunes 10.5, the image jerks or repositions every 1-2 seconds. This doesn't happen with my old 3G videos. What can be done about this?

 

[Rocko]

How old is your computer/video card? I notice my comp has trouble with the 1080P videos from the 4S. Even videos posted on youtube.