I have an iphone 4 running 4.2 and my videos are choppy, they were choppy before I update also. I have updated my computer to everything that I can find, but Im not very knowledgeable. Please help me I would appreciate your guys expertise opinion.
When you restore an iPhone Apple will not be able to see that it was once jailbroken.
If the videos play 'choppy' on the computer as well then there is a problem with the encoding most likely. Try new videos codecs or re-encode. Have you tried VLC Player?