A friend of mine has emailed me videos and when I try to download them using my unlocked/jailbroken iPhone 3gs it let's me download the video but it will not play. I notice that all the other movies and videos that I download have letters, numbers, or names, etc... Identifying them as a file but at the end they say mp4. The videos that my friend sends me do not say that. Is that the problem, and if so what do I do? Also, u must know that theses files are fairly big at approx 200mb and my friend had to use a sight that sends large files to send them to me like dropbox. If u can help me or point me in the right direction it will be greatly appreciated. Thank you very much!