To bring videos or files from your PC to your iPhone simply use a cloud based service. Such as Dropbox. To bring files, uncompressed, simply log into your Dropbox (or other cloud back up service) on your iPhone or download the app for it. This will ensure you're able to get the highest quality video onto your iPhone. You can also use iTunes to bring videos or photos in your account onto your phone.
You can find more information here via Apple.