Any way to convert HD into mp4 (for iTunes) without losing quality?

[*LTD*]

Silly question maybe, but I don't have a lot of experience in this area.

I've got a few HD movies - 1080p and 720p x264 format. I'd like to watch them through iTunes, that is, to add them to my iTunes library. I believe at this point iTunes only does mp4.

Do I have to convert these movies? Is there any way to convert them to mp4 without losing HD quality?

Thanks!

 

[TEG]

x264 is just the free version of h264, which is part of the MPEG4 standard (both mp4 and m4v). Simply drag the files into iTunes to check if they will play. Unfortunately, iTunes only supports iPod/iPhone and TV video sizes, which will loose quality, but if iTunes won't play the x264, try ffmpeg or another video converter to convert from x264 to h264 (which I don't believe it to be necessary).

TEG