MPEG-4 is rapidly becoming the standard format for video and rightfully so, as it offers great video quality and small file sizes. It is supported by iPod with Video, AppleTV, PSP and many other devices, however compressing videos to this format is a time consuming endeavor. On my Mac Mini converting a recorded movie can take all night. Elgato has come up with a USB device called Elgato Turbo.264, which speeds up the process very much indeed, read the review for full details.