The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
The application Video Quality its designed to let you choose between the three video resolution modes of the iPhone/iPod (for devices with camera). You can choose, record and save the video in any of the three resolutions available: low resolution, medium resolution (device default) and high resolution.