forbes:
According to the tech specs sheet they both do video upconversion but no video scaling (whatever the difference is beats me!
Video conversion is converting an incoming signal into something else for outputting (usually hdimi) i.e connecting a non compliant hdmi video device (old school dvd player) to the amp and the amp will take that signal and output it through hdmi.
Video scaling is the process of taking a lower resolution signal, scaling it and outputting a higher resolution signal (usually 720 or 1080)
Video scaling is not necessarily needed as most new equipment (dvd players, skyHD etc) are capable of outputting 1080p signals and as a last resort your HD tv will scale the signal to fit its resolution but the results differ depending on the said equipments ability to scale.
I would say video conversion is more important because you can add various types of non hd equipment to the amp and, in the 763 case, it will output these signals through hdmi (one cable) to the tv. However, the 763 does not scale any signal so if I feed it a 720 signal it will output a 720 signal.
Hope this helps......