Still wondering why Amazon Unbox doesn't offer any high-definition movie rentals? Yeah, me too. I like the convenience of renting movies on TiVo using Amazon's rental service, but the lack of new movies the service has to offer is problematic, not to mention the lack of HD content.

In TV Week, Jim Denney, TiVo's VP of product marketing, said that at the moment Unbox can't process HD content, but that will soon change "in the not too distant future." Apparently the companies plan to announce HD content as soon as cable companies figure out how to deal with bandwidth constraints.

This is good news considering how many people now own both TiVos and HDTVs.

Consumers with an Xbox 360, Vudu or Apple TV already have access to high-definition movie rentals, so Amazon has a lot of catching up to do. If you're wondering how all these services compare, check out Apple Insider's HD movie rental comparison chart here, and please feel free to tell us which one you like best.

Related:

Millions now own an HDTV, HD content not the main reason
A few more things you should know about the DTV transition
TV set-top battle: Apple TV vs Vudu