The January patent filing adds to another patent filed in 2006 when the original Apple iPhone was being developed. Fast forward to current times and the Apple iPhone 5 still has the same letterbox problem despite the increase in screen size and in vertical resolution. While it would obviously be a boon for those who like to watch movies or videos on their Apple iPhone, with the new screen size on the Apple iPhone 5, users of the latter device could really use this on those many apps that haven't been re-sized to fit the new 4 inch screen.
source: USPTO via Engadget
Apple's patent covers a technique for filing in the gaps on letterboxed video playing on the Apple iPhone