PVR crashes?

[tehswifthq]

I use my PVR to record xbox 360 gameplay, but i used the display settings on xbox as 480p and had to stretch my clips out which made them look squashed according to my friends, but when i changed my display setting to 720p and made it widescreen, my pvr keeps saying the input resolution is the old one which was 720 x 480 which it should be 1080 x 720, with the completely different input setting on, i get a black screen unable to record, i need help fast to sort this situation out