I think you're talking about this stuff.
I'm not too familiar with ATI (er..AMD) cards to be honest. But I've never heard of a 9770. Googling shows the 9700 came out in 2002. I would assume it's a derivative of it. I don't know how much a card from 2002 could help with video encoding. Perhaps you have the model number of your video card wrong?
Modern cards can, however, assist with encoding. I use Nvidia cards and CUDA is quite handy for speeding up encoding. Though only with certain formats. I assume the AMD (ATI ATI ATI!!1) cards are similarly limited.