[Sociable]

As for software there are a number of free programs that will let you capture and manipulate the video so once you have sorted the capture/tv card and connections let me know what sort of things you want to do and I can steer you to free solutions that should cover most of what you want to do.

On the general point of quality the basic rule is work in uncompressed format until you have the finished video and then encode that to a suitable format depending on size and use constraints as the final stage. Note this will be space intensive though as video takes up a lot of space when it is uncompressed.

It is conversion to one of the compressed format that tends to be the major source of reductions in quality. (A bit like working with a copy of a copy of a copy) This is why I have suggested you work with uncompressed files if you have space.