How Can I Reduce The Size Of Videos From My Video Camera But Will Not Reduce The Quality?

Whenever I upload videos from my video camera (mini-DV) a 1 hour video occupies so much space (around 24GB). I cannot burn that much in one DVD of which has only around 4.7GB capacity. How can I convert the video to something smaller without reducing the quality so that this 1 hour video can fit in 1 DVD.