Three hours and five minutes is a [B]very[/B] long movie to put into a DVD-5. I’m assuming you were making a dvd-video to fit onto a single layer dvd. So the bitrate is fairly low, and quality will suffer.
Anything at two and a half hours or over, you should encode to DVD-9. And three hours is max.
Were you using HCenc in a two pass encode? Or ffmpeg?