Each time you render a video file it's going to be a bit lower quality than what you started with. If you want best quality (DV-AVI), it's gong to be a big file size. If you want smaller file size (WMV, or equivalent), it's going to be lower quality. If the video is to be put on DVD, save it as mpeg2. I find this to be the best with both file size and video quality also, but you need a player to play it if it's not going to be put on DVD. Download VLC player for that. Just play around with the settings rendering a test video that's about 10 seconds long just to see what settings you like.