What format is the audio in ?. If its PCM WAV then no, but if its AC3 or MP2 then its poss to recompress it at a higher bitrate, prob not worth the effort and I bet you'd end up with sync probs. Best bet would be to run your finished 'DVD' through DVDshrink or DVD2one to compress it dopwn a lil bit to under 4.7gig