Depends on how compressible the DVD is, you are never going to get the same quality though since XviD is a lossy codec. To be a fair test you should start of with the pre DVD source that the studio used to create the DVD. Convert that to DVD quality and compare the size of the XviD encode vs. the DVD's MPEG2.
Like I said it depends on the movie. The avarge quant at that size could be quite different for 2 movies. If you were to encode at quant 2 and at full DVD res then it would be 99% quality. If a movie is quite long though and not very compressable then you would need to lower the resolution or you might have a very high average quant at that size.
The quant matrix used will also have a big impact. Take the same quant to encode and encode with h.263 and MPEG quants. The size of the MPEG one should be much larger. CQM's can have even more impact.
Basically there is no easy answer, you will just have to compress and see what you think.
A 1.36gb rip on a 90 minute movie should look excellent. I have done 2 hour movies into 1.36gb (using AutoGk, which im assuming you are using) and they have looked fine. As celtic_d said, it wont look like DVD, but its pretty damn good ;)
Thanks guys! It was a little too advanced for me Celtic_d, I'm not the biggest codec tech'ie, but I think I get your point ;)
DVDback23 just what I needed, I was wondering if the quality would improve if I encoded to 1400 Megs instead of 700 or if the quality pretty much remained the same.
Started to think that the quality of my 700 Megs XviD files seemed to look a bit lacky.
When I encode, I use Nic's XviDcodec. But my own conversions doesn't look as well as if I Download a XviD film. How come?!
Wondered if I should move over to the DivX 5 or 6 codecs instead?
yeah you should deffinatley at least try the DivX 6.0 codec. i use it and it's great especially if you set it to 'high definition profile' and set the quality level to 'insane', though it's very slow this way and you will need a fast pc with lots of ram or a lot of patience or ideally both!