DVD file size with DVD Rebuilder

[travisbicks]

Until now I’ve been backing up my DVDs with DVD shrink but I’ve recently started to use DVD Rebuilder with QuEnc. I’ve done one backup and I’m happy with the results. I have some questions concerning the resultant file sizes however.

The main movie on the DVD I backed up was over 7 gig and I selected high quality (also trellis quantization) using QuEnc, so I was surprised to find that the files I produced were only 3.5 gig. My questions are:-

1) As the size of the encode is 3.5 gig, this means the full 4.7 gig capacity of the dvd I back up to is not being used. Am I therefore over compressing the files and would I obtain better results if I specified a higher bit rate manually in QuEnc, perhaps using a bit rate calculator to do this?
2) Is it possible to manually set the bitrate in QuEnc while using DVD Rebuilder or will Rebuilder over-ride any settings with standard settings?
3) If I can set the bit rate in QuEnc while using Rebuilder, should I set the bit rate and/or the max bit rate, or make use of the auto max bit rate function in QuEnc?
4) In order to use a bit rate calculator how can I determine what audio bit rate Rebuilder will use?

[Boulder]

What version of QuEnc did you use? One release had a problem with undersizing but the very latest one works fine (see the official thread in the MPEG1/2 encoders subforum).

[travisbicks]

Thanks,
I was using version QuEnc 0.70 and have now updated to version 0.70b. Before updating however I tried encoding the same DVD with trellis quantization disabled. The files size produced this time was 4gig and for some reason the picture quality was also improved. I believe the quality improvement may be due to the fact that during the first encode I was using a web browser on my computer.

Looking through the DVD Rebuilder forum section I have found that bitrate can be altered manually (though I’m not sure how), but that it is generally advised against by those in the know, including the author of the software.

[Boulder]

It doesn't matter whether you use your computer during encoding or not. You already have several processes running in the background even if you didn't do anything;)

[travisbicks]

Thanks, I was wondering whether using my computer made a difference or not :) I suppose the file size and lack of quality must have been the effect of using the trellis quantization then; I think I read somewhere in the MPEG-2 forum that it could be buggy.

[Boulder]

Using trellis with some quant matrices could produce artifacts. Anyway, I don't think using it is worth the extra time it needs.