Question re create disc file size

singha · Post by **singha** » Mon Sep 11, 2006 9:25 pm

I have 2 clips extracted from DVD's, saved in library as .mpg files. When I was ready to burn to disc, I added the 2 clips in Edit mode, then proceeded to 'Create Disc'. At this point VS told me the end product will be over 5Gb. This was surprising as the 2 combined clips are only about 1hr 40min long.

Then I tried going into 'Create Disc' with no clips, and added the 2 clips in the 'Create Disc' screen. Now, VS told me the end product will be about 1.6Gb. ???

What are the differences in the 2 methods of creating discs? Why the huge discrepancies in file sizes? I actually went ahead and burned both into DVD folders and both files can be watched using a dvd viewer with no apparent differences. Would the 5Gb version give a better picture on a widescreen TV using a standard dvd player?

Thanks in advance for your info.
singha

DVDDoug · Post by **DVDDoug** » Mon Sep 11, 2006 11:10 pm

It's a matter of bitrate.

The bitrate is measured in kbps (kilobits per second) or mbps (megabits per second). That determines how many hours you can fit on a 4.7GB disc. (Megabits per second -> gigibytes per hour.)

Here's a handy Bitrate Calculator.

Higher bitrate = higher quality = more disc space = lower compression = less playing time.

Lower bitrate = lower quality = less disc space = higher compression = more playing time.[/b]

If you are copying clips from a DVD, it's best not to re-code the MPEG if possible. There is a check-box on the Project Properties screen that says Do Not Convert Compliant MPEG Files. Under ideal conditions, your DVD can have video quality that is digitally identical to the original DVD. That will only work if all of the clips in your project have the same bitrate (and other properties).