VBR, unable to fill CD

[vulcan4d]

Many times I downloaded SVCD's. They were in VBR format, and very close to 800mb file size. By close I mean by 2mb, more or less. Anyway I've been trying to convert my own SVCD's lately in VBR format and I NEVER am able to fill a CD. Using CBR it's easy, however when using VBR I get file sizes of 720-745mb. The whole point of vbr is to improve quality, I don't want wasted space on my cd. Anyway I know that vbr, variable, is difficult to calculate to fill the CD so I use tmpgenc to do it automaticly, however since I am not getting the same results can someone please tell me why? How can I fill a CD with VBR? The SVCD's I downloaded before were perfectly full and encoded in VBR.

[adam]

If you are using any form of 1-pass VBR then you can never completely predict the resulting file size. You have to do at least 2 passes to do the calculation.

Perhaps TMPGenc's internal bitrate calculator is not the best. If you look in the tools section there is a java one that works well enough, or you can try FitCD which will allow you to account for all the overhead that will go into your final SVCD. Simply do multipass VBR with the average bitrate that these programs calculate and you should have no problem coming within 1MB of your target size.

[Marty2003]

It's also possible your movie doesn't have a lot of motion, so with 2 pass vbr it's possible many of the scenes are close to your minimum bitrate and not a lot of scenes need the maximum. When I used to make svcd's most of them would be ~800 but others just wouldn't need the bitrate and were smaller.