Rebuilt ISO larger file size?

[retsam]

I tried to burn some ISOs but got that "Optimal L1 Data Zone Start LBA: None Found! (VTS_01) This image has not been mastered correctly for burning onto a double layer (OTP Track Path) disc. None of the cells meet the 'DVD-Video specification' criteria for a potential layer break position." error. So I extracted the files and rebuilt with ImgBurn selecting a layer break point.

 

But the resulting iso is much larger than the original. The original was 6.64gb and the ImgBurn rebuilt iso is 7.62gb. I know the rebuilt iso will also fit on a DL but I'm just wondering the reason why or if I did anything wrong.

 

Thanks for any info.

[LIGHTNING UK!]

It's to do with the amount of padding that was added due to the layer break you selected.