I hope this is in the right forum.

I was practicing a few things this morning to see if I could work out some problems (I'm a newbie to all this).

I demuxed a vob file using TMPGEnc Plus...ended up with a .m2v & .ac3 file. Good enough. I made NO editing to the files, and just multiplexed them back to the VOB file. When I did this, I got a file size this is different from the original. Why is this? And is it normal?

Details (using different tools for the muxing):

Original vob: 247,847 KB
mpeg-vcr: 247,839 KB
tmpgenc plus: 247,531 KB

I know it's barely anything, but I'm just curious. I figured the file should end up the same size as the original since I'm only breaking it down & rebuilding it.