Originally posted by: khamul02
I'm not sure how it is smaller when it is converted back to 30fps?

It is not really convert to 29,97 fps. You just enabled a flag in the mpeg stream that tells the player software to perform a 3:2 pulldown while playing.
This basically converts a group of 4 frames into a group of 5 frames. This happens 6 times per second. (24 fps divided into 6 groups per second == 4 frames per group, then create 5 frames out of these 4 in every group and still playback these 6 groups per seconds == equals 30 fps). The new frames are created by splitting frames into even and odd fields (think line numbers) and put together in a specific way.
Here is a more exact and technical description of this procedure:
http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm

You could just capture your LDs at 29,97 fps and encode it to mpeg with 29,97 fps interlaced mode, but 23,976 fps progressive mode usually gives much better results, so most people try to restore the original 24 fps from the laserdisc material by applying inverse telecine.

Greetings
Grisan