you can’t shrink them just like it was done back in DVD Shrink time.
one, check how many audio streams it has, drop PCM, DTS, or any of those new “HD” sound formats. Leave only AC3, if there is no AC3, convert one of the “HD” formats to AC3
Video, the only way possible is to re-encode the movie, if you want decent quality is very very very very long process.
I re-encoded two about hour and half movies from mpeg2 to mpeg4 on dual core AMD and it took over 40 hours to complete.
i used highest settings in nero vision with 2 pass VBR.