I asked DVDMF5 to join (4) four mpg files with a total size of 3.25 GB. I then chose EXPORT/Fast Export DVD compliant. Ulead went into labor and the bar at the bottom of the window shows that it is trying to compress 5.9 GB down to 4.7 GB. How could files that separately totaled 3.5 GB, joined be 5.9? There are not any added menus or such. Thanks for helping this ignorant newbie.
If the files were not DVD compliant then they would have to be encoded. Depending on the running time and the applied bitrate (size=running time x bitrate) the result may be a larger file.