Michael,

As best I can... Film is made up of typically some twenty-five or thirty frames per second of play time and old celluloid film had an obvious string of individual images which you would cut between to do your editing. Though modern digital film is displayed as discrete 'frames', the information that is stored in the .MPG etc file is compressed and generally not. The de-compression for display may require information from several locations which takes time and computer power. To make the editing smoother MEP can create a table of complete frames once rather than doing the calculations every time a frame is displayed.

Because the creation of the frame table can take some time MEP gives you the option of doing the job as you load your clips, or a a convenient time later (while you have a coffee?), or not al all if you have a really powerful machine.

Hope this helps,

Carl