An enormous amount of manpower goes into the one minute (or so) highlight that play after a player is announced at the podium.
Here's what I'm talking about.
Today ESPN released a peek at the amount of work that goes into creating that highlight. Keep in mind that this isn't for just the first and second day NFL draftees, They've got film cut up from #1 overall to Mr. Irrelevant, and I'd guess all the guys that were projected to go in the late rounds that end up signing with teams as free agents.