hey there ... sonic foundry (now owned by sony i believe?) has an excellent program, Vegas ... check that out it allows you to edit specific frames. you can find it at http://forums.xisto.com/no_longer_exists/
only problem is the price, it's about $600 ... but worth every penny ... you can download the trial version though, so you wouldn't have to actually buy it to test to see if it does exactly what you want ... trial would probalby just not allow you to save, etc
-- bigredrosen