Scalping is still possible without understanding the tech - you could just stream a video of the bar codes and sell the stream instead of selling the ticket.
Recording the ticket with a video is everyone's first thought at defeating their restriction, and is no doubt the first thing they thought of when designing it. Hence, the codes expiring too quickly that you'll need a new video before you get through the line at the entrance of the venue. And messing with videos in a pressured line of people in front of a bouncer, is, as others have said, simply not practical for the vast majority of cases.
So it's kind of irrelevant - practically speaking - that it is possible.