It's always easier to see in slow-mo (thanks for that
@Longestday). In your last post, the first vid is midline and the second is triple with twirl motion (the motioning A-Back "twirls" and goes back the way he came).
OL-wise both look pretty similar: the backside guys scoop and the play side climbs to the second level, avoiding the DE and OLB.
The first vid is midline because:
1. the path of the motioning A-Back post-snap: he plants and cuts toward the LOS to get a block. If it were triple he'd continue his tail motion to be the pitch man.
2. More subtly, TQM's arms are out at a 90' angle during the mesh. Imagine for sec that when he gets the snap he's facing 12 o'clock. He rotates to face 3 o'clock and his arms are pointing straight out at 3 o'clock. In the second vid his arms are more towards 4 o'clock. It's super-subtle and you'd never see it at regular speed (unless you're CPJ) and the arm extension to 4 o'clock on the triple is for a longer ride-and-decide during the mesh whereas midline has to be super-quick.
3. Finally, the footwork is different. For midline the first step by his left foot is to get depth and his right foot comes back to keep from tripping the B-Back. On the triple he opens up to the play side with his right foot then brings his left foot parallel so they are both facing 3 o'clock. Well, he's supposed to, anyway, because you don't want to trip the B with your feet ... if you notice, his left foot sticks out further than his right, and that's the kind of stuff that would drive Johnson crazy, particularly if Mason or Howard tripped over it.
Fantastic play call by Johnson on 3rd and 5 and a fantastic read by TQM.