In the video a pattern of smoke ejections along the east face of WTC 1 just as the airplane hits WTC 2 can be seen. A small fireball ejection from the fl 98 NW corner is also seen. NIST addresses this point in their reports and attributes the east face smoke ejections to an underpressure wave created by the airplane impact.
If you look at the clip carefully you can see that the initial smoke ejections along the east face happen when the surrounding air is still. A type of shock wave is a possibility, though by observing the smoke we can see that the initial ejections in question happen before the pressure wave affects the surrounding smoke along the facade. You can then see the effects of the pressure wave hitting the facade moments later, followed by an underpressure wave, by the way the smoke moves.
Smoke release points along the east face:
FIre and smoke ejections from 2 points along the northwest corner, floor 98: