No, in the video it is the core remains. For the perimeter they are way too massive, having the column distance mount provingly at least 3 times wider than was in case of perimeter structure (the column distance in chunks, compared to the north face 64m reference, is at least 4 meters, while the distance of the perimeter columns was 1m). Without any doubt what shows the video aren't the chunks of the perimeter.
The chunks of the core, in comparison with the north face size reference, were at least so wide as 6 floors of the North tower (technical floors weren't 6 floors!) and weighted at least several hundreds of tons. No way they would travel so far outside the perimeter in case of a gravitational collapse.
Also the clearly visible squibs during the North tower collapse prove the WTC7 was brought down by the controlled demolition as well.
The chunks are already far from the perimeter limit in the height about ~300 meters! - so it looks like they even were originaly ejected horizontaly or even a bit upwards/outwards. You say that the chunks are the remains of the technical floors, but the 2nd technical floors were in the height ~290 meters (so then the chunks must be ejected upwards/outwards - impossible in a gravitational collapse anyways) and anyway the floor truss even there was much much less massive than what shows the video.
The distance of the beams on the video looks like literally fitting in the proportions of the core mount. Also there were no other so massive structures in the building than the core. So I think it is good assumption the chunks are pieces of the core. (what shows your picture it is the perimeter remains, but what shows the video it is mostly definitely chunks of the core.)

What force ejected them?
I think a good asumption is - that it were literally loads of explosives.
That's maybe why the NIST doesn't want to study the "collapse", because they might come to the very same conclusions.
The video, IMHO is also an ultimate orbituary to the "pancake colapse" hypothesis.
Poll thread to the video also here:
http://z9.invisionfree.com/Pilots_For_Trut...opic=10291&st=0