From the video notes: “This is footage of Orbital ATK’s QM-2 solid rocket booster test taken by NASA’s High Dynamic Range Stereo X (HiDyRS-X) camera. HiDyRS-X records high speed, high dynamic range footage in multiple exposures simultaneously for use in analyzing rocket engine tests. Traditional high speed video cameras are limited to shooting in one exposure at a time, but HiDyRS-X can record multiple high speed video exposures at once, combining them into a high dynamic range video that adequately exposes all areas of the video image for comprehensive analysis.”
The video doesn’t change much over the three minutes, so if you watch a few seconds of it you can see how it works. As an aerospace engineer who was most interested in propulsion, watching the rocket plume is cool.