*1 trillion. The camera itself does not shoot 1 trillion fps, but they used multiple shots captured at different points in time. The camera only shoots on one plane, meaning the images are useless by themselves. They used mirrors to counteract this.
They set up staggered camera shots of the same pulse of light being shot and then wove all the footage together. Say you have a camera that shoots 60fps. Now make sure you press record at the precisely one tenth of a second intervals. So you shoot 60fps at .1, .2, .3, all the way through a second. Then from the 2nd second on once you weave those 10 60fps shots, it will be at 600fps if you shot everything at the precisely correct interval and woven together with care (use computer programming to make sure everything is accurate).