2:3 Pulldown is a technique used to display video on an interlaced (60i) system that originates as 24 frames-per-second progressive. This is most familiar in the context of film-to-video transfers, but it’s becoming relevant in a new way. In this post I talked about some of the new external video recorders that are being made and many of them, like the Atomos Ninja, record whatever they’re given. Since they’re using signals from cameras that are meant to be sent to a monitor (via HDMI or SDI), they typically end up recording 60i video. So if you’re shooting 24p, 2:3 pulldown has been added and you’ll probably want to remove it to get the progressive video you intended. This post by Andy Shipsides at the Abel Cine Technica blog explains 2:3 pulldown in greater detail and shows two ways you can remove it.