Most HT buffs have at least heard of 3:2-pulldown detection. Film is projected at 24 frames per second, while NTSC television is displayed at 30 frames per second. Why? Because the alternating current that comes out of our wall outlets cycles at 60 hertz. Sixty interlaced fields of video per second sync up nicely with 60 cycles of electricity in the same time period. Your eyes combine 60 fields into 30 frames. (Actually, NTSC video is displayed at 29.97 frames per second, but don't ask and, really, don't even think about it.)

In order to show 24-fps film on 30-fps TV, you either have to speed the film up (not a good idea for us, although Europe does this because their TV system operates at 25 fps) or duplicate fields in the process of converting the film to video, a process called telecine. If you record one frame of film as three video fields (duplicating one of the actual fields), the next frame of film as two fields, the next frame as three fields, and so on, you end up with 30 frames at the end of each second. This process is called 3:2 pulldown.

When telecined film material on a DVD is sent to a DVD player's interlaced output, each video frame consists of two fields that are sent one after the other. However, in two out of every five video frames, the fields are derived from different film frames. Fortunately, this is not very noticeable on an interlaced display.

From the player's progressive output, the video frames also consist of two fields each, but they are sent in a single pass and repeated in an alternating pattern of three frames, then two frames, then three, etc. This can make motion (especially slow camera pans) appear slightly jerky.

Pioneer has taken the next step and done something so simple, it's worth your time to read this entire sidebar. Instead of trying zto make the 3:2 sequence appear less jerky, they did away with it altogether. The technique, called Advanced PureCinema, increases the display's refresh rate to 72 Hz (from 60). This allows them to show every film frame three times and removes any semblance of jerkiness. All TVs can technically do this (computer monitors have been doing it for years), but Pioneer gets credit for actually doing it in a home theater product.