3:2 pulldown is the process of going from 24 frames per second of film to 60 fields per second of interlaced video (30 video frames per second). This is usually what a Telecine does when transferring film to video. Pulldown can also be applied to convert between 24 frames per second and 50 fields per second of interlaced video (PAL). In this case, it is referred to as PAL pulldown or 2:2:2:2:2:2:2:2:2:2:2:3.
The 3:2 process works on chunks of 4 film frames to produce chunks of 5 video frames (10 fields); given film frames A, B, C, and D, it produces video frames AA, BB, BC, CD, DD (the first and second letter correspond to what goes in the first and second field respectively).
To recover the original 24 frames per second of film and perform compositing work on progressive frames, you need to go through the reverse process, called 3:2 pullup. In order to do this, you need to know:
The Pulldown tool will do both pulldown and pullup for 30 and 25 frames per second. The four possible operations are selected from the Conversion menu.
You can then select the pulldown cadence by choosing one of the following five patterns of whole (W) and split (S) frames from the Cadence menu.
Whole and Split frames are a consequence of using every second input frame to create three output fields and every other input frame to create two output fields, as in the following list of output field pairs.
