4 Replies Latest reply on Oct 7, 2009 3:34 PM by Jim_Simon

    How can I create 50p footage from 50i in Premiere or After FX?

    Marcello Mazzilli


      I'm trying to create 50p footage from 50i. Not 25p! I want to create 50p footage through a process that it is used in 100 HZ LCD TV sets

      This is the idea. If you have 50i footage you can easily interpolate fields and get a 25p footage. Fine.

      But I would like not to do a simple interpolation.

      Let's say I have two 50i frames. I want to create a frame between the two made with the lower field of the first one and the upper field from the second one . This is the process used by 100 Hz LCD monitors that can actually invent non-existent frames by this method.

      But Premiere doesn't work this way.

      If you try to export a 50i footage to 50p what you get is 50p footage with identical frames at twos (1=2, 3=4, etc..)

      You can try a slightly different approach.

      You can slow down 50% the 50i footage (and then speed it up again). This forces Premiere to interpolate and create an extra frame but.. here is the problem.. Premiere "thinks in frames".. and interpolates a totally new interlaced frame. This frame, coming from interpolation, is actually a "fake" frame Comes from nowhere and so it has much less definition then the originals (the one before and the one afterwards). If then you render, speed up at 200% and watch the result what you see is a good frame, a blurred frame, a good frame, a blurred frame, etc..


      Does anybody know a method of getting out 50 real interlaced or progressive frames with this composition?


      INTERLACED  (100i):  1U1L 1L2U 2U2L 2L3U 3U3L

      PROGRESSIVE 50p): (1U1L) (1L2U) (2U2L) (2L3U) (3U3L)   .... That is exactly as interlaced but with the two fields interpolated


      Also please note that this method applied on an edited movie creates smooth transitions at cuts (a frame that has 1 field from the scene before and one form the scene after).