2 Replies Latest reply on Mar 29, 2017 12:37 AM by A.I.1

    Ae 23.976 to 24 footage conversion for DCP

    GrizzlyAK Level 1

      I've look at other discussions on this topic, and still don't get what I'm seeing in my experiment. I have a Pr CS6 sequence that I opened in Ae CS6 through Dynamic Link (within Ae). The manual (and other advice) states that the best way to convert 23.976 footage to 24 in Ae is to conform it, using Interpret Footage in the Project Panel. It also says that it is a frame-per-frame conversion, that is, no frames are created or skipped, but that the new comp (at 24 fps), just plays back faster.

       

      OK, I get all that, and therefore would have expected to come out with a 24 fps comp that had the same number of frames, but whose Timecode was shorter than the original. In other words, the calculation Ae does for the TC / time ruler display is different for the two comps (23.976 and 24), but the number of frames and the actual frame sequence is identical.

       

      I did the following experiment.

      (1) Imported the 23.976 Pr Sequence into Ae project panel

      (2) Did it a second time and on that second footage item, reinterpreted it to be 24 fps.

      (3) Dragged the footage from (1) to the New Comp icon creating a 23.976 comp with the original footage

      (4) Dragged the footage from (2) to the New Comp icon creating a 24 comp with the reinterpreted footage.

       

      I found the following:

       

      What I looked at23.976 comp24 fps comp
      My 2 pop frame4848
      2 pop TC2:002:00
      A Particular Frame (image)Frame 1000Frame 1000
      LFOA1246912469
      LFOA TC8:39:138:39:13

       

      So, the footage in the two comps are identical, as expected, frame for frame, verifying that the correct frame rate is indicated in the TC in each. But, my calculations show that 12469 frames at 23.976 results in 520.0617284 sec, whereas 12469 frames at 24 fps results in 519.5416667, for a difference of 0.5200617 sec, or about 13 frames. Why is the TC in the 3rd column not 8:39:00 since the same frames played at 24 should run shorter than the original played at 23.976, as per the manual and everything I've read?

        • 1. Re: Ae 23.976 to 24 footage conversion for DCP
          GrizzlyAK Level 1

          In addition, I tried a couple of other methods that I thought would give different results, and they did. I did the following:

           

          (1) Created a new blank comp at 24 fps and dragged in the original 23.976 footage item from above.

          (2) Dragged the original 23.976 footage item to the New Comp icon and then changed the frame rate in the Comp Settings to 24 fps.

           

          Both of these methods gave identical results, and in the table below compare it to the 23.976/24 data shown previously.

           

          What I looked atPrevious 23.976 / 24 comp24 fps Comp created as shown above
          My 2 pop frame4849
          2 pop TC2:00

          2:01

          A Particular Frame (image)614 (FFOA)615 (FFOA)
          A Particular Frame (image)9991000
          A Particular Frame (image)9991001
          A Particular Frame (image)10001002
          A Particular Frame (image)80008009
          LFOA12469

          12482 (again, there's my 13 extra frames)

          LFOA TC8:39:138:40:02

           

          I'm not sure what Ae is doing here, but I suspect it is resampling, given that at about 1000, the new method creates a situation where a single frame is duplicated. This happens about every 1000 frames, consistent with the 0.1% time speedup from 23.976 to 24. Note that I do not have frame blend on, so it seems to be sticking to actual frames, just duplicating them as needed to keep things ... whatever.

           

          This is, I think, definitely NOT what I want to do to get from 23.976 to 24. The original posts seems to be the right way, but I don't understand why it is the same length. I do know that I need to compress my audio track to match. Any insight would be greatly appreciated.

          • 2. Re: Ae 23.976 to 24 footage conversion for DCP
            A.I.1 Level 3

            I had a try with the 1st method and got the results you got (not the same durations). It seems like it could be a bug to me (or at least not really working as should be expected). I also checked in "Project Settings" and set it to "start at 0" for frame count, and still didn't get the expected result.