4 Replies Latest reply on Feb 26, 2010 6:38 AM by JoeDinosaur

    Frame rate issue

    JBrown321 Level 1

      Has anybody else had problems getting after effects to interpolate the frame rate acurately on import of a 24p file?   I have exported a quicktime and dv24 avi out of premiere in 23.987fps and when I import into After Effects it assumes it is 29.977fps. I have imported the file back into Premiere to double check that the files are 23.987 and it is.  Is this a bug?

        • 1. Re: Frame rate issue
          Todd_Kopriva Level 8

          23.987? That is a strange frame rate. The frame rate that is conventionally used for approximating 24fps from 29.97fps footage (using pulldown) is 23.976fps.

          • 2. Re: Frame rate issue
            JBrown321 Level 1

            23.976 you are right, my mistake, didn't get too much sleep last night.  But yes, the origional footage was shot at 24p, edited on a 24p timeline and rendered out at 24p and After Effects just does not read the file right.  I thought that it may be still be ok, but when I rendered out of AE at 24p the footage was slow on playback and out of sync. AE does really think the file is 29.97 for some odd reason?

            • 3. Re: Frame rate issue
              Adolfo Rozenfeld Adobe Employee

              It's not really a bug, but more like an omission.

              AE uses a text fille with information on how to interpret different footage types. The problem is that SD 23.976 progressive files are truly recorded as 29.97 with no real way to tell them apart except for a flag added by the editing application used to capture the content (assuming it's tape-based). AE can't see this flag automatically at this time for this kind of footage items.

              So, if you have (say) 30 such footage files in your project, this would be a  fast workaround:

              1. Select any of the 23.976 fps files, right click and go to Interpret Footage > Main (or press the new Interpret footage button in CS4, at the lower left corner of the project panel).

              2. In the remove pulldown menu, choose one of the 24P/24PA options (24P or 24PA depend on the camera and/or recording mode set in the camera).

              3. Still with the clip selected, right click and go to Interpret Footage > Remember Interpretation.

              4. Select all other 23.976 fps clips, right click and go to Interpret Footage > Apply interpretation.

               

              This way, you could correct the intrepretation for dozens of items in 30 seconds. It's still a workaround, of course.

              • 4. Re: Frame rate issue
                JoeDinosaur

                Hi Adolfo,

                 

                In my 3d application (Electric Image), I set the frame rate of a project to 23.976 fps and rendered it.  When I imported the rendered clip into After Effects and performed an "Interpret Footage" on it, After Effects said the frame rate of the clip was 23.98 fps.  In the Interpret Footage window I can replace 23.98 with 23.976.  Then, when I perform another Interpret Footage, it reports the frame rate as 23.976 fps.  Should I do this or leave the Interpret Footage value at 23.98?  Someone in a Premiere forum said this was just a rounding procedure for the display box (in Premiere).

                 

                Thank you in advance,

                 

                Joe T