3 Replies Latest reply on Nov 24, 2009 12:55 AM by bullogger

    CS4 vs. Interpret footage (23,976)



      Windows 7 (64)

      Premiere CS4 (Demo)

      AJA Bord

      Uncompressed AVI (v210) workflow


      I used to work with CS2 and I may upgrade to CS4. In my tests I was not able to use interpret footage propperly.


      No matter what I tried, every source file (24, 25 and even 23,976) can not be interpreted as 23,976.


      Premiere always changes 23,976 to 23,98.


      1. This was working fine in CS2

      2. It seems like this is just a display problem and the files are still treaded correctly.


      Is there anyone who had the same problem?

        • 1. Re: CS4 vs. Interpret footage (23,976)
          Colin Brougham Level 6

          It's a display rounding issue, near as I can tell. Do this test:


          1. Import a clip that is 23.98fps. Take a note of the duration of the clip.
          2. Select "Interpret Footage" for that clip, and change the frame rate to "23.976".
          3. When you deselect the frame rate field, it will automatically round to two decimal places, e.g. 23.98. This will also be reflected in the project panel information area.
          4. Now take a note of the duration of the clip; it will be slightly longer. It IS now being interpreted as 23.976fps, hence the slightly longer duration.


          I found this to be the case with DVCPROHD 720p clips recorded using OnLocation; you can set OnLo to automatically remove the padded frames from a 720p/24p "over 60" stream to create true 24p AVIs. However, there's a bug in the way they're interpreted in Premiere Pro, in that they when they're imported, the pulldown is removed again, resulting in clips with 19.18fps. You can uncheck the "remove 24p pulldown" box in the interpret footage dialog, but they are then intepreted as 23.98fps. When trying to synchronize and multicam edit these files with 720/24pN clips recorded to a P2 card (which are correctly identified in Premiere as 23.976fps), they eventually go out of sync. So, in the interpret footage dialog, after unchecking the pulldown box, I have to manually enter "23.976"--again, it displays as "23.98", but the duration changes and the clips stay in perfect sync throughout the duration of the multicam.


          Hope that helps...

          • 2. Re: CS4 vs. Interpret footage (23,976)
            Jim_Simon Level 8

            I agree with Colin.  23.98 is just a shorthand display for 23.976.  There is no real difference.  (Sort of the way we say 30 fps, when 29.97 is closer to the reality.  But hell, even that's not entirely accurate.  It's just that saying or writing "1000/1001 frames per second" is a bit awkward.)

            • 3. Re: CS4 vs. Interpret footage (23,976)
              bullogger Level 1

              Bug or Feature


              2 files, both 23,976 (AJA v210 1920x1080) same lenght 00:24:00:00


              file 1 - no changes

              file 2 - interpret footage to 23,976 (after OK, changed to 23,98)


              tc's of file 2 change to:

              IN 01:24:00:00 to 01:28:06:16

              OUT 01:47:59:23 to 02:13:01:27!!!!!!

              DUR: 00:24:55:12


              When placed on the timeline both files have the same lentgh. So for the timeline both files are still 23,976, the TCs however are totally messed up.


              Obviously a dangerous bug wich should be fixed!