How does premiere export 23.976 timeline to 24p output?

Hi lcagaiden,

If you export 24fps from a 23.976fps sequence, Premiere will repeat a frame at certain intervals because 23.976 is slower. It's hard to noticed because it doesn't happen every second, as it would if you exported 25fps from a 24fps sequence.

The only way to do this properly is to export your sequence in its native 23.976fps, then import that file into your project. In the project window, right click on your video go to Modify > Interpret Footage. A window will open that will allow you to set a frame rate manually for this clip. Choose "Assume this frame rate" and type in 24; click okay. The video will now play back at exactly 24fps. Create a new sequence that is exactly 24fps, name it accordingly, and drop your modified clip in it. You can now export this sequence to create a 24fps file that will not have repeated frames. When you export, the audio will be processed because you have changed the speed of the audio and it has to be resampled.

Cheers,

Hint: the drop-frame 29.97 fps timecode is exactly 1 hour, the non-drop is ~3.6 seconds longer in true duration.

The ONLY people who actually care about this accuracy are broadcasters because they all have to have the network affiliates on the same clock when jumping from network programing to local and back. If broadcasters used non-drop TC (where every single frame has a sequencial assending number) then all programming would be off by 3.6 seconds every hour. I deliver 30 second spots for broadcast several times a week and I use non-drop (don't tell anyone!) because the difference is undetectable in 30 seconds.

Well, now that could depend on how you're measuring the duration.

If you're using a video player or Premiere and simply checking the duration on the counter, it won't show a difference, you still have essentially 24 (23.976 or 24) frames per second and the ticker will turn over to 1 second after every 24 frames. If you could actually use (and trust) a stopwatch to measure the duration, you would see a 1/1000 difference in duration or about 5 seconds over a 1 hour 20 minute time span (if I have my math right?).

Now, you've opened a different can of worms that salvo34 eluded to with the difference between non-drop and drop frame time code. In the 29.97fps world, 1 hour of non-drop frame timecode is not the same duration as 1 hour of drop-frame time code but a video player or Premiere will call them both 1 hour.