24P vs 23.98P

Although the numbers are similar, the difference between them adds up quickly. I think it's easiest to think of 24 as "film speed" and 23.98 as "video speed." Today we are seeing almost all of the new solid state cameras shooting in 23.98 frames/second, which translates easily to 59.94 via 3:2 pulldown. 59.94 is the broadcast television frequency whether it be 1080i, 720p or 480i. In the case of using these cameras, you would set up your Avid/FCP project as 23.98 fps and you are off the the races. Examples would be Panasonic P2, XDCAM HD, RED cinema, etc.

When FILM is shot and transferred it's typically done so at 24.00 frames / second. In order to get the film into an Avid or NLE it typically comes from a telecined tape. Film is often run as a "one-light" or unsupervised transfer to a Digital Betacam or HDCAM. Once this happens, everything is in the video world and the film is now playing back at 23.98 fps.

Since we shot in film speed (24), will be finishing in film (24) and recorded all of our sound in film speed, it's important to edit in 24fps. The Avid does a great job here by digitizing the telecined tape, ingesting the 23.98 fps material, then playing it back at 24fps in the timeline. Now everything lines up correctly, the lists are correct, etc.

When you working in a 24fps project, the Avid gives you a few ways of looking at timecode. You can either have "regular" TC30 (... :27,28,29,00) or you can have TC24 (... :21,22,23,00) - this can be selected above the master timeline window.


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The logical question is "how can you have TC30 in a 24 frame timeline?" The answer is the Avid removes numbers from the timecode so that all the seconds will line up. For example 1:00:10:00 will be the same in both timecodes, but between the seconds things might not line up in terms of timecode. For example 1:00:21:11 in TC24 = 1:00:21:14 in TC30. Remember that timecode is simply a bookkeeping device and does not change timing. To make things easy down the road be sure to refer to everything in TC24 - both in terms of your master timeline and your source timecodes.

To make things slightly confusing, in the digital cut tool you have the option of playing the timeline back at 24 fps or 23.98 fps. If you are digital cutting back to tape, select 23.98 and all the timecodes on the tape (video world) will line up with your timecodes in your 24P timeline. Don't worry though, it will slow down the video and audio together to maintain sync but will NOT effect your 24 fps cut lists.