Certain 59.94 clips play jittery on 23.98 timeline but play smoothly in the source window

Check the media data in MediaInfo ... download that free utility from their annoying page, then after install, simply drag/drop a file onto the desktop icon.

When MediaInfo then opens, go into the "Tree view", and you can see the actual file data. Posting a screengrab by drag/dropping it onto your text reply area would be good.

@Warren Heaton10841144  - thanks for the additonal details. Unfortuantely we don't have any details from the DP regarding the camera setup before we received this B-roll. I opened up the footage in Quicktime as well as Premiere and it simply displays the frame-rate as 59.94 with no indication if it's interlaced or progressive in the frame-rate field or properties (also tried VLC). 

@Stephen Barrante 

If the video is p59.94, there should be no duplicate frames.

If the video is i59.94 but originally 23.976 having gone through 3:2 pulldown, then there will be duplicate frames.  If i59.94 is viewed as single field, it may appear progressive when it's actually interlaced.

With digital cameras that record to tape, the 3:2 pulldown can happen in camera (hence the 3:2 pulldown removal option available during captrue from tape).  I don't think there's a tapeless camera that does 3:2 pulldown internally as it's not necessary.

Ideally, a DP shoots at the frame rate needed for the project for anything that's sync sound.  B-roll without sync sound can be shot at twice the frame rate or higher, but should always be a multiple of the sync sound frame rate.

This at times can happen with especially interlaced media going through framerate interpretations/changes. As actually, 59.94i and 29.97i are really the same thing ... interlaced media has two half-frames per "frame" if counted in 29.97 format.

So it can simply end up with a double frame showing here and there at times. Years ago, when interlaced was more common, this was a very widely handled issue. And most users probably had an idea off the bat what the problem was.

"We" don't all work with interlaced on a daily basis anymore, so it's a surprise.

Old post - but maybe this might help someone else experiencing a similiar issue. We discovereed based on this post - https://community.adobe.com/t5/premiere-pro-discussions/interpret-footage-from-60fps-to-24fps-results-in-choppy-weird-playback/m-p/14693774 that the footage we were provided, although encoded from camera at 59.94 fps, has in fact duplicated frames. Very easily spotted by hitting "next frame", and seeing every frame repeat. This explains why when we drop the frame rate down by 50% we do not get nice smooth "slo mo" b-roll, but a jittery mess. 

Alas we will have to use an AI tool like Topaz for select shots in order to produce our "slo-motion" frame rate on these troubled clips. While I want to blame the DP for not understanding this about the camera, I'm even more frustrated that this feature even exists. Maybe someone can explain, but it provides no value whatsoever except to simply double the file size. 

• Issue - stated at the top of this page
  
• Adobe Premiere Pro version number:  24.6.1 (build 2)
  
• Operating system - macOS sonoma 14.6.1
• System Info: CPU, GPU, RAM, HD:

  • CPU - not listed in mac studio system report.

  • GPU (Intel-based Macs and PCs)  not listed in mac studio system report.

  • GPU driver (PC) not listed in mac studio system report.

  • RAM not listed in mac studio system report but it says 128gb memory

  • Hard Drive (and, if external, how the drive is connected: USB 3, Thunderbolt, NAS, etc.). - 4tb ssd sandisk

• Video format: listed above in description paragraph at top of page
  
• Workflow details: played clips in source monitor then on timeline.
  
• Steps to reproduce - (Very important!) Described above in top paragraph
  
• Expected result - Described above in top paragraph, all 59.94 video should play normally on timeline
  
• Actual result -  some 59.94 plays choppey on timeline, some doesnt.
  

kevin can your team develop a script (no not a movie script) that will allow your team to collect all of that data with the push of a button by me?

All i-frame formats (also called intraframe formats) tend to be more forgiving when it comes to simply dropping a p59.94 or i59.94 clip into a p23.98 Timeline.

How does Optical Flow work on the problematic clips?

Ideally, if we have control over it, our Timeline frame rate matches our delivery frame rate, our source footage with sync sound matches your Timeline frame rate, and and our b-roll without sound can be at a higher frame rate that's a multiple of the Timeline frame rate (facilitating smooth slow motion as an option in post).

I disagree with your assessment. Half the 59.94 clips play fine in my timeline. The other half look jittery. It's inconsistent and doesn't make sense.

Timewarp in After Effects was formerly Khronos from the Foundry.  It's one of the top software-based options for exactly this issue before machine learning solutions become available. 

Your clips play well in the Source panel because the frame rate of the clip is being used.  These clips do not play well in the Program panel because a different frame rate is being used that is not a multiple of the source frame rate.