Recommended Settings for Converting 60fps DOWN to 24fps?!

There seems to be no shortage of discussions and examples regarding the adding of frames (24 up to 60 for example), but I can’t seem to find any discussion regarding the removal of frames. Specifically, turning 60 fps footage into smooth 24 fps footage. Anyone have any experience with this or have any idea on recommended settings?

To add a little more detail… I need to deliver a finished video in 24 fps. I would just shoot everything in 24, except for this video requires some slow motion shots. And because most cameras (including MY camera) can’t shoot in 48 fps, the closest option I have is to shoot in 60 fps. This would allow me to play those slow mo shots at 40% in my 24 fps timeline. That’s great! Except, the shots that aren’t slow motion won’t convert cleanly down to 24 fps without dropping frames.

I figured I could just convert any non-slow motion shots in Topaz Video AI, but all of my test footage has visible glitches. I would’ve thought this software would be perfect for such a task, no?!

Agreed, it should be good at it, but I don’t think it was trained for that particular situation.
I know it’s kind of overkill, but what happens if you interpolated it to 120 FPS and then drop frames to 24 fps?
According to this Quora answer, interpolating to 120 FPS should give you the needed frame 2.5 and 7.5 to keep the motion smooth in 24 FPS.


That doesn’t work with VAI, as far as I can see.

To preserve all frames while changing the frame rate of a video, you just need to change the timestamps on each frame while re-encoding. With some video codecs, that’s even possible with a stream copy while remuxing, without re-encoding.

Assuming that you don’t need sound, with ffmpeg you can use something like this to create 24 fps slow motion from 60 fps video including all frames of the original:

ffmpeg -i “input” -an -r 24 -filter:v “setpts=60/24*PTS” -c:v prores -profile:v 2 “”

I’ve attached a clip in 720p60 with frame counter for you test the command line.

Jockey-FC (3.8 MB)

So here’s that clip using my method.
Jockey-FC (3.2 MB)
I think the motion turned out perfect. Just be sure to uncheck ‘Duplicate Frames Replace’ That messes the motion interpolation up.

I output to PNG and then use ffmpeg to encode back to video.
Here’s the exact command I used (Sadly you cannot use the TVAI ffmpeg to encode to H.265 like this command does, but that’s a tangent.):
"G:\Program Files (x86)\SVP 4\utils\ffmpeg.exe" -y -framerate 120 -i "E:\Dump\Jockey-FC 720p60_apo8\%%6d.png" -map 0:v -r 24 -c:v libx265 -crf 22 -pix_fmt yuv420p -preset slow -x265-params aq-mode=3 -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=0" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 "E:\Dump\Jockey-FC 720p60_apo8.mkv"

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Missed your post.

That looks to me as if you have created an image sequence beforehand and used it as input for the shown command line. I don’t see that this command line has anything to do with functions specific to Topaz VAI.

Would you mind explaining what it is supposed to show?

In TVAI, interpolate it to 120 fps with image output. Uncheck ‘Duplicate Frames Replace’.
That will create the image sequence. Then I supplied the ffmpeg command I used to get it back into movie format, but with the lower frame rate and smooth motion. The only important parts of that command are -framerate 120 and -r 24. That tells ffmpeg to drop frames to convert to the new frame rate.

You can, of course, do it with video files, but I’ll let you look up how best to do that. I use image sequences because I usually interpolate by 2.5X the original frame rate and then tell ffmpeg it was supposed to be 60 or 59.94fps all along.

Ah, ok. You used Topaz with frame interpolation to 120 fps to create the image sequence for ffmpeg. Got it.