Converting 60p or 30p footage to smooth 24p: a quick guide

24 frames per second has long been the standard frame rate for film production.  30fps and 60fps have a distinctly “video” look, which is often undesirable.  So how do you achieve this cinematic look if your camera only shoots 60 or 30fps, and you don’t want everything to be slow motion?  It may seem as simple as dropping your footage into a 24p timeline, but that can result in choppy playback.  Here are some tips to help you achieve a smoother result.

Shooting

During production, if you are sure you don’t want to do slow motion, set your shutter speed manually to 1/50 or 1/40.  This will greatly smooth the footage when converting to 24p.

Post Production: Importing footage

Though Final Cut Pro, FCP X, Premiere, and Vegas use different interfaces, the principles remain the same.

  • Set up a project with a 24p timeline.
  • I’m assuming you’re shooting AVCHD, which is the standard format for most non-24p cameras.  In FCP 7, import using Log and Transfer.  In FCP X, use the Import tool when you connect the camera or card to the computer.  In Premiere, you choose the Private folder from your Media Browser, or find it via File > Import.
  • Transcode/proxy your footage as necessary.  You can either use your NLE’s native conversion tools, or you can use Mpeg Streamclip, Clipwrap, or Adobe Media Encoder.  Preserve the native frame rate – don’t try to convert to 24p yet.

Achieving Smooth 24p, 100% Speed (non-slow motion)

Here’s the problem with 60p and 30p: they don’t divide into 24 by any whole number.  60/24 = 2.5, so you’re dropping every third frame.  30/24 is 1.25 and creates the same issue.  This results in jerky playback.  For easily achieving smooth playback, I recommend FCP X.

rate conform

Rate Conform in FCP X for smoother playback

The key to smoothing the playback in FCP X is a tool called “Rate Conform” and is located in your Inspector in Video, below Spatial Conform.  You have four options here:

  • Floor: drops every third frame. Use on shots with little motion.
  • Nearest Neighbor: similar to Floor but is mathematically somehow different; it doesn’t really matter.  Just try it on shots that don’t quite look smooth with floor.
  • Frame Blending: blends nearby frames to create in-between frames.  Works well on shots with a moderate amount of motion.  Slow-moving subjects look better.  If someone is waving a hand, or walking across frame against a contrasting background, it will probably look bad.
  • Optical Flow: creates in-between frames by morphing.  Creates the smoothest results of the three.  Takes forever to render. Use on the toughest shots.

Note that your jerky motion could also be related to using the wrong shutter speed when shooting.

If you’re shooting a fast-moving subject at 1/60 or above, it might look fine at 60p, but atrocious at 24p.  To fix this, I recommend ReelSmart Motion Blur.  This plug-in adds back the motion blur missing in your footage to create a smoother overall look.  Just drag and drop the effect on the clip in your 24p timeline, and it will automatically fix the blur.  No tweaking necessary unless you notice too many warping artifacts.  Be aware that this will increase render time significantly.

If you don’t use FCP X:

For all other major NLE programs, you can still use ReelSmart Motion Blur.  You can also use the plugin Twixtor to create the same effect as Optical Flow – creating smooth in-between frames.   Click here for a tutorial on using Twixtor in Adobe After Effects.

Slow Motion

Achieving smooth slow-mo is much simpler, so I’ll only briefly touch on this.  Again, I recommend FCP X for the easiest and most flexible slow motion.

In FCP X:

  • Select your clip in the timeline
  • Modify > Retime > Conform Speed
  • Or select a clip in the timeline > hold Command + R > drag the top right  corner of the clip in the timeline.

In FCP 7: Follow this link for a video tutorial.

In Premiere Pro: Follow this link for a video tutorial.

In iMovie: Follow this link for a tutorial.  But don’t use iMovie.  Seriously.

Feel free to ask questions – I will happily update this article to include any missing info!

 

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    Latest Comments
    1. Mario

      I wish it this technique in Premier was that easy.
      Shooting everything in 60p gives you so much more posibilities in Post.
      I hope Adobe will copy this feature in a future Version.`

    2. JoseC

      Is there any way to convert the 60p from Sony RX100 to 24p and using Premiere Elements? I’m trying to avoid having to buy the new RX100 II simply to accomplish 24p that wasn’t available on the original.

      • Brandon Li

        I’ve never used Premiere Elements, only Premiere Pro. But in that program you can simply drop the footage into the timeline and it will be converted to 24p. Bear in mind that the footage might appear a bit jerky depending on the frame rate you used to shoot. 1/40 sec tends to look the best.

        The best way to go, however time consuming, is to use Twixtor to interpolate the frames. This is the same process they used on Act of Valor, which was shot 30p and then released as a motion picture at 24p.

    3. Nick

      I own the RX100 MK2 which offers a PAL/NTSC switch.

      When in PAL Mode you get 25p/50p options, in NTSC you can shoot in 24p/30p/60p.

      I want to render all my movies out to 24 fps. I also want to make use of slowmo now and again. Taking into account the fact that I’m in PAL land should I shoot in NTSC mode at 60 fps and slowmo down to 24p, or does 50p confirmed to 24p provide a better result?

      • Brandon Li

        You will get better 25p (PAL) results if you start out at 50p, so I’d suggest shooting at that framerate.

        • Nick

          Thanks! What about the shutter speed when shooting at 50p? Best to shoot at 1/100 or 1/50 if the end result will be in 24p?

          • Brandon Li

            If you’re looking to do slow motion, I’d recommend 1/100 or higher as your shutter speed. I find that slow mo tends to look good with no motion blur at all. If you’re aiming for regular motion, you should still stick to 1/50.

            • Nick

              Seeing as I don’t really want to switch between 25p and 50p shooting modes, I’ll stick to shooting at 50p 1/50 shutter (got the MagFilter + ND 8 stop on the way). In post I’ll slowdown the footage by 4% in a 24p timeline.

              Thanks for you help!

    4. Mark

      Just a couple things to add. I owned the RX100 for about 7 months and have lots of video to work with. With some effort you can achieve something “close” to an authentic 24p look and feel. I tried various methods with varying results, including the use of RSMB and resampling of frames.

      I use Sony Vegas, which if you drop 60i media into the timeline will give an unacceptable result if you use RSMB or even a stabilizer like Mercalli unless the render is the same framerate as the source. Deinterlacing, when done at the time of render with effects, screws things up when changing to 24p. The only workaround is perhaps to deinterlace and then transcode to an intermediate format at 24p first, and then edit and add effects. I guess FCP is better in that respect.

      I just picked up the RX100M2 mainly because I desired native 24p capability, and also for the reported marginal improvement in low light. I am not disappointed. The 24p footage is superior to any method I have tried to conform 60i. There is definitely a noticeable improvement in low light video as well. I was in a pitch black room with a faint red light, I could barely see anything with my own eyes – the video had trouble focusing at first, but I was surprised when I viewed it on my PC, it was actually acceptable. Given the lighting the graininess was very tolerable and with a little processing could be very good.

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