For smooth slow motion in DaVinci Resolve on Mac, match the clip’s speed to your timeline frame rate first. A 120 fps clip plays at quarter speed in a 30 fps timeline using captured frames; use interpolation only when you need a different result.

This workflow is for a Mac editor turning high-frame-rate footage into a finished slow-motion shot. It uses the controls documented in Blackmagic Design’s September 2026 DaVinci Resolve 21.1 reference manual, with a brief Final Cut Pro equivalent. Start with one short clip so you can check timing and image quality before applying the settings more widely. DaVinci Resolve 21.1 Reference Manual

Calculate the speed that uses every captured frame

You need two numbers: the source clip’s playback frame rate and the timeline frame rate. For footage that has retained its original recording rate, calculate the speed percentage as timeline fps ÷ source fps × 100. This follows the frame-for-frame playback principle Apple documents for its Automatic Speed command: every source frame plays once at the project’s frame rate. Change clip speed in Final Cut Pro for Mac

Source frame rate Timeline frame rate Speed for frame-for-frame slow motion Resulting duration
60 fps 24 fps 40% 2.5 times the original
60 fps 30 fps 50% Twice the original
120 fps 24 fps 20% Five times the original
120 fps 30 fps 25% Four times the original
59.94 fps 29.97 fps 50% Twice the original

These are calculated examples, assuming constant-frame-rate footage with distinct captured frames and no previous speed adjustment. Use the actual rates reported for your media and timeline. Treat 59.94 and 60, or 29.97 and 30, as different numbers when calculating the ratio.

For an illustrative 10-second, 120 fps recording, there are 1,200 captured frames. Playing those frames once each at 30 fps takes 40 seconds. At 25% speed, the timeline therefore has a captured frame for every output frame. At 12.5% speed, the shot lasts 80 seconds: the same 1,200 frames must fill 2,400 output positions, so the editor must repeat frames or create intermediate images.

This calculation gives you a useful starting point, not a guarantee that every shot will look equally fluid. It tells you when the requested slowdown has enough captured frames to fill the timeline without synthesizing additional motion.

Set up Resolve without slowing the clip twice

Before importing footage into a new project, open Project Settings and choose your intended Timeline frame rate in Master Settings. For the worked example, use 30 fps. If Resolve asks whether to change the project to match the imported 120 fps footage, choose Don’t Change to retain the intended delivery rate. Blackmagic’s manual documents this import choice and warns that the project frame rate becomes fixed after media is imported. DaVinci Resolve 21.1 Reference Manual, “Adding and Organizing Media with the Media Pool”

Check how Resolve interprets the source before applying a percentage. A clip described as “shot at 120 fps” may already arrive with a slower playback interpretation. Inspect its frame-rate information and watch it at normal timeline speed. If it already shows the intended slow motion, applying another 25% adjustment would slow that existing result again.

Resolve also offers Video Frame Rate in the Video panel of Clip Attributes. Changing this interpretation changes the clip’s duration and relative video playback speed, while its audio remains unaffected. For this workflow, retain the correct source interpretation and make the creative speed change on the timeline. If you previously changed the interpretation, account for that change before using the table. DaVinci Resolve 21.1 Reference Manual, “Modifying Clips and Clip Attributes”

Apply a precise slow-motion speed in Resolve

Use a single clip on a simple timeline for the first pass. The following procedure uses the Inspector because Blackmagic documents its speed controls for both the Cut and Edit pages. DaVinci Resolve 21.1 Reference Manual, “Using the Inspector in the Cut Page”

  1. Place the clip on the timeline and select it.
  2. Open Inspector, choose the video controls, and expand Speed Change.
  3. Keep the forward playback direction selected.
  4. Enable Ripple Sequence if you want following clips to move to accommodate the longer shot. Check the surrounding edit before doing this in an assembled sequence.
  5. Enter the calculated value in Speed %. For an unchanged 120 fps source in a 30 fps timeline, enter 25%.
  6. Check the new duration and confirm that the shot still includes the intended beginning and ending.

The Inspector also provides Frames Per Second and Duration controls. Entering a duration makes Resolve calculate a speed that fits the clip’s frames into that time. For a predictable first result, use the calculated percentage before adjusting the shot to a different editorial duration. DaVinci Resolve 21.1 Reference Manual, “Using the Inspector in the Cut Page”

Next, expand Retime and Scaling and explicitly select Nearest for Retime Process. This provides a baseline without motion-generated intermediate frames. The clip-level setting overrides the inherited Project Settings choice, which matters if the project already uses optical flow. Resolve documents Nearest, Frame Blend, and Optical Flow as its three retime-processing choices. DaVinci Resolve 21.1 Reference Manual, “Retime and Scaling” and “Frame Interpolation”

At the exact frame-for-frame ratio, first judge whether the captured motion already gives you the result you want. Keep that version as your comparison before trying a slower percentage or another processing method.

Choose interpolation only when the shot needs it

If the calculated speed is still too fast for your edit, reduce Speed % further and compare the available retime methods. Blackmagic documents that Nearest repeats or drops frames, while Frame Blend blends adjacent frames. The manual also notes that frame blending can be preferable when optical flow produces unwanted artifacts. DaVinci Resolve 21.1 Reference Manual, “Frame Interpolation”

Method What to assess in your comparison
Nearest Whether repeated frames create visible pauses in movement
Frame Blend Whether smoother movement comes with distracting doubled edges
Optical Flow Whether generated motion preserves object shapes and boundaries
Studio’s Speed Warp processing Whether the additional processing improves this particular shot

To test optical flow, select the timeline clip, open Inspector, expand Retime and Scaling, and change Retime Process to Optical Flow. Then compare the available choices under Motion Estimation. Blackmagic explicitly cautions that different methods produce different artifacts and that the highest-quality setting is not always the best choice for a particular clip. DaVinci Resolve 21.1 Reference Manual, “Retime and Scaling”

Speed Warp is a DaVinci Resolve Studio feature. Blackmagic’s current Studio documentation places this retiming technology among its exclusive Neural Engine tools. In the free edition, use the captured-frame ratio or compare the standard retime methods instead. DaVinci Resolve Studio

For a neutral comparison shot, use footage of a patterned disc rotating past a stationary rectangular card. Inspect the disc’s markings, the card’s straight edge, and the point where one object passes behind the other. This is a suggested diagnostic subject, not a reported test result. Reject a processing choice if it makes those shapes visibly stretch, split, or pulse, even when the overall motion initially looks smoother.

Separate preview performance from retiming artifacts

A demanding effect can make timeline playback uneven even when its rendered frames are usable. Resolve’s manual recommends the render cache for processor-intensive media and effects when real-time playback is unavailable. Before changing your speed again, let the effect cache or export a short test. DaVinci Resolve 21.1 Reference Manual, “Improving Performance, Proxies, and the Render Cache”

Choose Playback → Render Cache → Smart and allow caching to finish for the test section. Resolve’s timeline cache indicators use red for material awaiting caching and blue for material already cached. Background caching can begin during inactivity when enabled in the project settings. DaVinci Resolve 21.1 Reference Manual, “Using the Smart or User Cache Improves Effects Performance”

Use this diagnostic sequence:

  1. Play the cached section continuously to judge the rhythm of movement.
  2. Step through the same section frame by frame to inspect object boundaries.
  3. Export a short sample at the intended timeline frame rate and inspect it separately.
  4. If only the live preview hesitates, investigate playback performance. If the exported images contain repeated pauses, blended outlines, or distorted shapes, revisit the speed and retime method.

For a normal finished movie, use Single Clip output on the Deliver page and verify the intended output frame rate. Blackmagic distinguishes this from Individual Source Clips: single-clip output converts the timeline’s clips to the timeline frame rate, while individual-source rendering preserves source-rate behavior. DaVinci Resolve 21.1 Reference Manual, “Importing and Conforming Timelines”

Handle audio and the Final Cut Pro equivalent

When retaining attached audio, review Pitch Correction in Resolve’s Speed Change controls. It changes audio duration with the picture while correcting pitch. Blackmagic cautions that large speed adjustments may sound less natural than small ones. Listen to the processed result rather than assuming the checkbox will make extreme stretching suitable. DaVinci Resolve 21.1 Reference Manual, “Using the Inspector in the Cut Page”

For a purely visual shot, an editorial alternative is to omit the recorded clip audio and place a separate soundtrack beneath the finished slow-motion sequence. That lets you choose picture timing without requiring a heavily stretched recording to carry the scene.

If you already edit in Final Cut Pro, select the high-frame-rate timeline clip and choose Automatic Speed from the Retime pop-up menu below the viewer. Apple documents that this plays every source frame once at the project rate. For further slowdown, its Smooth Slo-Mo feature requires Apple silicon; frame sizes above 4K require M2 or later, and the maximum is 8K. Other documented options include frame blending and optical flow. Change clip speed in Final Cut Pro for Mac

Finish by checking three things together: the slowdown fits the edit, moving shapes remain consistent, and the exported file plays as intended. The frame-rate calculation gives you a dependable starting point; a cached comparison and a short export help you choose how far beyond it the particular shot can go.

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