Learn to Create Stunning Slow Motion in DaVinci Resolve 17

Slow motion is that awesome effect you see in so many movies and videos where time seems to stand still allowing you to see every detail of the action that is happening. We’ll show you how to create slow motion in DaVinci Resolve 17.

The super-smooth slow motion that you see in movies is filmed at high frame rates from 60 to 240 frames per second (fps) and above, then played at a lower frame rate like 24 frames per second to slow it down in real-time. One second of 240 fps footage takes 10 seconds to play at 24 frames per second giving you very smooth slow motion. Changing the speed at which the footage is played overtime is called speed ramping.

Part 1: Main Methods to Create Slow Motion in DaVinci Resolve 17

It is important to understand that to be able to slow down any footage you need to play it back at a lower frame rate than it was filmed. If it was not filmed at a higher frame rate you can’t slow it down without needing to create new frames to fill in the gaps.  While it is possible to do this, as we will see later, the best results are achieved using high frame rate footage and then slowing it down.

Let’s begin by creating a slow motion effect. In order for this to work well, the footage needs to be filmed in a frame rate of at least 2x the frame rate of your timeline e.g. with a 24 fps timeline the footage would need to have been filmed in at least 48 fps. Common frame rates for slow motion are 60, 120, and 240 fps. The higher the frame rate the more you can slow it down.  

Changing Clip Speed

The quickest way to slow down your footage is simply to change the clip speed. There are a few main ways to slow down footage in DaVinci Resolve 17.

Add some of your own high frame rate footage to the timeline in the Edit Page, or use some stock footage from Motion Array. Select the clip and check the frame rate in the metadata tab then check your timeline frame rate in the settings tab.  Use these two figures to work out how much you will be able to slow it down without losing frames then use one of the methods below to slow it down.

1. Press R to bring up the Change Speed dialogue. You can also access Change Clip Speed by right-clicking on the clip, or from the clip menu at the top of the interface. 
2. Change the speed to e.g. 50% to slow it down to half speed. Check the Ripple Timeline box and click Change. The clip now plays in 50% slow motion and has doubled in length. A speedometer icon appears on the clip, letting you know you have changed the speed of the clip. If you don’t check the ripple sequence box, the clip is played in slow motion for the duration of the original clip.
3. Press Ctrl+R or Cmd+R to bring up the re-time controls. You will see a dropdown menu with a %. Change this % to slow down the clip or select the edge of the clip and wait until you see double arrows appear. 
4. Now drag the edge of the clip to speed it out to slow it down. We will go into more detail about this method in Part 2.
5. In the media pool, you can right-click the clip and select Clip Attributes, then change the speed to match the timeline frame rate. This changes the playback frame rate of the clip so when you drop it onto the timeline the clip will play in slow motion to match the timeline frame rate. This is handy when you have a lot of b-roll that you want to play in slow motion without the need to retime it. It really speeds up editing.

Frame Interpolation Methods

When you don’t have enough frames to slow down your clip, DaVinci Resolve needs to use the frames it has to make up the missing frames, called frame interpolation. As an example, if you were to try and slow down a one-second-long 24 fps clip in a 24 fps timeline by 50%, DaVinci Resolve needs to create 24 new frames to fill in the gaps. 

Likewise, if you drop a 24 fps clip in a 30 fps timeline Resolve needs to create 6 more frames for every second of the clip. The frame interpolation method used has a big impact on the quality of the results. There are a few ways Resolve can do this.

1. Nearest is the least computer-intensive will generally play in real-time. This method displays the nearest frame to what needs to be shown. In the 24 fps example above, it would effectively double each frame by showing it twice.  The result would look very choppy.
2. Frame Blend does just that. It blends the frames on either side to create new frames in between. It is a bit more intensive on your computer but will deliver a better result and works reasonably well for timelapse footage. 
3. Optical Flow is a step up on frame blend, very intensive on your computer but will in most cases deliver superior results.
4. Speed Warp takes optical flow even further by using the DaVinci Resolve neural engine and machine learning to create the new frames. It delivers great results but is only available in the studio (paid) version of DaVinci Resolve and is very resource-intensive.

The frame interpolation method DaVinci uses is set in the project settings under Master Settings > Frame Interpolation or at the clip level in the Inspector under Retiming and Scaling.

Along with the Frame Interpolation options, you can set the Motion Estimation mode and Motion range for performance or quality (Faster vs Enhanced and Large to Small).

Audio and Slow Motion

Changing the speed a clip plays back in the timeline also affects the audio that is linked to that clip. This does not apply to changes made under clip attributes in the media pool or unlinked audio. To change separately recorded audio along with the clip you need to link the clip and the audio. 

Generally, audio for slow-motion clips should be dealt with separately (by unlinking it from the clip) unless you want the sound to change along with the clip. This may work in some instances where it is intended e.g. a slow-motion reaction shot. To achieve that slow-motion sound, untick the Pitch Correction box in the change clip speed dialog.

Part 2: Learn Speed Ramping in DaVinci Resolve 17

Speed ramping refers to changing the clip speed over time by adding speed points to the clip. The speed points allow you to break the clip into different sections that play at different speeds for great effect.

Retime Controls

1. To access the re-time controls press Ctrl+R or Cmd+R or right-click on the clip to bring up the Retime Controls. You can also access Retime Controls from the clip menu.
2. To add a default speed ramp click on the Speed drop-down and choose one of the ramp options. 
3. The clip will be broken into 5 speed points up from 0% or down to 0%. You can change the speed of each section as needed.
4. To add speed points manually move the playhead to where you want to add it, select the speed drop-down and click Add Speed Point. Add as many as you need and change each section to the speed you want it to play. The yellow arrows that appear on the clip indicate sections where the clip has been slowed down. 

Note: To hide the Retime Controls once you have made your changes, click the X beside Speed Change, or Cmd+R or Ctrl+R. 

5. You also have a variety of speed change options, as well as freeze frames and reverse speed. Freeze frames are red bars, rewind is reverse arrows, and if you speed up a clip above 100% you get closely spaced blue arrows.

Retime Curves

When adding speed points the changes between these points are abrupt. The retime curve in DaVinci Resolve 17 is used to smooth out the transition between speed points.

1. Right-click on the clip and select Retime Curves. Then select Retime Speed from the small dropdown on the top left. It defaults to Retime Frame.
2. You will see there are hard changes between the speed points.
3. To fix this, click on a speed point and select the bezier handles icon. You can now drag on the handles to smooth the speed change.
4. You can also click on the keyframe icon to add a new speed point then simply drag it up or down to change the speed of that section to change the speed.

Part 3: Troubleshooting Slow Motion Edits

There are a few main issues that you will come across when working with slow motion in DaVinci Resolve. The majority are caused by not understanding how DaVinci Resolve works with slow motion, which hopefully after reading the article you understand now. Below are some troubleshooting tips.

Choppy or Odd-looking Slow Motion

The simple answer here is that in most cases the footage has been slowed down beyond the available frames and DaVinci Resolve is making up new frames to compensate. There is no warning for this, you need to know the frame rates of your footage and how much you can push it. So check the frame rate and adjust your clip speed accordingly.

Alternatively, if you don’t have enough frames and still need to slow it down, play with the frame interpolation settings for the clip until you find a usable result. We advise caution here as these methods are resource-intensive and can bring even the most capable systems to a halt. You will most likely need time to let it render for smooth playback. This leads us to the next problem.

Playback Issues or Computer Locks Up

The frame interpolation method set in the project settings or for a clip can cause even very capable systems to come to a grinding halt if you are trying to slow down footage excessively and have options like optical flow or speed warp selected.  Give it time to render or change it to the nearest or frame blend.

Sometimes generating optimized media, using timeline proxy mode, or rendering the clips in place can help you achieve smooth playback and alleviate the pressure on your system.

Understanding the importance of frame rates and how DaVinci Resolve 17 works with high frame rate footage or deals with low frame rates when creating slow motion is essential. Once you understand these principles, creating amazing slow motion with DaVinci Resolve is very simple and effective.