Slow motion works by capturing more frames per second than normal, then playing them back at standard speed

When you watch a slow-motion video, you are not watching something that was filmed slowly. You are watching video that was recorded at a higher frame rate — say 60 frames per second instead of the usual 24 or 30 — and then played back at normal speed. This stretches the same amount of action across more frames, making it appear to move slower.

If your video was already recorded at standard frame rate, you cannot create true slow motion after the fact without losing quality. What you can do instead is interpolate — have software guess what the frames in between should look like — or straightforward stretch the video by slowing playback speed, which makes motion blurry. The best slow-motion videos come from footage shot at high frame rates to begin with.

Key Takeaways

  • True slow motion requires video shot at 60 frames per second or higher; standard 24 or 30 fps footage cannot be converted to smooth slow motion after recording.
  • Most phones now record at 60 fps or 120 fps in their camera app, and many phones let you select slow-motion mode before you film.
  • On Windows, the Photos app can slow down video playback speed; on Mac, iMovie does the same with a slider.
  • Free desktop software like DaVinci Resolve and Shotcut can interpolate frames to create slow motion from standard footage, though results vary depending on motion complexity.
  • Slowing down video that was not shot at high frame rate will look blurry or stuttering, not smooth.

Recording video at high frame rates on your phone

Most modern smartphones can record at 60 frames per second or higher. On iPhones, open the Camera app, tap the video mode, and look for a frame-rate selector in the top right corner — it usually shows "1080p 60fps" or similar. Tap it to see your options, which may include 120 fps on newer models. On Android phones, the location varies by manufacturer, but look in the Camera app settings or the video mode menu for a frame-rate or resolution option.

Some phones also have a dedicated slow-motion mode that automatically records at high frame rate and plays back at slow speed. On iPhones, this is a separate mode in the Camera app labeled "Slo-Mo." On Android, check your camera app for a "Slow Motion" mode. These modes handle the frame-rate recording and playback automatically — you just film normally and the phone does the rest.

The trade-off is file size. A 60 fps video takes up roughly twice as much storage as the same video at 30 fps. If your phone is running low on space, record at 30 fps for normal speed and reserve 60 fps for moments you know you want to slow down.

Slowing down video on iPhone or iPad

The built-in Photos app on iPhone and iPad can adjust playback speed. Open the video in Photos, tap Edit, then tap the three dots menu and select "Video Speed." A slider appears at the bottom — drag it left to slow down, right to speed up. You can set it anywhere from 0.25x (one quarter speed) to 2x (double speed).

This method works on any video, but the result depends on how it was filmed. If the video was shot at 60 fps or higher, slowing it down will look smooth. If it was shot at standard 30 fps, slowing it down will look choppy or blurry because the phone is stretching the same frames across more time.

For more control, use iMovie, which is free on Mac and iPad. Import your video, select it in the timeline, tap the speed icon (it looks like a speedometer), and drag the slider. iMovie also lets you reverse video and create variable speed effects where different parts of the video move at different speeds.

Slowing down video on Windows

The Photos app on Windows 10 and 11 can adjust video speed. Open the video in Photos, click Edit & Create, then select Edit. Click the speed icon in the toolbar — it looks like a speedometer — and choose from preset speeds (0.25x, 0.5x, 1x, 1.5x, 2x) or drag a slider for custom speeds.

For more detailed control, use the free software DaVinci Resolve, which runs on Windows, Mac, and Linux. Import your video, drag it to the timeline, right-click it, select Retime Controls, and adjust the speed slider. DaVinci Resolve also has an Optical Flow option that attempts to interpolate frames — creating new frames between the original ones to make slow motion smoother even if the video was not shot at high frame rate. Results vary; straightforward motion (a person walking) interpolates better than complex motion (water splashing).

Using frame interpolation to create slow motion from standard footage

If your video was shot at standard frame rate and you want smooth slow motion, frame interpolation is an option. Software analyzes the motion between frames and creates new frames in between, effectively increasing the frame rate. This works reasonably well for straightforward, predictable motion but struggles with fast movement, occlusion (one object hiding another), or complex scenes.

DaVinci Resolve's Optical Flow is the most accessible free option. Import your video, slow it down to the speed you want, then right-click the clip and enable Optical Flow. The software will process the video and generate interpolated frames. Processing takes time — a one-minute video might take several minutes to render. The result is usually smoother than straightforward stretching but not as smooth as video shot at high frame rate.

Other free options include Shotcut, which has a speed effect with frame interpolation, and FFmpeg, a command-line tool that can interpolate frames using algorithms like RIFE or DAIN. These require more technical setup than DaVinci Resolve but offer more control.

Why slowing down standard footage looks blurry or stuttering

When you slow down video that was shot at 30 fps without interpolation, you are stretching 30 frames across more time. If you slow it to half speed, each frame now displays for twice as long. Your eye sees the same image sitting still for longer, then it jumps to the next image. This creates a stuttering effect.

Some software tries to smooth this by blurring between frames, which makes motion look streaky rather than smooth. Neither effect looks like true slow motion. True slow motion has more frames to begin with, so the motion is already smooth — slowing playback just stretches that smoothness across more time.

This is why the best approach is always to record at high frame rate if you know you want slow motion. Most phones make this straightforward — it is just a setting change before you hit record.

Exporting your slow-motion video

Once you have edited your video to the speed you want, you need to save it. In the Photos app on iPhone or iPad, tap Done to save the changes to the original video. On Windows Photos, click Save a Copy to export the edited version.

In iMovie, click File, then Share, and choose your destination — you can save to your computer, send to Photos, or upload directly to some platforms. Choose a resolution and quality level. Higher quality means larger file size.

In DaVinci Resolve, go to File, Export, and choose your format. For most purposes, H.264 video codec at 1080p or 4K resolution works well. DaVinci Resolve will render the video, which can take time depending on length and interpolation settings.

Frequently Asked Questions

Can I make a video slow motion if it was already recorded at normal speed?

You can slow down the playback speed, but it will not look smooth. If the video was shot at 30 fps, slowing it will look stuttering or blurry. Frame interpolation software can create new frames to smooth it out, but results depend on how complex the motion is. straightforward motion (a person walking) interpolates better than fast or chaotic motion.

What frame rate do I need to record at for smooth slow motion?

60 frames per second is the minimum for noticeably smooth slow motion. 120 fps or higher looks even smoother. Most modern phones can record at 60 fps or 120 fps — check your camera app settings before you film.

Does slowing down video reduce quality?

Slowing down video itself does not reduce quality if the video was shot at high frame rate. The frames are already there; you are just playing them back slower. If you use frame interpolation to create new frames, quality depends on the software and the complexity of motion in the video.

What is the difference between slow motion and just playing video slower?

Slow motion is video shot at high frame rate and played at normal speed — it has many frames per second of action. Playing normal video slower just stretches the same frames across more time, making it look stuttering. True slow motion looks smooth because there are more frames to show the motion.

Can I undo slow-motion edits on my phone?

On iPhone, open the video in Photos, tap Edit, tap the speed icon, and drag the slider back to 1x (normal speed). On Android, the process varies by phone, but most phones let you undo edits in the Photos or Gallery app. If you saved a copy, the original is usually still there.