Converting a regular video to slow motion with iMovie on Mac

By , Sep 1, 2016

iMovie Large Header

Slow motion videos are one of the fun aspects of using your iPhone for videogprahy. You can record videos in 120 or 240 frames per second and then watch it play back in a much slower manner than it typically would.

On the other hand, if you don’t use your iPhone to capture video, getting the video files from your other devices to transform into slow motion is a little trickier. Fortunately, iMovie for Mac can convert your videos into slow motion, and in this tutorial, we’ll show you how.

For example, I have a dash camera in my vehicle that I like to use and grab footage from, but as you can imagine, it doesn’t record in slow motion.

One night it just happened to be raining cats and dogs outside, and Florida lightning can get pretty intense. When I got home, I wanted to share the lightning I captured on video on Facebook with my friends and family, but I wanted to slow the video down so the lightning was easier to see.

For this, I used iMovie, a free download from the Mac App Store for anyone who has bought a Mac recently. If you haven’t bought a Mac recently, you’ll have to shell out $14.99 for the app.

Using iMovie to convert videos to slow motion

If you have iMovie on your Mac, just follow the steps below and you’ll have a slow motion videos in no time:

1) Launch iMovie on your Mac, and then click on the Import Media button.

iMovie Import Media

2) In the file browser, select the video file you want to convert to slow motion, then click on the blue Import Selected button.

iMovie Import Selected Video

3) Now the file is added to iMovie. You will now need to create a project. To do that, click on the Projects button.

iMovie Projects Button

4) In the prompt, give your project a name, and then click on the blue OK button.

iMovie Name New Project

5) Now that your project is created, you can begin editing the video by dragging it into your timeline. Once you do, click on the video to select it, and then click on the Speed button:

iMovie Add Clip to Timeline and Adjust Rate

5) This will show the speed-editing interface. Click on the Speed drop-down menu and change Normal to Slow.

iMovie Slow Motion Speed Mac

6) Your video will then be slowed down to half-speed, which doubles the video length. You can also slow the video down further by clicking and dragging on the speed slider:

iMovie slow motion speed slider

7) Once satisfied with the slow-down results, head to the Menu Bar and navigate to File > Share > File…

iMovie Export File Mac

8) Give the file the attributes you want, and then click on the blue Next… button.

iMovie Slow Motion File Attributes

9) Now choose a name for the file and a place to save it to, then click on the blue Save button.

iMovie Save New Slow Motion Video

And that’s all there is to it!

An MP4 video file will be added to wherever you save your file to, and when you play it, it will play in slow motion instead of standard motion.

The results

What would a video tutorial be without some before and after results? I was thinking the same thing…

Here’s the footage before the modifications, showing the normal speed:

Regular speed GIF

And here’s the footage after the modifications, showing the slow-motion speed imposed by iMovie on my Mac:

Slow speed GIF

The slower video just lets you see so much more of the lightning at a glance, allowing your mind to process more of it at once.

Sometimes you just need a quick and easy way to convert a standard speed video to slow motion, and since your iPhone may not be your only video-recording device, you may not always have slow-motion capabilities at your fingertips.

On the bright side, iMovie lets you add last-minute slow motion edits to your videos after the fact with very little hassle at all. If you don’t already have it, then head over to the Mac App Store and download yourself a copy of this incredibly useful software.

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  • leart

    out of topic, for who wants to give an opinion .. I’m considering to purchase a new old stock, ipad 3 new unused, still in ios 5.1 for 335$… is it worth it? 😀

    • rockdude094

      iPad 3 is incredibly slow, Id say go for the iPad 4

      • leart

        it’s not to have a fast device, it’s for the old ios and for the fact that is new 😉
        can’t find a new ipad 4 new.. this is a forgotten old stock in a big shop

      • rockdude094

        Oh true yeah then the iPad 3 would be perfect

      • leart

        I have already a mini 1 in ios 6 lol

    • Bugs Bunnay

      Why not

  • Mr_Coldharbour

    Could you make a tutorial on how to remove the black box / black bar in a video that was taken with an iPhone and edited in iMovie? Every time I take a video with my iPhone, transfer it to iMovie on the Mac for editing, it always exports with those hideous black bars on the sides as if it were cropped. Whether I choose the option to export in the highest possible resolution or not, I always get the black boxes / bars. Any way to get around that and export my newly edited videos at the same aspect ratio and resolution as when it was recorded? Please show me how to do this without any other 3rd party apps, I just want to do this on the Mac with iMovie. Help would be appreciated. Thanks!

    • Bugs Bunnay

      Mr coldharbour, you didn’t take a video vertically did you? If so you’ll have to change to the right resolution on imovie.

      • Mr_Coldharbour

        Yes, I was referring to vertical videos. Sorry for not being clear on that. So you’re telling me that I’ll have to deal with the black boxes if videos were taken vertically?

      • Bugs Bunnay

        On the contrary sir! You should be able to change the resolution on the settings or preferences. I haven’t used imovie, but i’m sure it’s there

      • Mr_Coldharbour

        I’m aware of the resolution change, I know my way around the essentials of iMovie. Though no where have I seen the ability to get rid of those black boxes when a video was taken vertically.

      • Bugs Bunnay

        What i meant was to change output video from 1920×1080 to 1080×1920. You are basically rotating it to match the vertical video

  • Bugs Bunnay

    Ah if it was rainning cats and dogs here in cali it would be a dream!

    • Agneev Mukherjee

      Ha ha!

  • Agneev Mukherjee

    Could you please share the Lightning video, Anthony?