If you are looking for a free solution to slow down 60 frames per second (FPS) AKA 60p footage to get a slow motion effect on your Mac, you can download and install the freeware video de-interlacer JSE Deinterlacer. This will allow you to export your video at a slower framerate like 24FPS through stretching the film to be double length and use the additional frames shot to fill the time, kind of like stretching out  a coiled spring. Fast frame rates are now available from the Canon 7d and 550d cameras with signs that many more cameras follow suit by offering this feature, thus the reason to offer a no-cost option of how to handle the footage.

Step one: Import

Specify the film you wish to process, thats it, use the default values for everything else.

Step Two: Project settings

This is the main part we need to care about. Ensure you have Deinterlace selected from the options and Both fields and Double movie duration checked. Normal height and Adaptive will be selected by default, this is what we want.

Step 3: Output

We specify your desired output video location and set the settings for the movie that is exported. Select the export option and choose Quicktime Movie.

Step 4: Movie Settings

If you are explicitly looking for slowed speed sound select the sound checkbox and your audio channel will be exported, else just unselect this. Click settings to choose more specific output options.

Step 5: Video Settings

Choose MPEG-4 Video as your compression, choose a frame rate of 24 – 30 using keyframes every 24 frames. The other settings are just for how high you want quality to be.

Step 6: Finishing up

Now you can return back to the output screen and select Ok, this will start the conversion process off that could take some time depending on the size of your source video. Once you have converted your video, you can take it into your choice of video editing suites such as iMovie.