To add video effects, go to the top of the video output on the iMovie video editor. You’ll see a drop-down menu for “Video Effects”.

Choose either the sound or video effect of your choice.

To increase or decrease the speed of your video, right click on the clip and go to “Show Click Trimmer” on the dialogue.

You will have unlocked a new icon at the top of your preview video – “Speed”! This will be the 7^th icon on the top right.

Click on it and there you change the speed from options “Normal”, “Slow”, “Fast”, and Custom. You can also reverse your video here, if you’d like.