MacMost: iMovie

Resizing and Positioning Green Screen Video In iMovie
You can't resize or position an overlay and also apply a green screen effect in iMovie at the same time. However, you can do the scaling positioning over a green background, export, and then use the resulting video in another project to get the same result.
Creating Video Scrolling Credits With Keynote
You can create professional-looking video end credits with Keynote using only a single simple animation on a single slide. You can incorporate a long list of names, and add shapes, photos or other elements into a group. The result is easily modified and exported as a video to bring into iMovie, Final Cut or any other video editing app.
Matching Clip Audio In iMovie
When you have several clips that you want to use in the same project in iMovie, sometimes you have to deal with different sound levels in each clip. You can use the Auto Loudness button to quickly adjust the volume in each clip. You can also manually adjust the volume in a clip or part of a clip. You can also use noise reduction improve the sound quality in a clip.
Rotating Video Any Amount
If you need to rotate video a small amount to correct a camera tilt or create a special effect, you can't do it with iMovie or QuickTime Player. However, you can use Keynote to rotate video. This involves a small Keynote project with just the video, plus a rotation, and then an export. You need to make adjustments to avoid leaving blank corners.
Rotate Video In iMovie and QuickTime Player
If you have video recorded in the wrong orientation, you can rotate it after you add it to the iMovie timeline. You can also change the original file by opening it in QuickTime Player, rotating it, and saving a new version. If you need to rotate video in Photos, you'll have to export the video, rotate it in QuickTime Player, and then import the new version back into Photos.
Export Still Frame Image From a Video
You can export a still frame image from a video many different ways with the software that comes with your Mac. If you are already in iMovie, you can use the sharing function to export an image from the current frame in the timeline or a library clip. In Photos you can save a frame in a video to your Photos library as a picture, and you can also copy the current frame and paste it into another app. The easiest way is with QuickTime Player where you can copy the current frame and then paste it into Preview or any other app that handles images.
iMovie Match Color
In iMovie you can force a video clip to more closely resemble another clip by using the Match Color tool. This simply adjusts the color of the first clip to match the colors in the second. You can use this to prevent jarring transitions between very different clips, or to match similar scenes that were shot using different light. You can also use Match Color with images or between video clips and images.
Fade Out Background Music in iMovie
If you add a piece of background music to your iMovie project, the length of the music may be longer than your video. You can set the music to fade out at the appropriate time by dragging the Fade Out dot to the left. You can use this technique whether you use iMovie's special background music track or attach the music to a clip in the main part of the timeline. You can also fade in and add other changes in volume at any point.
Selecting Clip Ranges In iMovie
In the past it has been tricky to select an entire clip or a range inside a clip in iMovie. With the latest version of iMovie, just clicking on a clip gives you the entire clip, and holding down the R key allows you to select a precise range from within the clip. This works in the timeline as well. The i and o keys can be used to adjust a range start and end.
iMovie Paste Adjustments
When you make a series of adjustments to a clip in the timeline in iMovie, it can be hard to replicate the exact same changes to another clip. You can use Paste Adjustments to copy one or all adjustments from clip to clip. This makes it easy to implement consistent settings across different parts of your project.
Creating Transparent Images With Keynote
If you need a transparent image, like a circle, arrow or piece of text, you would usually create it in a graphics app. However, there is a way to create transparent images quickly using only Keynote. You can then use these as overlays on other images in Preview or in iMovie.
iMovie Mirror Effect
You can combine two different techniques in iMovie to create a mirror effect where the same clip is displayed as a mirror image on the left and right.
Freeze Frame In iMovie
The Freeze Frame feature in iMovie allows you to easily stop the action and create several seconds of a still image in the middle of your video. You can use this for dramatic effect. You can also cut out the freeze frame portion and apply a filter or other effect.
Stabilize Video In iMovie
iMovie includes an easy-to-use function that lets you stabilize shaky video. It works best on video that is relatively still. You can make shaky video easier to view and appear more professional.
Create a Slideshow With iMovie In Less Than 3 Minutes
It is easy to create a slideshow with iMovie using a photo album. In less than three minutes you can import the photos, add transitions, insert titles, and include music. You can then export the slideshow as a video to use on YouTube, your social networks, or show during a presentation.
Understanding iMovie Projects and Events
It is easy to get confused between iMovie Projects and Events. Events can be used to store video clips which can then be used in multiple Projects. Clips can also be stored directly in a project.
Filling In the Sides of Vertical Video in iMovie
If you accidentally record video on your iPhone in vertical mode, you end up with two ugly black bars on either side of the video when viewing it on a TV. You can use iMovie to fill in those sides with an animated background, or a blurry copy of the same video. Take a look at a variety of techniques for dealing with vertical video in iMovie.
Creating Animated Video Overlays With Keynote
You can use Keynote's animations and special effects in your video projects. Just create the animation in Keynote over a green background. Then export as video and import into iMovie. Use the green screen overlay function in iMovie to place the animation over your other video.
Sharing Private Videos Using YouTube
Sharing videos via email, file transfer or using old technology like DVDs can be impractical. Uploading your videos to a service like YouTube that almost anyone can access is easy and useful. You can set these videos to be unlisted or private if you aren't interested in the general publicseeing them. YouTube videos can be viewed on computers, set-top boxes, TVs, tablets, phones. Plus, they can be high definition, giving them a big advantage over DVDs.
Moving Graphic Pointers In iMovie
Learn how to create a transparent graphic that you can then overlay in iMovie to point out an area of interest. You can then have that graphic move around on the video to follow a subject. You can use this to highlight something in the video, or hide a face or some other element.