If you need to stabilize a clip in your project, select the clip and then click the Adjust button in the iMovie toolbar. Click the Stabilization tool (Figure 9-1) and you’ll see two checkboxes: Stabilize Shaky Video and Fix Rolling Shutter.

Figure 9-1. The Stabilization tool in the Adjust toolbar offers two choices. The first stabilizes camera shake, and the second fixes rolling shutter problems (a.k.a. “jellyroll”). Turn on either checkbox (not shown) and you see these little spinners instead of the checkboxes—which let you know iMovie’s analyzing your clip so it can apply fixes.

Turn on the Stabilize Shaky Video checkbox and iMovie replaces the checkbox with a little spinny-thing to tell you it’s thinking, analyzing the clip’s frames so it knows how to stabilize them. If you’re stabilizing a long clip, don’t bother waiting for iMovie to finish. Carry on editing, and iMovie will eventually fully analyze and stabilize the clip.

Remove Stabilization

You may change your mind and decide that a clip looks better without stabilization. It can happen (see Fix Shaky Footage). Just select the clip and uncheck Stabilize Shaky Video in the Stabilization tool. The shake comes back.

Figure 9-2. Top: This clip has the stabilizing zoom set to 10%, so the video will be shakier, but you can see everyone. Bottom: This clip is zoomed 100% for the full stabilizing effect, but you’ve lost half a head and almost an entire 10-year-old.

And don’t worry about having to reanalyze footage if you change your mind yet again. Once analyzed, always analyzed.

There’s a second type of distortion you should know about, called jellyroll footage. It arises when you shoot with a camera that contains a so-called CMOS light-sensor chip. Most cameras these days, including iPhone and iPad cameras, contain this sort of chip. (In fact, fewer and fewer cameras use the alternative technology, called CCD, so odds are this section on jellyroll footage will apply to you.)

Unfortunately, CMOS cameras use a rolling shutter, which means that the sensor records an image starting at the top and working its way down to the bottom, really fast. If the camera moves too much as you film, the subject gradually shifts left or right as the sensor records the image.

The resulting image makes the world look like it’s suddenly made of jelly—a source of endless frustration and bewilderment to amateurs and pros alike. “Dang it!” they say, “what’s wrong with my camera?”

Unfortunately, iMovie’s stabilization feature tends to exaggerate this bizarre jelly effect.

Rolling Shutter Adjustments

To reduce the jellyroll effect, select the clip in your project and click the Adjust button in the toolbar. Under the Stabilization tool shown in Figure 9-2, check the Fix Rolling Shutter box. iMovie immediately gets to work analyzing the clip and will show a successfully checked box when it’s done.

The jelly effect is the product of how fast your camera’s rolling shutter works. Slower shutters need the High or Extra High settings in the Amount menu (Figure 9-3). Faster shutters can use the Low or Medium settings.

Less expensive cameras, like point-and-shoots, need the High or Extra High setting (they have slower shutters). Midrange cameras, like most consumer camcorders, typically need the Medium setting. Expensive cameras, such as DSLRs, generally get by with the Medium or Low setting because they have very fast shutters.

Tip

Of course, if you want to get precise adjustments, test things out with your own camera. Find a vertical, linear object like a telephone pole. Film it while you pan side to side. (Use a tripod if you want to be really exact.) Pan quickly enough to get the jellyroll effect going. Now just import and analyze the footage, add the clip to your project, and try different Amount settings until you get a nice, straight telephone pole.

Figure 9-3. The Fix Rolling Shutter setting helps reduce the jellyroll effect you get in footage shot by certain cameras. Once iMovie analyzes your footage, turn on the rolling shutter fix with this checkbox in the Stabilization tool. Set the level of adjustment (“Amount”) to best compensate for your camera.

The easiest of the Color Balance tools is the automatic one. When you click this to turn it on, iMovie will decide what balance it thinks looks best, using complex algorithms devised by very smart Apple engineers. Auto gets it right more often than not, so this should be your go-to tool.

Colors often change as you shoot, especially if you shoot outdoors. (A cloud passing in front of the sun can dramatically change how everything looks to your camera.) The Match Color tool gives you the chance to make up for this.

Once you click this tool (shown in Figure 9-5), iMovie previews the clip you’re editing on the right, next to the preview of a clip from somewhere else in your storyboard or the Event browser. Skimming around in your other clips will change the left-hand preview (Figure 9-5). Notice how your cursor turns into a dropper tool.

The idea is to pick a clip from a similar setting where the colors are just right. Once you find it, click with the dropper tool and iMovie shows what your edited clip will look like with the matched colors. Use the On/Off switch to see the before and after. Click the button to save your changes and the button to cancel.

Color balance is easiest when you have an anchor color to rely on. That color is good ol’ white. White light, scientifically speaking, contains all the colors in the spectrum, so a perfectly white object will reflect all those colors at once. With this knowledge in hand, iMovie can do really nice color balancing as long as you tell it what should look white.

When you click the White Balance tool, iMovie changes your cursor to a little dropper tool (Figure 9-6). Use it to click anything in your frame that should look white. Once you click, iMovie changes all the colors based on this reference point.

Figure 9-5. The Match Color tool shows the clip you’re editing on the right next to a reference clip from somewhere else in your movie. Skim around the clip to find the spot with the right color balance, and then click the clip. Click the button to close the Match Color tool.

Figure 9-6. Top: With the White Balance tool open, pick a spot in your clip that should look white (like the projector screen shown in this image) and then use the dropper to select it. Bottom: iMovie adjusts the clip’s colors so that the white part looks white and every other color matches as it should.

This tool works the same way as the White Balance tool, but instead of choosing something that should look white, you choose a spot on someone’s skin that should look like skin, like his face or arm. Of course, shading and natural skin color can alter what changes iMovie applies, but overall it does a pretty nice job for all skin types.

Sometimes your colors are fine, but the problem is too much or too little light. It can be a problem for all of a shot or different parts within a shot. In any case, making adjustments to the clip’s lighting can fix these problems.

The contrast tool can’t fix all lighting problems, however. Whenever you shoot video, your camera has to decide how much light to let in, based on the amount of available light in the room. Too much light can overwhelm your camera. It also can’t make up for too little light, like in a dark room.

In some cases, it can have too much light in one part and too little in another. If you video someone standing in front of a daytime window, for example, your camera has to make a choice. Does it let in lots of light to better see the person’s face, but in the process overexpose everything coming in from the window? Or does it dial down the sensitivity, making the window look normal but the person just a dark shadow?

iMovie’s contrast tool can do its best with problems like these, but ultimately it can only draw on whatever light your camera captured. Avoid these problems by making sure you film with adequate lighting. Preview your camera’s light sensitivity before you start filming.

Assuming your clip’s lighting is within iMovie’s reach, follow these steps to make contrast adjustments:

Figure 9-7. Top: Sometimes you shoot stuff that’s too dark or too bright—or both within the same shot. Use the leftmost slider in the Color Correction tool to make changes to the brightness and contrast of your clip. The middle point of the slider adjusts overall brightness. The left and right ends adjust lowlights and highlights, respectively. The half-moon buttons together change the contrast between light and dark. Bottom: Just a few changes can bring out details hidden in the shadows.

You can always come back and make more changes to a clip later; iMovie doesn’t do anything permanent to a clip’s contrast. To return a clip to its original appearance, click the undo button (the swirling arrow whose tooltip says “Remove color adjustments”) to the far right of the color sliders.

Sometimes what you’ve shot looks dull. Not because the clip isn’t interesting, but because the lighting washed out the colors. (Hazy weather or a lens flare can have this effect.) iMovie’s saturation slider can make up for this.

Click the Adjust button and then the Color Correction tool to show the middle of the three sliders (Figure 9-8). Dragging the slider to the left will strip a clip’s color, all the way down to black and white. Drag it to the left and the colors become much more vibrant.

Figure 9-8. Top: The wrong lighting or weather can make your footage appear washed out. Bottom: Dragging the saturation slider (the one in the middle) a bit to the right makes the blue sky and ocean in this clip far more vibrant.

You can undo any of these changes after the fact with the slider itself or the undo button on the far right.

Most light that hits your subjects isn’t pure white. It’s either on the cool side (bluer) or on the warm side (oranger). This difference is called color temperature. The warmth slider is a way to compensate for shots that are too cool or warm.

This slider basically works like the saturation slider, but instead of making footage bland as you drag it left, this makes everything more blue. Dragging it to the right turns everything yellowish-orange.

As always, you can make these changes and undo them later with the slider or the undo button to the far right of your color sliders.

Cropping, like any iMovie edit, is nondestructive. That is, you haven’t done anything permanent to the source video on your hard drive, and you can adjust or remove the cropping anytime you like.

To do that, just follow steps 1–4 on the previous page, resizing the white rectangle to the better size and position.

To remove the cropping altogether, click the Fit button in the Viewer.

When you rotate your video, you’re not changing the underlying footage. You can adjust or remove the rotation anytime. Click those rotation arrow buttons again until the video looks the way you want it to.