When Apple released iMovie 3 as part of iLife last year, the user-friendly video-editing application landed with all of the grace of a belly flop. For many users, iMovie 3 was glacial, unresponsive, and buggy. In fact, it wasn't until version 3.0.3, released six months later, that the program's performance improved enough to make it a viable video editor. And even then, several significant bugs, such as audio glitches during export, continued to plague some users.
In contrast, iMovie 4 is more of an amateur swan dive: beautiful and graceful for the most part, but still in need of improving its form. Apple has added some welcome new features -- most notably Direct Trimming -- and improved the overall editing experience. But while it's faster than its predecessor, iMovie 4 still suffers from performance issues.
Until version 4, iMovie was a destructive video editor: when you cut unwanted frames from a clip, those frames were moved to iMovie's trash. The only way to regain this footage later, if you discovered that you'd made a mistake or that you needed additional frames, was to use the Restore Clip Media command -- assuming, of course, that you hadn't emptied iMovie's trash in the meantime. But the Restore Clip Media command resurrected the original clip in its entirety, even if you needed only to gain two or three seconds of footage.
With the introduction of Direct Trimming, iMovie 4 joins the ranks of nondestructive editors such as Final Cut Pro and Final Cut Express. Instead of hacking unwanted footage off a clip, you now simply hide the frames you don't want to use by dragging the edges of the clip inward (much as you'd roll up a parchment scroll to see just a certain part). Later you can refine your edits to include previously removed frames by clicking and dragging the clip's edges to a new position.
Although Direct Trimming is a welcome addition, it tends to make the timeline feel crowded. As you trim footage from one clip, the clips around it react by scooting in or moving out to fill the space. All this movement can make it hard to maintain perspective on the clip you're editing. If you prefer a little breathing room while you edit, you can prevent adjacent clips from filling the gap by pressing 1 while dragging a clip's edge. You'll then be left with an empty spot in the timeline where the extra footage used to live. Later, if you want to remove this gap, switch to the Clip Viewer (1-E) and delete the clip of black frames that marks the empty space. This will bring the adjacent clips back in line.
Direct Trimming has one important drawback: emptying the trash will delete all the trimmed footage from your project. To play it safe, avoid emptying the trash until you've exported your finished movie to its final format.
Catch an Audio Wave
iMovie 3 let you edit volume levels within clips. With iMovie 4, Apple has expanded this feature by giving you the option of viewing audio-track waveforms -- visual representations of sound -- in the Timeline Viewer. It's now much easier to isolate unexpected loud noises and adjust volume to compensate. But because iMovie stores a clip's audio on the same track as its video, you'll have to extract the clip's audio to see its waveform. This could be a problem if you have audio content on both of iMovie's two audio tracks.
Another way that iMovie engages your ears is with audio scrubbing. Press the option key while dragging the playhead in the Timeline Viewer to hear audio at the speed you're dragging. While that can be helpful, Macworld's tests showed that audio scrubbing had a noticeable lag on a 1.25GHz PowerBook G4 and a dual-2GHz Power Mac G5, so the feature was mostly ineffective.
Navigation and Sharing
iMovie 4 also includes several smaller -- but much appreciated -- improvements that help make editing less time-consuming and mouse-intensive. For example, you can now select several noncontiguous clips and apply changes to them as a group. This is great if you need to apply a color-correction or soft-focus effect with the same settings to several clips at once, or if you need to extend several transitions of the same type by two seconds.
A new Timeline Snapping feature pulls the playhead to the closest edit point, making it easier to align video and audio. The playhead turns yellow and triggers a sound (optional) when it has been snapped to an editing point.
Thanks to new View menu options and their keyboard shortcuts, you'll spend less time scrolling through timelines. Press Command-Option-P to jump to your playhead, Command-Option-S to jump to the currently selected clip, or Command-Option-Z to zoom in to the current selection. You can also set bookmarks to indicate a scene you're working on, and then jump back to it later using keyboard shortcuts. To quickly switch between the Timeline Viewer and the Clip Viewer, just press Command-E.
Apple also revamped the interface for publishing your movies. Using the new Sharing command, you can opt to send your movie or selected clips to your camcorder, e-mail application, .Mac home page, or Bluetooth device (such as a 3GPP-compatible cellular phone), or export a QuickTime movie. iMovie then applies preset compression settings for each type of output.
Of course, all the new features in the world won't help you if the program is too slow. And when it comes to speed, iMovie 4 had mixed results.
On the main testing machine (a 1.25GHz PowerBook G4 with FireWire 800), iMovie 4's performance was, overall, much faster than that of iMovie 3 -- although it was still slower than that of iMovie 2. In version 4, scrubbing through a movie was snappier, and rendering times for transitions, titles, and effects all seemed to be improved. In fact, my footage actually began playing when I clicked on the Play button. (If that sounds self-evident, you must have missed iMovie 3.)
However, on an older, 400MHz Titanium PowerBook G4, iMovie 4 didn't fare so well. Although not as slow as in iMovie 3, playback in iMovie 4 stuttered frequently, and the spinning beach ball appeared more frequently as the program chewed on various tasks. On the bright side, the stuttering seemed more consistent than in iMovie 3, evenly dropping a regular number of frames instead of inexplicably freezing up. However, this also occurred when I exported the movie back to the camcorder's tape; encountering jumpy playback during the editing process is one thing, but having it in the final movie is unacceptable.
On both machines, performance degraded with longer, more-complicated projects. Although there was less performance degradation on the 1.25GHz machine than on the 400MHz Mac -- which slowed to an unbearable crawl -- both machines struggled with a project containing nearly two hours of footage. Apple's iMovie system requirements broadly call for a PowerPC G3, G4, or G5 processor, but I can't imagine running iMovie effectively on anything less than 800MHz.
Macworld's Buying Advice
If you've never used a nondestructive video editor such as Final Cut Express, it's hard to appreciate the full benefit of Direct Trimming -- but you will. All in all, iMovie 4 is an admirable upgrade to Apple's flagship digital-hub application. However, the application's overall performance still lags -- particularly on older Macs.
Snap to It You can turn Timeline Snapping on in the iMovie preference pane if you want, but save yourself the trip: instead, hold down the shift key as you drag the playhead in the timeline viewer. This will enable snapping for that operation only.Seeing Your Sound In iMovie 4, you can see the audio waveforms, so you can detect potential problems such as loud outbursts from crowds of people.
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