capsule review

iMovie '08 Library Compressor 1.2

Like it or not, iMovie '08 is the future of iMovie. And, truth be told, I actually like it. Not in comparison to iMovie HD, but as an easy-to-use movie-making program, iMovie '08 is actually pretty good.

One useful feature of iMovie '08 is that, like iPhoto, it keeps a library of all your DV clips handy and available, regardless of which project you’re currently editing, so you have to import each clip only once to make it available to any project. The downside of this approach is that your iMovie Events folder, which contains all your imported DV footage, can quickly grow to ginormous proportions—DV files are big .

One solution to this dilemma is Nik Friedman’s iMovie '08 Library Compressor 1.2 (   ; free). This AppleScript-based utility uses the H.264 codec to compress the DV files in your iMovie Events folder; since iMovie '08 supports H.264 video, you can still use these smaller files in your projects.

iMovie '08 Library Compressor

To use Library Compressor, first quit iMovie '08 if it’s running. Then launch Library Compressor, read the informational message, and click on Continue; navigate to your iMovie Events folder in the resulting dialog and click on Choose. You’ll then be able to choose the quality of your converted video; here’s what each of these settings means, according to the developer:

  • Best: H.264 compression at maximum quality, with 16-bit Apple Lossless audio at 48khz—approximately 10% compression.
  • Better: H.264 compression at high quality, with 16-bit PCM audio at 48khz—approximately 66% compression.
  • Good: H.264 compression at medium quality, with 16-bit AAC audio at 48khz, 160kbps—approximately 80% compression.
  • Low: H.264 compression at low quality, de-interlaced, with 16-bit AAC audio at 32khz, 128kbps—approximately 93% compression.
  • Custom Settings File: Using the included Save Quicktime Export Settings File script, you can create your own QuickTime export settings file and then choose that settings file here.

The Better setting is, in my opinion, a very good compromise between space savings and video quality.

iMovie '08 Library Compressor Settings

Click on Select and the conversion process will begin. Library Compressor uses QuickTime Player to do the actual conversion, so you’ll see the Player window, with the Exporting Movie progress bar, for each clip. As with most video conversion, the process can take quite a while; how long depends on the speed of your Mac, the chosen compression settings, and how much video is in your iMovie Events folder. As an example, I converted an Events folder containing 4.74GB of DV movie footage using the Better setting. On my first-generation MacBook Pro with a 1.83GHz Core Duo processor—one of the slowest Intel-based Macs—the process took approximately 49 minutes; I was left with 600MB of H.264 video clips. That’s an impressive reduction in space, and yet the resulting video clips were barely distinguishable from the originals, even when viewed full-screen.

At the end of the conversion process, Library Compressor sets the creation date for each converted file to that of the original, so that your newly-svelte video clips are organized in the correct order in iMovie '08’s library. Your original DV files are moved to a folder called iMovie DV Archive in the same directory as your iMovie Events folder. If you’re satisfied with the quality of the compressed video files, you can delete this Archive folder. (I burned mine to DVD, just in case I ever needed any of the originals.)

Note that because Library Compressor converts only .dv files, you can run it at any time on your iMovie Events folder; it will convert only the .dv files you’ve added since the last time you ran it.

Library Compressor Caveats

There are a few considerable caveats to using Library Compressor. The first is that it works only if you’ve purchased QuickTime Pro, since the free version doesn’t export video. The second is that you also need to have the SetFile utility, part of Apple’s Developer Tools, installed; Library Compressor uses this utility to set the creation date on the resulting video files. (You don’t have to install the entire Developer Tools package; just need the SetFile utility. You can get this from your Mac OS X Install disc. On the Leopard disc, open Optional Installs, then open Xcode Tools, and then double-click on XcodeTools.mpkg; use the Installer’s Customize screen to choose just UNIX Development Support. On the Tiger disc, open Xcode Tools and then double-click on XcodeTools.mpkg; use the Installer’s Customize screen to choose just Developer Tools Software.)

Finally—and this the most important caveat to keep in mind—because you’re replacing video clips, any project that references those clips will need to be rebuilt using the new clips. So unless you want to reconstruct your movie projects, you’ll want to use Library Compressor only after you’ve completed and exported any project that’s currently in progress. (Or, if you’re just starting new projects, run Library Compressor before starting to work on those projects, so you’re using the compressed video from the start.)

On a functional note, iMovie '08 Library Compressor generally worked well for me, although on one occasion the program gave me an AppleScript “timed out” error, forcing me to start over. And because the process of converting video is slow, if you’ve got a slew of .dv files in your iMovie library, I recommend starting the process at night when your Mac will have plenty of “alone time.”

Of course, you could perform the same tasks as iMovie '08 Library Compressor, manually, using a video-conversion utility such as VisualHub (   ) and a third-party file utility such as FileXaminer; in fact, VisualHub’s actual video-conversion process is usually faster than QuickTime Player’s. However, Library Compressor makes the process easier, and its built-in date-setting feature is more convenient than having to note the original creation date of each DV clip and then using a utility to reset the date on the resulting converted-video files. iMovie '08 Library Compressor is a nifty utility and a good example of what you can do with a bit of AppleScript ingenuity.

iMovie '08 Library Compressor requires iMovie '08, QuickTime Pro, and Apple’s SetFile utility.

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