Randy from the iMovie team read my recent post on image stabilization and wanted to pass on some other things that are worth knowing about the way it works in iMovie '09.
Not Just a Zoom
The stabilization feature in iMovie '09 does more than just a simple zoom, which could be understood from my original post. iMovie primarily rotates and moves each frame to keep the objects all the in same place, which is quite a bit more sophisticated. Once the frames are moved and rotated, iMovie applies the amount of zoom necessary to cut off the black edges created by the correction. I suppose this could still be called a corrective zoom, but Randy's explanation is a lot more clear.
Two Things That Might Look Worse
In the same way shaky video can obscure what you want people to see, it can also hide things that you'd rather keep hidden. Once iMovie works its magic on your shaky footage, there are two other visual problems that will become much more noticeable.
Motion Blur
Unless you have a camera that shoots at really high framerates, it is possible to swing your camera around enough that the pixels will actually become blurred. Although iMovie can stabilize the frames relative to each other, it can't erase the blurriness of individual frames. Stabilized footage with blurry frames might look like the camera is moving in and out of focus.
CMOS Jello
If you are shooting video with a CMOS camera, like the new Nikon D90, your video is being shot with a rolling shutter, which means the sensor data reads from the top of the sensor to the bottom over a (very short) period of time. If the camera is moving during shooting, the results of a rolling shutter can make the world look like it's suddenly made of jello (link via Daring Fireball). Randy notes that stabilization can make the jello stand out and look especially jiggly. Because the overwhelming majority of video cameras and still cameras that shoot video use CCDs rather than CMOS sensors, most cameras will not suffer from the jello problem.
See It in Action
Randy was kind enough to send a link to some of his Africa footage that he used in the Macworld keynote. For the curious, he filmed with a Panasonic SD-5 (a CCD-based camera). Everything was shot hand-held, no tripods, and was later stabilized and edited in iMovie. Thank you, Randy, for the great information. It looks like it was a great trip!
Quick Look: More on Image Stabilization
Quick Look: Image Stabilization
This post has some updated information you can read here.
One of the remarkable new features in iMovie '09 takes the shaky, handheld video we all shoot, and makes it look like you lugged a steadicam around Disneyworld with you. In previous versions of iMovie, you'd have to buy a third-party plugin for this sort of thing. Despite having to wait a few more weeks before we can all put iMovie '09 to work, there are some things we know about its image stabilization effect that are worth mentioning.
Corrective Zoom
The stabilization feature in iMovie '09 works by applying a corrective zoom. If you look at this screen grab from Apple's tutorial video, you can see that the stabilized video has zoomed in on the scene. The dead tree in the middle of the shot is closer, and the trunk of the large tree on the right has been pushed out of the shot. A corrective zoom works by trimming the shake off the edges of each frame, preserving just that which can be seen in all of the frames.
This means there will inevitably be shaky footage that iMovie can't correct. (If I wildly swing my camera around, all the zooming in the world can't correct that amount of motion.) Exactly how far in iMovie is willing to zoom is something we will have to wait and see.
From what I've been able to tell, the zoom that iMovie applies will only ever be the minimum necessary to stabilize the shot. If I select a range that is relatively stable, the zoom will be slight. If I add footage to my range that is shakier, iMovie will zoom in even more. This is the reason that iMovie doesn't preview the stabilization effect while you skim your footage in the event browser. Without knowing the start and end point you have in mind, iMovie doesn't know how far to zoom in. Clips added to your project don't have this problem.
Processing Time
iMovie has to analyze footage in order to apply the stabilization. Apple has warned all of us about this several times already, but I don't know exactly how long it takes for a given length of footage. I would image it's long enough that you may want to take a break from you Mac when you set it to process.
The nice thing is that this processing time is voluntary (unlike thumbnail generation). If you don't want to stabilize your all of clips, you don't have to. You simply select either the clip or the entire events you want processed, then tell iMovie to get to work with a menu command. After it is done, iMovie '09 will also mark footage that is too shaky to correct, saving you the time of adding it to your project.
Most of the quality in home video projects comes not from the flashy effects, but from the little things like lighting, sound, and the steadiness of the shot. The fact that iMovie '09 fixes one of these issues so simply is really impressive.
How to Use Quicktime Video Effects
If iMovie is a Boy Scout, QuickTime is the Swiss Army knife. Where iMovie's powers fall short, the built-in QuickTime features take up the slack. I have used it for a few different workarounds on this blog. Well, it's time to add one to the list.
Well, what iMovie ditched, QuickTime lovingly stuck in its back pocket. Here is how to use QuickTime video effects.
Preface
Because of their current location in iMovie, you cannot apply video effects as easily before. In fact, you can only apply them to a clip you are exporting as a Quicktime movie, a step usually taken at the end of an editing project. Let’s look at how QuickTime video effects work, then discuss a creative way to use filtered clips in an active project.
About QuickTime video filters
Quicktime, Apple’s video workhorse, lies at the heart of iMovie. It is generally the case that if Quicktime can do it, then iMovie can do it. For example, if Quicktime can play a particular video format, then iMovie can probably not only play it, but also edit it.
Quicktime is also capable of applying a variety of filters to video. These filters can do simple tasks like sharpen and blur, or they can do very complicated things like alpha gain. The filters most people would be interested in are:
• Blur will soften your footage;
• Edge detect creates outlines of the subjects in your footage;
• Emboss makes your footage look like it was carved into a sheet of metal;
• Sharpen crisps up blurry footage (as much as is possible anyway);
• Color tint will make your footage turn black and white, sepia tone, cobalt, or like it was run through an x-ray machine;
• Film noise takes modern footage and makes it look like it sat in your attic for 20 years; and
• Lens flare adds a cool looking light flare that progresses across your footage.
A Disclaimer
I assume no responsibility for your movie looking amateurish and unprofessional due to a failure on your part to apply video effects judiciously. With great power comes great responsibility. Don't emboss your whole movie just because you think it looks cool. If an effect isn't helping you tell your story, do us all a favor and leave it out.
Applying a video filter
As mentioned above, these filters can only be applied when you are ready to export a project as a Quicktime movie. This means that whatever video filter you apply will be applied to your entire movie. You can also only apply a single video filter to footage, for each time you export it anyway. That said, let’s walk through the steps for doing it:
1. Export your movie as a Quicktime movie.
This is done by selecting Share-->Export using Quicktime.
2. Select “Movie to Quicktime Movie” and click the Options button.
This setting from the Export pulldown menu is the ultimate custom Quicktime setting. All the other options in that list are basically just (very) convenient shortcuts to what you can do with this setting.
3. Click the Filters button.
This is where you’ll find the video filters discussed earlier.
4. Select the video filter you want to apply, then click OK.
Each filter has its own settings. You can just accept the default settings, or you can adjust them to get the desired effect. The filters window provides a tiny preview window in the bottom right to help you see the results.
5. Adjust any other video or audio settings, then click OK.
Remember when I called the other export options convenient? I wasn’t kidding. If you find yourself lost with all the confusing options in this process, you’re not alone. There are some very advanced tools in here.
6. Select the name and save location for your movie, and click Save.
iMovie will go through the process of exporting your movie, including the video filter you applied. After it has finished, you can find your filtered movie in the place you told iMovie to save it.
Using Video Filters in an Active Project
What if you want to apply one of these filters to a single clip within a movie? You can’t do that by exporting the movie itself, because iMovie will apply the filter to all of your movie’s footage. The trick is to create a separate project containing just the clip you want to filter. Export this project using the steps listed above. Add the exported footage back into iMovie using the Import Movies option from the File menu. Once you’ve added the filtered footage into your Event library, just add it to the project that needed the filtered footage.
Note: When you are exporting clips to bring back into your project, you should probably export them in the format of your original footage. This can be tricky if you are unsure of what format to use, especially because this export method will overwhelm you with options. If you aren’t sure what format to use, find the original footage in your iMovie Events folder and open the footage in QuickTime player by double-clicking on the footage file. Press Command-I or select Show Movie Inspector from the Window menu. The window that pops up will tell you the video format you should use when you export the footage from iMovie.
There's a reason carpenters don't rely on Swiss Army knives.
If you find yourself underwhelmed by what you've just learned how to do, you aren't alone. The problem with Swiss Army knives, after all, is that they just barely get the job done, even when they have the right tool built in. QuickTime is great and all, but thankfully iMovie has relearned some old (and new) tricks when it comes to video effects.
How to Add Black Space
Unlike previous versions of iMovie, you cannot drag clips apart in the timeline to create black space between clips. How do you drive home the drama without some black space to let the moment sink in? Well, here's one way...
Go to the titles button on the right side of the iMovie window. Pick the Centered title and drag it where you need some black space.
Once you have your title in place, select the text in the preview window on the right. Delete it all and leave it blank so it looks like this:
This blank title serves as an adequate substitute for black space. However, you probably want to adjust the timing of it to fit your movie's needs. Unfortunately, although you can just drag to adjust the timing of the title (which isn't there because you deleted all the text), you cannot drag to get the clip itself to the desired length. To adjust the timing of the clip itself, you will need to choose the "Set Duration..." option. You can find it in the Edit menu...
In the contextual menu you get by right-clicking or control-clicking...
By clicking the little clock icon on the clip...
Or you can just hit Command-R.
Once you do, a little window pops down from the top that lets you type in a numerical value, in seconds, for how long you want the black clip to last.
This process will probably take some trial and error, but hopefully you can get the length you want without too much trouble.
In the end, your project will look something like this:
If anyone figures out an easier or more accurate way to get just the right amount of black space, please share it with us in the comments!
