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.


Anonymous said...

Do you think Imovie 09 work with FCE version 4? Perhaps you could look into.

Aaron said...

I am fairly certain that the ability to export a FC XML file has been preserved. (Share -> Export Final Cut XML...) This basically creates a reference file you can import into FC that tells it when the cuts begin and end. None of the titles, additional audio tracks, effects, or Ken Burns settings will make the trip. All transitions will show up as cross dissolves.

The reason this still might be worth the effort is because the skimming feature in iMovie '08/'09 makes rough cutting super easy. You can do a rough cut, then export the XML file to tell FC where are the cuts take place. All of the finish editing can then be done in FC.

There most likely won't be any more compatibility than that. Hope this answers your question. :)

talandisjr said...

First of all, I'm an avid iMovie user/fan, so discovering your site has made my day. Wow! Thanks for all you do. You are helping video papas like me the world over. I'm really grateful to have found this place.

As an English teacher in Japan, I also use iMovie a lot with my Video Production students. They pick it up real fast and are able to produce simple projects that enable them to use English in creative ways. One problem I've encountered is trying to manage multiple projects on multiple machines, as well as finding time for importing footage.

With regards to image stabilization (a feauture I'm extremely excited about), one concern I have is over the amount of time it will take for processing. I can see that a bit of pre-planning and time management will be needed. For example, I can see myself doing all the importing/stabilizing in one step the night before, when no one is using the computers. Of course this won't always work, but it's something I'll be doing as much as possible.

Anyway, thanks again for this site. I've subscribed to the feed and am looking forward to becoming a regular viewer/commentator.

Toyama, Japan

Sam Colon said...
This comment has been removed by the author.
Sam Colon said...

How do you convert an Mpeg to Mpeg3 using iMove '09?