Rule No. 1 in most event videography is to use a tripod, monopod, or other steadying device whenever possible. While most of us follow this rule most of the time, there are always candid shots and audience B-roll that are challenging enough to get without a support device, and even the best among us may end up with hand-held shots that are shakier than we’d like. At some point in every other project or so, you’ll likely find yourself wishing for some form of image stabilization software.
Depending upon the editor you use, there’s a good chance you already have a potential solution in your shop. For example, Adobe editors may have the SteadyMove plugin from Premiere Pro 2.0, which works in Premiere Pro CS3 if you drag it into Premiere Pro CS3’s plugin folder. After Effects also includes a very capable image stabilization utility, though it’s also very, very labor-intensive (like much of After Effects). For Mac-based editors, Apple debuted SmoothCam in Final Cut Pro 6. Though very slow and often cumbersome to use, SmoothCam produces very good results.
Now for Windows shops, there’s Mercalli from proDAD, the folks who brought us the Vitascene special effects plugin that I reviewed in July 2007. The program is available in two versions: Mercalli Light ($59) for SD/DV and Mercalli Expert ($119) for SD/HD. There are trial versions for both that include the full-feature sets, but your output will be watermarked. The Expert version is also more configurable, as I detail below. proDAD has plugins available for all versions of Premiere Pro and Premiere Elements, as well as Avid Liquid 7.x and Canopus EDIUS 4.x.
I found Mercalli easy to use and quite effective. It had the broadest range of useful options in any tool that I’ve seen, though, as always, there were some bumps in the road. In this review, I’ll describe how Mercalli works, briefly compare/contrast the operation of the other products I mentioned, and describe my tests and results.
To see Jan Ozer's video tutorial on using ProDAD Mercalli, click here to go to EventDV-TV, select the Tutorials tab, and scroll down.
How They Work
All anti-shake tools work similarly under the hood, though user interfaces vary widely. At their core, they attempt to detect shakes and other undesirable motion, then remove it by shifting the frame around to compensate. For example, if you jerked the camera to the right, the software would shift the frame to the left. Of course, this would leave a black edge on the right that would vary in thickness based upon the extent of the motion. To eliminate the black edge, anti-shake tools typically zoom into the video, much like older digital image stabilization functions used to do on inexpensive camcorders.
Though the basic functions are similar, the four tools I analyzed all work differently, and understanding their mode of operation is instructive. After Effects is the most basic. When you apply the stabilize function, After Effects displays a little box that you attach to a stable object in the frame. If you click Analyze, After Effects will attempt to follow that object, but it generally does a poor job of it. You end up shifting the box back to the tracked object manually, frame by frame.
For example, one of my test clips was a bridal 180° shot in which I half-circled the bride without a stabilizing device. With After Effects, I had placed the little tracking box on the bride’s left ear. I had to adjust the tracking box every frame or so, which gets old—even during a 7-second test clip.
The result, of course, is as good as your patience and time investment since you can adjust out each shake perfectly. However, after you apply the effect, After Effects forces you to make the decision of when and how much to zoom in, which other programs deal with automatically. Overall, you can produce the best possible result in After Effects, but it’s very labor-intensive, which sounds more appropriate for high-budget movies than event videography.
At the other extreme are SteadyMove and SmoothCam, which for the most part work automatically. For example, the SteadyMove plugin has two controls: Smoothing and Max Correction. SmoothCam has five controls: Scaling, Transitional, Rotation, Scaling Smoothness, and Mix. While useful, these controls are not scene-specific, so it’s tough to know which to apply to produce the best result with your problem footage. Basically, you must apply the effect, render the results in the timeline, preview, and adjust as necessary.
In contrast, Mercalli provides 30 presets in six categories, including some that will sound immediately useful, like "Shoulder Cam: reduce walking movement," "Rescue: smooth highly shook or jittery record," or my favorite, "Tripod: simulate almost stationary camera" (Figure 1, below). There are also some very content-specific presets like "In Practice: tracking a flying object in the sky" and "In Practice: smooth tracking shot from a bumpy car drive."
The presets adjust eight different sets of parameters, which include Particular Distinguishing Characteristics (detect silhouette only, object contours, and details), Camera Stabilization (soft, smooth, or static), and Camera Motion (allow for inclination compensation only, title compensation, or tilt and zoom). There are also settings for Important Picture Area (border, neutral, center) and Motion Detection (more quickly, more valid).
As you might suspect, when the program applies the tracking feature to a flying object, it looks only for the silhouette while a more general "smooth watched scenery" would detect object contours as well. Similarly, simulating an almost-stationary tripod makes your camera motion very static. Note that with Mercalli Expert, you can further customize the parameters. With the Light version, you get the presets only.
After you choose your parameters, you click OK and Mercalli analyzes the footage and displays the box shown in Figure 2, below. If the motion is too strong for the selected parameters, the bar graph to the right of the frame will turn red, indicating either that the footage is beyond repair or that you need to try a different preset. Note the 11 f/s on the bottom of Figure 2, which is a high-definition clip. The typical frame rate on a DV clip was more than 60 frames per second. This was on a Dell Precision 390 with a 3.0 GHz Core 2 Duo dual core processor.
As you can see on the middle left in Figure 1, after rendering, the Compare View pull-down menu in the main interface lets you choose to preview the Final Result, or Horizontal or Vertical split screen in Premiere’s preview window (Figure 3, below). If you display the split-screen view, remember to change it to Final Result before rendering or Mercalli will render that view in your final video.
In testing, Mercalli’s profiles and adjustable parameters along with very fast preview proved to be a recipe for excellent results. I used the same five clips to test Mercalli, SteadyMove (in Premiere Pro), After Effects, and Final Cut Pro’s SmoothCam. All five clips were hand-held shots, including the following:
• parade—Filming my daughter in a parade
• bus—Filming a tour guide on a bouncing bus trip
• band 1—Filming a band at the Fiddler’s Convention from afar
• wedding 1—Bridal 180°
• band 2—Filming a band from close-up in AVCHD
I saved out the BAND 2 AVCHD clip as a QuickTime file for loading into Premiere Pro and After Effects, neither of which support AVCHD. I encountered several issues with Mercalli during my testing. First, it wouldn’t stabilize footage that I had slowed down to 50% speed. I could apply the filter, but I got an error message after the analysis. The workaround was simple: restore the footage to 100%, apply the filter, then slow it back down, which worked fine.
My second issue concerns video edges, which relates back to the technical issue I described previously. The movement of the frame leaves an open space on the side opposite the direction in which the camera is moved. Mercalli offers three options: Dynamic Border, Static Border, and Without Border (Upscaled). The last option is the one used by other programs that automatically zoom in to fill the video edges. The two others create a funky, blurry border around the frame like that shown on the left in Figure 4, below.
When I first saw this, I thought it was a bug in the program, but it’s actually proDAD’s attempt to give you the option to either blur around the border, as you can see on the left in Figure 4, or zoom in and eliminate the border, as shown on the right. Maybe it’s just me, but I can’t imagine any client opting for the blurry view. No biggie; just look for the border when using the program since most presets use the Dynamic Border option.
The Results, Please
In my tests, I rendered the SD clips in DV and the HDV clips in Blu-ray-compatible MPEG-2. I created a conglomerate project in Premiere Pro and loaded the four clips into a single video display to enable easier side-by-side comparisons. You can see the result for the bride shot in Figure 5, below.
Note that for my tests, I didn’t zoom into the corrected After Effects clip. This allowed me to see how much motion was required to adjust each frame, and I could also see the original frame without the softening effect that zooming in produces. That’s why you see the black letterboxes on the bottom and left side of the After Effects clip.
When comparing image stabilization routines, I first look to make sure that the motion is generally smooth and that the images don’t get distorted, which can happen often in high-motion frames where shifting is dramatic. All technologies passed this test. Then I look for disturbing artifacts like strobing or similar motion-related artifacts. All of the tested applications did quite well here as well. Then I try to determine which tool smoothes the most violent motion most effectively. Here, the edge goes to SmoothCam, but Mercalli was only slightly behind and was clearly superior to SteadyMove.
Where Mercalli has the clear edge is in configurability. I liked the ability to "pick my poison," electing to sacrifice smoothness to preserve the edges of the video or to zoom in closely to really clamp down on motion. I also appreciated being able to dial in a certain look. For example, in the Band 1 clip, I wanted the video to look like it had been shot on a tripod since, of course, it wasn’t and should have been. Mercalli gave me the option to make the video look like it had been shot with a locked-down camera, which no other tool did. I can also see where the various presets and configuration options would come in handy for content-specific scenes, such as slow pans, where you want to eliminate the up and down motion but not the pan itself.
The bottom line for Windows users is that Mercalli produced results that were clearly preferable to SteadyMove, and it proved much more usable than After Effects for image stabilization. So even if you have both of these options at your disposal, Mercalli is well worth a look, especially since it only costs $119. Better yet, you can try it before buying.
Jan OzerEventDV and Streaming Media. (jan at doceo.com) is a contributing editor to