Tracking isn’t something every editor does on a regular basis, but when you need it, very few NLEs have built-in tracking tools. This is definitely true with Apple Final Cut Pro X. CoreMelt makes some nice effects plug-ins, but in addition, they’ve produced a number of workflow tools that enhance the capabilities of Final Cut Pro X. These include Lock & Load X (stabilization) and SliceX (masking). The newest tool in the group is TrackX and like SliceX, it uses Mocha tracking technology licensed from Imagineer Systems. In keeping with the simplified controls common to FCP X effects, the tracking controls in TrackX are very easy to apply and use.
TrackX installs as three generators within FCP X – Simple Tracker, Track Layer and Track Text. All use the same planar-based Mocha tracker. The easiest to use – and where I get the best results – is the Simple Tracker. This lets you attach text or objects to a tracked item, so they travel with its movement.
The example used in their tutorial is of a downhill skier. As he races downhill, a timer read-out travels next to him. This works well and displays well, because the tracked objects do not have to perfectly adhere to each other. It uses a two-step process. First, create the item you want to attach and place it into a compound clip. Therefore, it can be a complex graphic and not just text. The second step is to track the object you want to follow. Apply the TrackX generator and trim to length, use the rectangle tool to select an area to be tracked, drop the compound clip into the filter control pane’s image well and then track forward or backwards. If there are hiccups within the tracks, you can manually delete or insert keyframes. Like other trackers, you can select the mode of analysis to be used, such as whether to follow position, scale or perspective.
The second TrackX generator is Track Layer. This worked well enough, but not nearly as well as the more advanced versions of Mocha that come with After Effects or are sold separately. This tool is designed to replace objects, such as inserting a screen image into a TV, window, iPad or iPhone. To use it, first highlight the area that will be replaced, by using the polygon drawing tool. Next, add the image to be used as the new surface. Then track. There are controls to adjust the scale and offset of the new surface image within its area.
In actual practice, I found it hard to get a track that wasn’t sloppy. It seems to track best when the camera is panning on an object without zooming or having any handheld rotation around the object. Since Mocha tracking is based on identifying flat planes, any three-dimensional motion around an object that results in a perspective change becomes hard to track. This is tough no matter what, but in my experience the standard Mocha trackers do a somewhat better job than TrackX did. A nice feature is a built-in masking tool, so that if your replacement surface is supposed to travel behind an object, like a telephone pole, you can mask the occluded area for realistic results.
Lastly, there’s Track Text. This generator has a built-in text editor and is intended to track objects in perspective. The example used in their demos is text, that’s attached to building rooftops in an aerial. The text is adjusted in perspective to be on the same plane as the roofs.
Overall, I liked the tools, but for serious compositing and effects, I would never turn to FCP X anyway. I would do that sort of work in After Effects. (TrackX does not install into Motion.) Nevertheless, for basic tracking, TrackX really fills a nice hole in FCP X’s power and is a tool that every FCP X editor will want at their fingertips.
For new features announced at NAB and coming soon, check out this video and post from FCP.co.
©2014 Oliver Peters
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