Final Cut Motion Tracking Plugins
   

Pin

 

Lyric's Pin filter is a compositing filter that lets you track a feature moving within a clip and then pin another, usually masked, clip to it so that the pinned clip moves along with the feature.

You can use Pin to composite new moving features onto an existing clip, remove features in a clip by pinning a cloned area from elsewhere in the clip, generate traveling mattes for other clips, and so on.

It provides several features, including:

  • sub-pixel and center-of-weight motion tracking
  • feature selection on any clip frame
  • interactive, frame-by-frame tracking repair
  • track smoothing
  • pinned clip controls, including
    • offset
    • scale
    • rotation
    • opacity
    • edge-softening
  • final output can be composite, pinned clip only, or pinned clip traveling matte

Pin has a set of fixed steps you work through to get the final composited image. You select the step you wish to perform in the Step dropdown menu. The steps are:

  1. Select the feature to track and set the tracking options
  2. Start the motion track process
  3. When the tracking finishes, check it and optionally repair any tracking errors, including retracking portions of the clip
  4. Select the clip to pin, set pinning parameters and pin the clip based on the final track

Doing things this way lets Pin build a record of an entire motion track, so that it can support features like manual track correction, track smoothing and image preprocessing.

The first 3 steps are identical in all the Lyric Tracking Plugins and are described in Tracking an Image Feature.

 

When you have created a satisfactory image motion track, select 4. Pin in the Step dropdown menu to complete the pinning. Note that you can go back to the first 3 steps at any time to repair a track or track an alternative feature.

Drag a clip or image to pin onto the clip well in the Clip to Pin parameter. It will appear, centered over the feature and will move with the feature as you move the playhead through the clip. Generally, you would pin clips with alpha channels, so that they composite over the clip being tracked.

You can use the other parameters in the Pin section to adjust the pinned clip, setting its scale, orientation, opacity and edge softness as desired. A very useful parameter is the Clip Offset point control. It allows you to offset the pinned clip from the exact center of the feature and the pinned clip will then follow the feature at this offset in all other frames. This is handy if you have a good feature for tracking purposes but it is not exactly at the point over which you wish to place the pinned clip. See the examples below for details.

Note that offset, scaling & rotation are relative to the pinned clip's original center, so you might want to adjust this prior to pinning to allow the orientation adjustments you might need. In general, it is best to prepare clips-to-be-pinned such that they are roughly the right size, particularly those from Final Cut generators, to avoid large amounts of scaling within the Pin filter.

Smooth Track applies a smoothing filter to help reduce jerkiness in the track. You can see the smoothed version of the track with the Show Track option enabled.

 

The following example shows the "5" sign being tracked and a sign made with the Outlined Text generator being pinned and offset to the left.

The sign to be pinned was created with the Final Cut Outlined Text generator.
Steps 1, 2 & 3 generated a track for the"5" sign.
When first pinned, the sign is full size and centered over the tracked feature.
The sign has been offset, using the Clip Offset point control, then scaled, rotated slightly and made slightly transparent, using the Pin section parameters shown at left.
  In the next example, the "5" motion track is used to pin a clone of the same clip over the "5" sign to remove it from the clip.
A freeze-frame copy of the original clip is cropped to get a portion of the fence to the left of the "5" sign. This becomes the clip being pinned. The clone is pinned over the "5" sign and its position adjusted with Clip Offset to exactly match the background fence mesh. The edge has been softened with Edge Soften to make it blend better with the background. It will follow the track, staying pinned over the "5" sign as the camera moves about.
  The Show dropdown menu lets you chose how the pinned clip will be shown in the output. Composite places the pinned clip over the clip being tracked. Clip Only hides the clip being tracked and just shows the pinned clip. Clip Mask hides both and outputs the pinned clip's alpha channel, so that it can be used as a traveling matte with the Travel Matte - Alpha Composite Mode in the Final Cut timeline.
 

You should render the composited clip while still working in the Filter tab to ensure that the recorded track is not lost. See the note here about when Final Cut will reset the track and how to protect your track and renderings.

Note also that final renderings in the Pin step will not contain any of the track displays that might be visible in the canvas.

 

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