Cropping Black Edges

You can crop black edges (or any color you choose) from your footage to eliminate unnecessary computation:

1.

Select Image > CurveTool to insert a CurveTool node after the image sequence you want to analyze.

2.

Make sure a Viewer is connected to the CurveTool node.

3.

In the CurveTool controls, select AutoCrop from the Curve Type dropdown menu.

4.

Using the color parameters, select the color you want to track.

5.

To control how far the color can deviate from the selected color and still be cropped off, use the Intensity Range slider.

6.

From the channels dropdown menu and checkboxes, select the channels you want to analyze.

7.

If you want to analyze an area in the frames rather than entire frames, define a region of interest either by dragging the edges of the frames to a new position in the Viewer, or by defining the area using parameters labeled ROI.

8.

Click Go! to analyze the frames. This opens the Frames to Execute dialog.

9.

In the dialog, define the frames to analyze. Enter the first frame, followed by a comma and the last frame. Click OK. Nuke starts analyzing the frame sequence.

10.

You’ll find the results of the analysis on the AutoCropData tab where the parameter values have turned blue to indicate they are animated over time. To see the animation curve, right-click on a parameter field and select Curve editor.

Once Nuke has created the animation curve, you can copy the animation or any of its values into a Crop node, for example, to match the analyzed crop area there. Ctrl/Cmd+click on the animation button and drag and drop it to another parameter to create an expression linking the two.