… for Apple Final Cut Pro X
Tip #1387: Calculating Clip Positions
Larry Jordan – LarryJordan.com
Final Cut simplified how clips are positioned, making effects easier to calculate.
I discovered this tip while researching a recent PowerUP webinar introducing Apple Motion 5.5.
All NLEs determine position using pixel coordinates. Where those coordinates start is called the 0,0 position.
Final Cut sets the 0,0 position at the exact center of a project. The significant benefit to this approach is that you can instantly center a clip, regardless of its size, by entering 0,0 in Video Inspector > Transform > Position.
NOTE: Adobe Photoshop and Premiere Pro determine clip positions in a sequence from its upper left corner.
By defining the center as 0,0, the position of the center doesn’t change even when the project size changes. Final Cut’s approach also makes the math of moving clips much easier, because when you move a clip, you are moving it from it’s center, not the upper left corner.
For example, when creating a “quad split” image (see screen shot), where each image is scaled 50%, the center of each frame moves by the same amount, but in different directions:
- Top left: -320, 180
- Top right: 320, 180
- Bottom left: -320, -180
- Bottom right: 320, -180
The only difference is the sign (positive or negative), the pixel values are all the same.
NOTE: This positioning scheme also means that if something is off-center, it is easy to center simply by entering 0,0 as the position coordinates.