Cropping is used to reduce the visible picture area by changing the output dimensions, width and height in pixels, and the X, Y values. An example of cropping and the crop menu is seen in figure 2.17. The easiest way to use cropping is to click with the LMB at the spot to begin cropping and while holding down the LMB, drag the mouse. This creates a rectangular cropping area. To change the size/location of that area, click on any of the 4 corner points with the LMB and drag. While dragging, you will see the X1, Y1 coordinates and W for width, H for height, in the Crop tool popup menu automatically change numerical value to reflect the current position. For precise locations, you can keyin exact values into those textboxes instead of using the mouse. Once you have the crop area defined as you want it, then click on the Apply button to have the actual cropping take affect.

There are 3 choices of crop methods to choose in the menu pulldown on the bottom right side.

  1. Reformat - Reformat Session crops and changes the Format for the entire session. Because the Format is changed, this is applied to all tracks in the project. The part of the image outside the rectangle will be cut off and the projector will make the video fit. The Settings Format window will show the new project Width and Height values and the projector tool window will show the new X, Y values. Track size remains unchanged. You can undo the cropping by entering the original project dimensions in the Settings Format window for the Width and Height. You will also have to use the Projector tool in the Compositor toolbar to Ajdust projector automation by clicking on the Reset icon.
  2. Resize - Resize Projector; to undo this, enable Adjust projector automation and do a Reset.
  3. Shrink - Resize Projector and Camera; to undo this, enable each of the Adjust projector and camera automation tools, one at a time, and do a Reset in the menus.
An important note here is that the original aspect ratio will be maintained so if your frame is rectangular (as many are) and you "crop" by surrounding the region of interest with a square, the cropped area will be more than you marked in order to keep the aspect rectangular shape. The Resize and Shrink options are applicable to all video tracks except the disarmed ones. This is in contrast to the Reformat option, as mentioned previously, which applies to all tracks even if disarmed because it changes the Format for the session. One last note of interest, this cropping is keyframable.

Figure 2.17: Crop menu and outlined crop rectangle on the right side
Image cropped_area

An easy to follow step by step usage of the cropping tool is outlined next.

The CINELERRA-GG Community, 2021