Method 1 (simple, but there are certain requirements for the previous materials): If the materials to be excavated do not contain white, the method of using color keys can be easily removed.

First, in the Effects panel, find the video effect-Keying-Color key.

Secondly, drag it to the material that needs matting on the timeline.

Third, in the "Effect Control" panel, change the "main color" to white (or directly select it on the video with a straw).

4. Before the main color turns white:

5. After the main color changes to white:

Six, slightly adjust the color tolerance, white completely disappear:

Seven: slightly adjust the value of feathering edge to make it more suitable for the background added after the following situations:

Eight: Add a new background and finish.

Method 2 (troublesome, no requirement for preliminary materials):

1. Select the Set Mask button in the Effects panel.

2. After dragging it onto the material to be keyed, select the pen tool in the Effect Control panel.

Tick off the outline of the part to be deleted in the preview window (if there are multiple outlines, add a mask: click the pen again and draw with the second mask).

Third, set the "Use for Mask" and "Reverse Mask" buttons in the mask.

Fourth, the effect

5. If it is a dynamic video, click the "Play" button in the mask to automatically track the drawing area.

(However, because the machine is manual again, some frames may not be tracked in place and need to be supplemented manually. )

Six, add background, feather numerical modification, etc. In the same way.

In addition: AE's Roto brush will be more convenient.