This effect can be used to mask peoples faces. It uses motion estimation to track subjects and mask faces. It is the MLT filter autotrack_rectangle
See video below on how to use this effect. Warning: The effect is not 100% reliable.
The Auto Mask effect can also be used to track motion of an object and use it later as keyframes for an effect / transition.
|The method described here is a re-purposing of the motion tracking data that the Auto Mask effect calculates. You do not need to follow the method described below to generate an Auto Mask that will obscure faces. The instructions in the above video should be enough. Nor can you use the method describe below to improve the tracking of the mask created by the Auto Mask effect.|
To use this feature, first add the clip you want to analyse in timeline, and add the "Auto Mask" effect to it - Figure 1.
Then click on the
Checking the Limit keyframes number checkbox In the "Import Keyframes" dialog (Figure 4) will cause Kdenlive to only import every nth frame (where n is the number selected in the combo box). This is a useful feature if you want to manually edit the keyframes that are imported because it allows you limit the number of key frames you will need to manually edit. If this check box is not checked then you import a key frame for every frame that is in the source clip.
The motion tracking data is saved with the clip properties. You can view this data from the clip properties Analysis tab - Figure 5. Delete the data using button 1