See aslo:
Damping camera jerks
One often needs to smooth out object's motion by eliminating tremor caused by shaking of a hand-held camera. PatchMaker has a built-in function for stabilizing the selected object by freezing it in the given position. The total object stability, however, may not be desirable in all cases. Here is an example:
The colored star moves from the left to the right frame edge. If it is stabilized, the major part of the source image will disappear simply because the star moves:
It can be seen that more than a half of the frame area is "lost" in total object stabilization:
See also :
"What should I do to reduce jerking and yet avoid informative region loss?", you may ask. There is a solution, and it consists in exploiting the cooperation between PatchMaker and AE to the full. In a few words, we need to eliminate only high-frequency components of the motion while preserving its low-frequency components. Let us examine in detail the steps to be taken:
-
First, perform full object stabilizing in PatchMaker. It does not matter if, at some point, the stabilized object gets almost completely out of the frame boundaries.
See also :
-
Transfer the whole project by any available method from PatchMaker to AE. A new AE composition, named after your PatchMaker project, will be created. After it is opened in the Timeline window, you can perform common operations such as: turning off the overlay [A], if you don't need it, and switching the quality setting from Draft Quality to Best Quality[B]:
-
Create a new composition that includes the given one by dropping the name of the existing composition in the Project window onto the Create a new Composition icon:
See also:
-
Open the new composition in the Timeline window and select the nested composition layer. Switch back to PatchMaker and set the Task property of the composition to Motion Tracking. This time export the transformations alone by choosing After Effects|Export Transformations or by using the After Effects® panel. You will get back to AE automatically when the export is completed.
-
If the transformations are transferred to AE without quality loss, the compositing results will match the source footage exactly. This is because the stabilizing transformations are applied by the nested composition and their inverse by the overall composition. The frame margins will be lost in the above sense because the transformations are applied in two steps, giving rise to black fields around the star. To get exactly the same sequence as the source footage, toggle the Collapse Transformations button for layer [A]. As a result, only one combined transformation (identity, in our case) will be applied to the layer, and the black fields will disappear.
-
Select the motion parameter properties of the layer where you wish to retain the low-frequency motion component. Add an expression to these properties through the menu ( Alt+Shift+= key). By using the expression language menu button or by typing, enter the smooth function in the expression field: smooth(width=.2, samples = 50, t = time).
Adjusting the width parameter of this function, you can get the desired damping of the high-frequency motion component, preserving at the same time, for example, a smooth panning. When this value is close to zero, no damping occurs and the result will be close to the source footage. With very large values, all motion components are damped.
A correct width value is easy to determine by examining graphs of the original and smoothed property values. To do that, press the Show Post-Expression Graph button in AE. The original (black) and smoothed (red) values will look something like this:
That solves the task. Congratulations!
