How to make a keyframe that count the time from the end of clip?

Hello, let me start with an example:

The red keyframe is at “3 seconds after the clip start”, but I want it to be at “2 seconds before the clip end”.

The reason I want to do this is, when I copy the filter to another clip which is longer than this one, I will have to adjust the keyframe time. For example, I copy the filter from White clip which is 5 seconds long, and paste it to Green clip which is 6 seconds long:

I want the red keyframe at “00:00:04:00” when I paste this filter.

You can’t do it with Advanced Keyframes because they are all relative to the beginning of the filter. But you can do it with Simple Keyframes because the “End” keyframe is relative to the end of the filter.

Thank you for your reply and even wrote a document about Simple Keyframes!

But Simple Keyframes can only set 2 keyframes, which is not enough for what I want to do; I suggest add an option in Advanced Keyframes to let any keyframe can choose to be relative to the begging or the end of the filter.