Mask working slow in after effect

[Prajwal5EFB]

My video is about 4-5 seconds and i masked my hand in that video to give some effects and when i masked my hand from 3rd second to 5th second in which i was moving my hand from left to right, my 3rd second mask automatically changed its place. This mask is too slow to change its position and when i saw a youtuber video his mask changes its position faster. What should i do to make my mask work properly 

[Guest]

Moving thread to the After Effects forum from Using the Community

[Mylenium]

Impossible to know and your description doesn't realyl make a lot of sense. Ae isn't arbitrarily making stuff misbehave. You need to provide much better info, beginning with basic system info at least, screenshots of the situation, proper explanations of what you are actually doing.

Mylenium

[Rick Gerard]

What you are doing is called Rotoscope. If the movement between keyframes does not match up then you need more keyframes. The usual workflow is to start by setting keyframes when motion changed direction then go back in between those keyframes and make more adjustments. The more random the speed changes are, the more keyframes you'll need. If the motion is just a smooth acceleration you can sometimes solve the problem by using the graph editor, but that requires a lot of experience and practice to be efficient. Here's a very quick and simple tutorial I did a long time ago that demonstrates the technique.

Scott Squires is a master of the technique. Take a look at his Effects Corner: Rotoscoping - Part 1 for the history, theory, and basic workflow. When you finish that look at Effects Corner: Rotoscoping - Part 2 for the actual technique used to create and animate the mask paths or splines. He does not use After Effects, but the workflow is exactly the same. Use as few keyframes as you can and use many different paths (splines) as you need to make the work efficient.