anyone knows wich program should i use if i want to retouch video, like make
waists smallers or disappear imperfections from face shots?

To do what your trying to do would require something like Adobe After Effects Professional.

thanks, im thinking if i should buy that program

Neat Video will get rid of grain really well.
After effects will do some retouching, but the definitive is rotoscoping, which is how they do the light saber...yes....frame by frame.

frame by frame
mmm... too much work lol i have after effects in my other pc but i dont really know how
to use it...

although after effects is like the "photoshop for video" unless the subject is standing in the exact same place the entire video you will have to make adjustments frame by frame, keyframing helps, but if you end up keyframing every other frame you aren't cutting your workflow down any.

You're looking at compositing software. After Effects has gotten better and is used
but industry standards for film are more like Shake, Combustion, Digital Fusion, Nuke,
etc or the hardware packages like Flint, Flame, Inferno, etc

The difference being most of these are node based compositing rather than layers
like After Effects.

although after effects is like the "photoshop for video" unless the subject is standing in the exact same place the entire video you will have to make adjustments frame by frame, keyframing helps, but if you end up keyframing every other frame you aren't cutting your workflow down any.

Frame by frame usually looks WORSE than keyframing. The object with rotoscoping is
to make as little keyframes as possible to make the motion-tracking smooth.

This is all wrong - After effects has something called Motion Tracking, it will analyze each frame based on checkpoints. So it can map any animation and distortions to these points, or relative to them

As does all compositing software. After Effects was one of the last to implement it.
The tracking can be used to stabilize a hand held shot also. You can choose between one
tracking point, 2, or 4. Motion tracking adds a keyframe every frame. Depending
on what you're tracking, this can be improved.

ooh now i get it.. thanks to all... does anyone knows where can i find some tutorials?

Lynda.com maybe