Are you talking about a sprite animation? Video is a different object.
You can duplicate the animation frames in reverse order, and then loop the animation:
0 1 2 3 4 5 4 3 2 1
If the animation is long and you don't want to increase the number of images in the project, you can set animation frame with events. For example, run a value tween from 0.5 to (Sprite.AnimationFrameCount-0.5), ping pong=yes, looping=yes.
And set Sprite animation frame to Self.Tween.value("tag")