is there any code that, when clicking a button, makes the video speed up 0.5x, 1x, 1.5x, 2x?
I can’t find any API which could do what you want.
https://www.wix.com/velo/reference/$w/videoplayer
If you use an iframe (instead of Wix video player) to show the video, you can adjust this code and change the speed as you wish:
http://jsfiddle.net/jpreynat/e11oy0eu/
(P.S. for YouTube videos)
I really wanted to by the code VELO, but I believe it is not possible by the wix API
function onPlayerReady(event) {
player.setPlaybackRate(0);
event.target.playVideo();
}