How to perform jquery script only once?

I use the isInViewport script to play the video on scroll, but it doesn't look very good because it happens multiple times. Please tell how to limit the triggering of animation or video playback to literally once. Tried to add with one() and true/false but the code didn't work (I still green in jquery).

<div class="block"><span>Video below</span></div>

<div class="block video-block">
  <video class="video" loop="loop" width="640" controls="controls" muted>
      <source src="http://denis-creative.com/wp-content/uploads/2018/01/video.mp4" type="video/mp4" /> 
      <source src="http://denis-creative.com/wp-content/uploads/2018/01/video.ogv" type="video/ogv" /> 
      <source src="http://denis-creative.com/wp-content/uploads/2018/01/video.webm" type="video/webm" /> 
    </video>
</div>

<div class="block"><span>Video above</span></div>

.block{
  height: 100vh;
  font-size: 60px;
  text-align: center;
  display: flex;
}
.block > *{
  margin: auto;
  display: inline-block;
  max-width: 100%;
}

// Plugin isInViewport
!function(e,n){"object"==typeof exports&&"undefined"!=typeof module?n(require("jquery"),require("window")):"function"==typeof define&&define.amd?define("isInViewport",["jquery","window"],n):n(e.$,e.window)}(this,function(e,n){"use strict";function t(n){var t=this;if(1===arguments.length&&"function"==typeof n&&(n=[n]),!(n instanceof Array))throw new SyntaxError("isInViewport: Argument(s) passed to .do/.run should be a function or an array of functions");return n.forEach(function(n){"function"!=typeof n?(console.warn("isInViewport: Argument(s) passed to .do/.run should be a function or an array of functions"),console.warn("isInViewport: Ignoring non-function values in array and moving on")):[].slice.call(t).forEach(function(t){return n.call(e(t))})}),this}function o(n){var t=e("<div></div>").css({width:"100%"});n.append(t);var o=n.width()-t.width();return t.remove(),o}function r(t,i){var a=t.getBoundingClientRect(),u=a.top,c=a.bottom,f=a.left,l=a.right,d=e.extend({tolerance:0,viewport:n},i),s=!1,p=d.viewport.jquery?d.viewport:e(d.viewport);p.length||(console.warn("isInViewport: The viewport selector you have provided matches no element on page."),console.warn("isInViewport: Defaulting to viewport as window"),p=e(n));var w=p.height(),h=p.width(),v=p[0].toString();if(p[0]!==n&&"[object Window]"!==v&&"[object DOMWindow]"!==v){var g=p[0].getBoundingClientRect();u-=g.top,c-=g.top,f-=g.left,l-=g.left,r.scrollBarWidth=r.scrollBarWidth||o(p),h-=r.scrollBarWidth}return d.tolerance=~~Math.round(parseFloat(d.tolerance)),d.tolerance<0&&(d.tolerance=w+d.tolerance),l<=0||f>=h?s:s=d.tolerance?u<=d.tolerance&&c>=d.tolerance:c>0&&u<=w}function i(n){if(n){var t=n.split(",");return 1===t.length&&isNaN(t[0])&&(t[1]=t[0],t[0]=void 0),{tolerance:t[0]?t[0].trim():void 0,viewport:t[1]?e(t[1].trim()):void 0}}return{}}e="default"in e?e.default:e,n="default"in n?n.default:n,/**
 * @author  Mudit Ameta
 * @license https://github.com/zeusdeux/isInViewport/blob/master/license.md MIT
 */
e.extend(e.expr[":"],{"in-viewport":e.expr.createPseudo?e.expr.createPseudo(function(e){return function(n){return r(n,i(e))}}):function(e,n,t){return r(e,i(t[3]))}}),e.fn.isInViewport=function(e){return this.filter(function(n,t){return r(t,e)})},e.fn.run=t});
//# isInViewport

// Play Video
$(function() {
  var $video = $('.video');
  var $window = $(window);

  $window.scroll(function() {
    if ($video.is(":in-viewport")) {
      $video[0].play();
    } else {
      $video[0].pause();
    }
  });
});

You could add a var to check if the video is still playing (for example is_playing) and check it with an inner if:

$(function() {
  var $video = $('.video');
  var $window = $(window);
  var is_playing = false;

  $window.scroll(function() {
    if ($video.is(":in-viewport")) {
      if (!is_playing) {
        is_playing = true;
        $video[0].play();
      }
    } else {
      $video[0].pause();
    }
  });
});