Copies frame from video in current tab, check that only one video object is present. Click on the button and open the copied URL in new tab.

jstricks_copy_video_frame.js

// based on https://stackoverflow.com/questions/13760805/how-to-take-a-snapshot-of-html5-javascript-based-video-player

var canvas = document.createElement('canvas');
canvas.width = 1920;
canvas.height = 1080;
var ctx = canvas.getContext('2d');

ctx.drawImage(document.getElementsByTagName("video")[0], 0, 0, canvas.width, canvas.height);
var dataURI = canvas.toDataURL('image/jpeg'); // can also use 'image/png'

var b = document.createElement("button");
b.onclick = () => {navigator.clipboard.writeText(dataURI)};
b.style = 'z-index:999999;position: fixed;top: 5px;';
document.appendChild(b);