Hi,

We can use several types of widgets using odoo
abc.js:

openerp.web_sample_widget = function(instance,local) {
    var _t = instance.web._t,
    _lt = instance.web._lt;
    var QWeb = instance.web.qweb;
    console.log("sample widget head"); //It prints fine

    local.WidgetName = instance.Widget.extend({
        start: function() {
            console.log("sample widget"); // this not print
        }
    });

    instance.web.client_actions.add(
      'sample.widget', 'instance.web_sample_widget.WidgetName');
}

XML: 

<odoo>
    <data>
    <template id="assets_backend" name="web_graph assets" inherit_id="web.assets_backend">
        <xpath expr="." position="inside">
            <script type="text/javascript" src="/web_sample_widget/static/src/js/abc.js"></script>
        </xpath>
    </template>
  </data>
</odoo>

For creating video widgets you can refer to the blog: https://www.cybrosys.com/blog/how-to-create-widget-odoo#:~:text=There%20are%20so%20many%20widgets,create%20widgets%20preview%20using%20JS.

Hope it helps