how to stream video on-site generated from link preview in a text area?
Opengraph Filter module provides this: template_preprocess_opengraph_filter()

You can implements it in your custom module or theme for reading the video url. Then you can use the video url to output the player.

function mytheme_preprocess_opengraph_filter(&amp;$variables) {
  $key = 'video';
  if (isset($variables['metatags']['og'][$key])) {
    $video_url = $variables['metatags']['og'][$key];

    // more code to operate $video_url.
    // dpm($video_url);
  }
}


You can start with it. It would be a long story if you want to load the video after clicking the thumbnails. I would suggest you to split the question into multiple specific questions for different step. It is more easy for other to provide answer and also for those who is looking for answer. Thanks.