This is what you need to do you want to render the video field provided by the video_embed_field module in a block or somewhere in your theme.

// get the node somehow
$node = node_load(2953); // use any logic that works for you
// then get the url and turn it into an embed code like so
  if (!empty($node->field_video_url)) {
    $help_modal['video'] = array(
      '#markup' => theme('video_embed_field_embed_code', array('url' => $node->field_video_url[LANGUAGE_NONE][0]['video_url']))

then in your block’s tpl.php file just print it out like this

<?php print render($help_modal['video']); ?>

The video_embed_field module is great and simple to use, I definitely recommend it.