I recently pushed out a change that will use the iframe style embedding for YouTube videos. So it should use the HTML5 video if you have opted into YouTube's HTML5 trial.

This section assumes you are using a web form builder for creating web forms and have an embed code that will be used to insert the form into your webpage. Before you can embed a video, you need to ...

To embed a Vimeo video onto another webpage, you'll need to copy and paste the video's unique embed code.