Best answer by Mathis
That's a good question - thanks for posting on our help forum. Whether or not you can use our embedded player on a website depends on the html compatibility of the hosting website (eBay). Hmm, I've researched this, and it looks like they do not allow for HTML5 content to be part of your item subscriptions.
Thus, in order to weigh your options about this, I'd recommend to get in touch with eBay direclty - I'm sure they have a legitimate reason for not allowing specific elements as part of the item description, but who knows - maybe yours is a good feature request for them.
Hope this helps!