Woocommerce - insert video into product gallery slider

I am trying to insert an embedded video (youtube) into the product gallery slider that appears on the product page.

So far I am working with

add_filter('woocommerce_single_product_image_thumbnail_html','my function');

      

        
        
        
      

    

to add a thumb video, but I don't know what filters to add new content to the div-woocommerce-product-gallery (where the big images are) or the lightbox.

Also, the woocommerce_single_product_image_thumbnail_html hook fires after every thumb, so it would be nice if I use a filter that fires before / after the thumbs are displayed. I am trying to use

add_action( 'woocommerce_product_thumbnails', 'my_function', 20 );

      

        
        
        
      

    

but that won't work.

So the question is, what hooks do I need to use to add new thumbs and new slides to the woocommerce product slider. Thank.