Add videos in place of product images by adding the YouTube or Vimeo URL to the product image ALT text.
1. Go to the Products tab in the Shopify Admin Dashboard and select the product to modify
2. Hover over the image you would like to turn into a video and click the ALT link
3. Paste your video URL into the Image alt text input (video player only supports Youtube and Vimeo videos)
For more details, check out Setting up Empire's product page