If you see a "Live Caption" box that appears underneath the video in a black box, that is a browser thing, not a Joomlart thing.
Could you share screenshot and URL where I can see the video? as I don't see it on your site now.
A video, at least, if the browser is set to display underneath the video window, will take voice and show print. Nothing wrong with Blockk.
richnyc30 Let me know if you need other help then 🙂