Create a page using just a video. Then append ?tmpl=component to that URL. It should display just the article. Use that URL to create a menu item that opens in a popup.
If you need to hide more elements from the article page, you may need to use some CSS specific to that page or create a sub-template/override for com_content. If you used K2 for your content, the process would be easier...
Fotis / JoomlaWorks Support Team
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