<script async custom-element="amp-youtube" src="https://cdn.ampproject.org/v0/amp-youtube-0.1.js"></script>
<amp-youtube data-videoid="dQw4w9WgXcQ" layout="responsive" width="480" height="270"></amp-youtube>
<script async custom-element="amp-iframe" src="https://cdn.ampproject.org/v0/amp-iframe-0.1.js"></script>
<amp-iframe src="https://example.com/embed" width="600" height="400" layout="responsive" sandbox="allow-scripts allow-same-origin">
<div placeholder>Carregando...</div>
</amp-iframe>
Respeite as regras de sandbox e garanta que o conteúdo embutido esteja em HTTPS. Use placeholder e layout="responsive" para uma boa UX.