oliverdavies.uk/source/_includes/talk/video.html.twig

{% if page.youtube.id or page.vimeo.id %}
    <div class="mt-4">
        <h2>Video</h2>

        <div class="talk-video">
            {% if page.youtube.id %}
                <iframe
                    width="678"
                    height="408"
                    src="//www.youtube.com/embed/{{ page.youtube.id }}"
                    frameborder="0"
                    allowfullscreen
                >
                </iframe>
            {% elseif page.vimeo.id %}
                <iframe
                    src="https://player.vimeo.com/video/{{ page.vimeo.id }}"
                    width="640"
                    height="360"
                    frameborder="0"
                    webkitallowfullscreen
                    mozallowfullscreen
                    allowfullscreen
                >
                </iframe>
            {% endif %}
        </div>
    </div>
{% endif %}