web/_includes/embed/video.html

{% assign video_url = include.src %}
{% assign poster_url = include.poster %}

{% unless video_url contains '://' %}
  {%- capture video_url -%}
    {% include img-url.html src=video_url img_path=page.img_path %}
  {%- endcapture -%}
{% endunless %}

{% if poster_url %}
  {% unless poster_url contains '://' %}
    {%- capture poster_url -%}
      {% include img-url.html src=poster_url img_path=page.img_path %}
    {%- endcapture -%}
  {% endunless %}
  {% assign poster = 'poster="' | append: poster_url | append: '"' %}
{% endif %}

{% assign attributes = 'controls' %}

{% if include.autoplay %}
  {% assign attributes = attributes | append: ' ' | append: 'autoplay' %}
{% endif %}

{% if include.loop %}
  {% assign attributes = attributes | append: ' ' | append: 'loop' %}
{% endif %}

{% if include.muted %}
  {% assign attributes = attributes | append: ' ' | append: 'muted' %}
{% endif %}

<p>
  <video class="embed-video file" src="{{ video_url }}" {{ poster }} {{ attributes }}>
    Your browser doesn't support HTML video. Here is a <a href="{{ video_url }}">link to the video</a> instead.
  </video>
  <em>{{ include.title }}</em>
</p>