           {% set file = file_to_data_uri(slide_config.file) %}
            {% else %}
              {% set file = assets_dir / (prefix(outer_loop.index0) + slide_config.file.name) %}
            {% endif %}
        <section
          data-background-size={{ background_size }}
          data-background-color="{{ presentation_config.background_color }}"
          data-background-video="{{ file }}"
          {% if loop.index == 1 and outer_loop.index == 1 %}
          data-background-video-muted
          {% 