DITA: Video
To embed video, you must use object tags.
Here's a sample
embed:
<object width="640" height="360" data="//www.youtube.com/embed/vwh93zo7_oU?rel=0">
<param name="src" value="//www.youtube.com/embed/vwh93zo7_oU?rel=0"/>
<param name="movie" value="//www.youtube.com/embed/vwh93zo7_oU?rel=0"/>
<param name="allowFullScreen" value="true"/>
<param name="allowscriptaccess" value="always"/>
</object>
You can't use HTML5 video tags.