The d4p_video element is for including video in a DITA topic. It corresponds to HTML5's <video> element. While it is possible an editing environment could display video, it is more likely that video won't actually be rendered and playable until a DITA source is transformed into an output deliverable, such as HTML files or an epub3 package. Height and width can be specified as optional attributes. A video's source should be indicated by a child <d4p_media_source> element (more than one source may be specified). A poster image (at most only one) can be specified as a child <d4p_video_poster> element. It is good practice to include a child <desc> element as alternate content for deliverable formats that cannot play video or for accessibility purposes for a user who is visually impaired. For example, a <desc> element might describe what the video shows or give directions for accessing the video in another manner.