The Ella theme supports the use of background fullscreen video clips imported from youtube. This section found underneath the splash page settings area, controls this feature. This feature is available in page builder pages only. The video background if enabled, will have a fixed position, which means that it will remain in the background irrespective of how the page's content scrolls. If some sections in the page have a transparent background, this can give rise to some interesting visual effects. The settings available in this feature are as follows:

Use YouTube Video | Enable/Disable the background Youtube video feature. | |
YouTube Videos | Here You insert the link to the Youtube video(s) you wish to play in the background. Multiple videos can be inserted using this control, in which case when one video finishes, the next one will begin. If only one video is inserted, this video will automatically loop. | |
Fallback Image | Auto-play background video is not supported by many mobile devices/operating systems. In these cases a fallback image is required to be used. Insert here the image you wish to show in these devices. This would normally be a screen capture from the video clip. |
Once this feature has been enabled, any sections in the same page which use the "Default" setting for background, will become transparent. This means that that section's content will be viewed with a video in the background. To remove the effect, simply set a background color for that section explicitly. The footer section's background automatically becomes transparent.
To set a video background splash area:
Create an empty slide item using the "Slides" custom post type in the main WP admin menu.
Create a transparent Slider View, using the "Views" custom post type in the main WP menu.
In this slider view, set the input data as "Slides" and insert only the empty slide created above.
Set the output as "Slider - Vario" and name the slider something like "Transparent Slider" and publish the view.
No in the page where you wish to use the video bg, in the splash settings below the page builder, set the splash to Yes, select the Transparent Slider as the "Slider" for this splash section.
Now, provided you have inserted a video into the background video settings box, located just beneath the splash settings box, then the background video should now be displaying.