The default header for posts uses the featured image. You may customize the header of individual posts to display a video background.
Fallback Image
Be sure to create a fallback still image for the video.
Add a still fallback image to the media library for the video. From the Media menu in left toolbar, select Add Media File.

Click on Select Files (or drag and drop file onto targeted area.)

Get the id of the fallback still image. Click on Media > Library. Select the image.

Copy the ID.

Add Video to Media Library
Add remote video, under Media > Add Multimedia.

Insert the url for the remotely hosted video, and create a title for it. Click the Save button.
Example: https://vimeo.com/1024499547?autoplay=1&loop=1&muted=1

Click on Media > Library. Select newly added video.

Use that fallback image’s id as the Media Poster (image id) for the remote video.

Setup Banner Video on a Post
Edit the post on the backend. Add the fallback image as the Featured Image.
Scroll down to bottom Page Options. Select Header on the left side. Then under Header Type, select Default.

Set Minimal Height to 600.

Scroll down to Background. Click on the +

Select the video from the Media library. Click on Insert to Options button.

Under Background Size, select Cover.

Toggle Parallax On.

Add overlay to ensure title legibility. Select a background color and set the opacity percentage.

Position title inside video.
Scroll up to Position, and select the position within the banner.

Display the Title outside of the Video Banner.
Toggle Title in Header to Off.

On left side under Page Options, select Content

Under Show Title, select Yes.

This will display the Title under the Video.
