The get_header_video_settings() WordPress PHP function retrieves the header video settings.
Usage
To use the function, simply call it like this:
$video_settings = get_header_video_settings();
Parameters
This function does not have any parameters.
More information
See WordPress Developer Resources: get_header_video_settings
Examples
Display header video URL
Retrieve header video settings and display the video URL.
$video_settings = get_header_video_settings(); echo 'Header video URL: ' . $video_settings['videoUrl'];
Show header video thumbnail
Retrieve header video settings and display the video thumbnail image.
$video_settings = get_header_video_settings(); echo '<img src="' . $video_settings['thumbnailUrl'] . '" alt="Video Thumbnail">';
Conditional display of header video
Display header video only if it is set in the customizer.
$video_settings = get_header_video_settings();
if (!empty($video_settings['videoUrl'])) {
    echo '<video src="' . $video_settings['videoUrl'] . '" autoplay loop></video>';
}
Display header video with custom width and height
Retrieve header video settings and display the video with custom dimensions.
$video_settings = get_header_video_settings(); echo '<video src="' . $video_settings['videoUrl'] . '" width="640" height="360" autoplay loop></video>';
Check if header video is an external URL
Check if the header video is an external URL (e.g., YouTube, Vimeo) or a local video file.
$video_settings = get_header_video_settings();
$is_external = (bool) $video_settings['externalVideo'];
if ($is_external) {
    echo 'The header video is an external URL.';
} else {
    echo 'The header video is a local file.';
}