// WP_Ajax & oEmbed
add_action( 'wp_ajax_acf_oembed', __NAMESPACE__ . '\\acf_oembed_callback' );
add_action( 'wp_ajax_nopriv_acf_oembed', __NAMESPACE__ . '\\acf_oembed_callback' );
function acf_oembed_callback() {
	$post_id = $_GET['post_id'];

	$oembed = get_field('oembed', $post_id);

	var_dump($oembed);

	wp_die();
}