Index: .env
===================================================================
--- .env	(revision 55054)
+++ .env	(working copy)
@@ -12,7 +12,7 @@
 LOCAL_PORT=8889
 
 # Where to run WordPress from. Valid options are 'src' and 'build'.
-LOCAL_DIR=src
+LOCAL_DIR=build
 
 # The PHP version to use. Valid options are 'latest', and '{version}-fpm'.
 LOCAL_PHP=latest
Index: src/js/_enqueues/vendor/mediaelement/wp-mediaelement.js
===================================================================
--- src/js/_enqueues/vendor/mediaelement/wp-mediaelement.js	(revision 55054)
+++ src/js/_enqueues/vendor/mediaelement/wp-mediaelement.js	(working copy)
@@ -19,6 +19,8 @@
 		 * @return {void}
 		 */
 		function initialize() {
+			var selectors = [];
+
 			if ( typeof _wpmejsSettings !== 'undefined' ) {
 				settings = $.extend( true, {}, _wpmejsSettings );
 			}
@@ -63,8 +65,18 @@
 				}
 			};
 
+			if ( 'undefined' === typeof settings.videoShortcodeLibrary || 'mediaelement' === settings.videoShortcodeLibrary ) {
+				selectors.push( '.wp-video-shortcode' );
+			}
+			if ( 'undefined' === typeof settings.audioShortcodeLibrary || 'mediaelement' === settings.audioShortcodeLibrary ) {
+				selectors.push( '.wp-audio-shortcode' );
+			}
+			if ( ! selectors.length ) {
+				return;
+			}
+
 			// Only initialize new media elements.
-			$( '.wp-audio-shortcode, .wp-video-shortcode' )
+			$( selectors.join( ', ' ) )
 				.not( '.mejs-container' )
 				.filter(function () {
 					return ! $( this ).parent().hasClass( 'mejs-mediaelement' );
Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 55054)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -1109,6 +1109,10 @@
 		'pluginPath'  => includes_url( 'js/mediaelement/', 'relative' ),
 		'classPrefix' => 'mejs-',
 		'stretching'  => 'responsive',
+		/** This filter is documented in wp-includes/media.php */
+		'audioShortcodeLibrary' => apply_filters( 'wp_audio_shortcode_library', 'mediaelement' ),
+		/** This filter is documented in wp-includes/media.php */
+		'videoShortcodeLibrary' => apply_filters( 'wp_video_shortcode_library', 'mediaelement' ),
 	);
 	did_action( 'init' ) && $scripts->localize(
 		'mediaelement',