diff --git a/src/js/media/views/attachment/details.js b/src/js/media/views/attachment/details.js
index 8317dbdfdada5..80f871b87ed76 100644
--- a/src/js/media/views/attachment/details.js
+++ b/src/js/media/views/attachment/details.js
@@ -266,8 +266,7 @@ Details = Attachment.extend(/** @lends wp.media.view.Attachment.Details.prototyp
 
 		wp.media.mixin.removeAllPlayers();
 		this.$( 'audio, video' ).each( function (i, elem) {
-			var el = wp.media.view.MediaDetails.prepareSrc( elem );
-			new window.MediaElementPlayer( el, wp.media.mixin.mejsSettings );
+			new window.MediaElementPlayer( elem, wp.media.mixin.mejsSettings );
 		} );
 	}
 });
diff --git a/src/js/media/views/audio-details.js b/src/js/media/views/audio-details.js
index afafca3080673..b51580cbbd338 100644
--- a/src/js/media/views/audio-details.js
+++ b/src/js/media/views/audio-details.js
@@ -25,7 +25,7 @@ AudioDetails = MediaDetails.extend(/** @lends wp.media.view.AudioDetails.prototy
 			if ( audio.is(':hidden') ) {
 				audio.show();
 			}
-			this.media = MediaDetails.prepareSrc( audio.get(0) );
+			this.media = audio.get(0);
 		} else {
 			audio.hide();
 			this.media = false;
diff --git a/src/js/media/views/media-details.js b/src/js/media/views/media-details.js
index 5fdeb64a05cd1..13dd9ee51db73 100644
--- a/src/js/media/views/media-details.js
+++ b/src/js/media/views/media-details.js
@@ -180,24 +180,15 @@ MediaDetails = AttachmentDisplay.extend(/** @lends wp.media.view.MediaDetails.pr
 		this.$( '.embed-media-settings' ).scrollTop( 0 );
 	}
 },/** @lends wp.media.view.MediaDetails */{
-	instances : 0,
 	/**
-	 * When multiple players in the DOM contain the same src, things get weird.
+	 * Formerly appended a cache-busting query arg to each media source.
 	 *
-	 * @param {HTMLElement} elem The HTML element containing the media sources to be prepared.
-	 * @return {HTMLElement} The prepared element.
+	 * @deprecated 7.3.0 Returns the element unchanged.
+	 *
+	 * @param {HTMLElement} elem The HTML element containing the media sources.
+	 * @return {HTMLElement} The unchanged element.
 	 */
 	prepareSrc : function( elem ) {
-		var i = MediaDetails.instances++;
-		_.each( $( elem ).find( 'source' ), function( source ) {
-			source.src = [
-				source.src,
-				source.src.indexOf('?') > -1 ? '&' : '?',
-				'_=',
-				i
-			].join('');
-		} );
-
 		return elem;
 	}
 });
diff --git a/src/js/media/views/video-details.js b/src/js/media/views/video-details.js
index ac5c91e3c634f..532173d2ade84 100644
--- a/src/js/media/views/video-details.js
+++ b/src/js/media/views/video-details.js
@@ -27,7 +27,7 @@ VideoDetails = MediaDetails.extend(/** @lends wp.media.view.VideoDetails.prototy
 			}
 
 			if ( ! video.hasClass( 'youtube-video' ) && ! video.hasClass( 'vimeo-video' ) ) {
-				this.media = MediaDetails.prepareSrc( video.get(0) );
+				this.media = video.get(0);
 			} else {
 				this.media = video.get(0);
 			}
diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 4cd69ade6cbb7..fa6f1d20e7393 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -3683,8 +3683,7 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 			}
 
 			$type  = wp_check_filetype( $atts[ $fallback ], wp_get_mime_types() );
-			$url   = add_query_arg( '_', $instance, $atts[ $fallback ] );
-			$html .= sprintf( $source, $type['type'], esc_url( $url ) );
+			$html .= sprintf( $source, $type['type'], esc_url( $atts[ $fallback ] ) );
 		}
 	}
 
@@ -3966,8 +3965,7 @@ function wp_video_shortcode( $attr, $content = '' ) {
 			} else {
 				$type = wp_check_filetype( $atts[ $fallback ], wp_get_mime_types() );
 			}
-			$url   = add_query_arg( '_', $instance, $atts[ $fallback ] );
-			$html .= sprintf( $source, $type['type'], esc_url( $url ) );
+			$html .= sprintf( $source, $type['type'], esc_url( $atts[ $fallback ] ) );
 		}
 	}
 
diff --git a/tests/phpunit/tests/media.php b/tests/phpunit/tests/media.php
index af84065113267..261ec42846e58 100644
--- a/tests/phpunit/tests/media.php
+++ b/tests/phpunit/tests/media.php
@@ -1550,7 +1550,7 @@ static function ( $html, $attr, $content, $id ) use ( &$instance ) {
 
 		$expected = '<div style="width: ' . $width . 'px;" class="wp-video">' .
 			'<video class="wp-video-shortcode" id="video-' . $post_id . '-' . $instance . '" width="' . $width . '" height="' . $h . '" preload="metadata" controls="controls">' .
-			'<source type="video/mp4" src="http://domain.tld/wp-content/uploads/2013/12/xyz.mp4?_=' . $instance . '" />' .
+			'<source type="video/mp4" src="http://domain.tld/wp-content/uploads/2013/12/xyz.mp4" />' .
 			'<!-- WebM/VP8 for Firefox4, Opera, and Chrome --><source type="video/webm" src="myvideo.webm" />' .
 			'<!-- Ogg/Vorbis for older Firefox and Opera versions --><source type="video/ogg" src="myvideo.ogv" />' .
 			'<!-- Optional: Add subtitles for each language --><track kind="subtitles" src="subtitles.srt" srclang="en" />' .