Index: wp-admin/includes/ajax-actions.php
===================================================================
--- wp-admin/includes/ajax-actions.php	(revision 28637)
+++ wp-admin/includes/ajax-actions.php	(working copy)
@@ -208,10 +208,8 @@ function wp_ajax_imgedit_preview() {
  * @since 3.1.0
  */
 function wp_ajax_oembed_cache() {
-	global $wp_embed;
-
-	$return = ( $wp_embed->cache_oembed( $_GET['post'] ) ) ? '1' : '0';
-	wp_die( $return );
+	$GLOBALS['wp_embed']->cache_oembed( $_GET['post'] );
+	wp_die( 0 );
 }
 
 /**
Index: wp-includes/class-wp-embed.php
===================================================================
--- wp-includes/class-wp-embed.php	(revision 28637)
+++ wp-includes/class-wp-embed.php	(working copy)
@@ -25,9 +25,6 @@ class WP_Embed {
 		// Attempts to embed all URLs in a post
 		add_filter( 'the_content', array( $this, 'autoembed' ), 8 );
 
-		// When a post is saved, invalidate the oEmbed cache
-		add_action( 'pre_post_update', array( $this, 'delete_oembed_caches' ) );
-
 		// After a post is saved, cache oEmbed items via AJAX
 		add_action( 'edit_form_advanced', array( $this, 'maybe_run_ajax_cache' ) );
 	}
@@ -186,15 +183,22 @@ class WP_Embed {
 		if ( $post_ID ) {
 
 			// Check for a cached result (stored in the post meta)
-			$cachekey = '_oembed_' . md5( $url . serialize( $attr ) );
-			if ( $this->usecache ) {
-				$cache = get_post_meta( $post_ID, $cachekey, true );
-
-				// Failures are cached
+			$key_suffix = md5( $url . serialize( $attr ) );
+			$cachekey = '_oembed_' . $key_suffix;
+			$cachekey_time = '_oembed_time_' . $key_suffix;
+			$ttl = apply_filters( 'oembed_ttl', DAY_IN_SECONDS, $url, $attr, $post_ID );
+			$cache = get_post_meta( $post_ID, $cachekey, true );
+			$cache_time = get_post_meta( $post_ID, $cachekey_time, true );
+			if ( ! $cache_time ) {
+				$cache_time = 0;
+			}
+			$cached_recently = ( time() - $cache_time ) < $ttl;
+			if ( $this->usecache || $cached_recently ) {
+				// Failures are cached. Serve one if we're using the cache.
 				if ( '{{unknown}}' === $cache )
 					return $this->maybe_make_link( $url );
 
-				if ( ! empty( $cache ) )
+				if ( ! empty( $cache ) ) {
 					/**
 					 * Filter the cached oEmbed HTML.
 					 *
@@ -208,6 +212,7 @@ class WP_Embed {
 					 * @param int    $post_ID Post ID.
 					 */
 					return apply_filters( 'embed_oembed_html', $cache, $url, $attr, $post_ID );
+				}
 			}
 
 			/**
@@ -224,9 +229,13 @@ class WP_Embed {
 			// Use oEmbed to get the HTML
 			$html = wp_oembed_get( $url, $attr );
 
-			// Cache the result
-			$cache = ( $html ) ? $html : '{{unknown}}';
-			update_post_meta( $post_ID, $cachekey, $cache );
+			// Maybe cache the result
+			if ( $html ) {
+				update_post_meta( $post_ID, $cachekey, $html );
+				update_post_meta( $post_ID, $cachekey_time, time() );
+			} elseif ( ! $cache ) {
+				update_post_meta( $post_ID, $cachekey, '{{unknown}}' );
+			}
 
 			// If there was a result, return it
 			if ( $html ) {