diff --git a/lib/activitystreamjsondocument.php b/lib/activitystreamjsondocument.php
index c67fc5a42f..9964f1e60c 100644
--- a/lib/activitystreamjsondocument.php
+++ b/lib/activitystreamjsondocument.php
@@ -201,9 +201,9 @@ class ActivityStreamsMediaLink extends ActivityStreamsLink
     {
         parent::__construct($url, $rel, $mediaType);
         $this->linkDict = array(
-            'width'      => $width,
-            'height'     => $height,
-            'duration'   => $duration
+            'width'      => intval($width),
+            'height'     => intval($height),
+            'duration'   => intval($duration)
         );
     }