diff --git a/views/bootstrap/class.ViewDocument.php b/views/bootstrap/class.ViewDocument.php
index 27461d1a1..c77a156ea 100644
--- a/views/bootstrap/class.ViewDocument.php
+++ b/views/bootstrap/class.ViewDocument.php
@@ -370,6 +370,7 @@ class SeedDMS_View_ViewDocument extends SeedDMS_Bootstrap_Style {
 			case 'video/avi':
 			case 'video/msvideo':
 			case 'video/x-msvideo':
+			case 'video/x-matroska':
 				$this->contentHeading(getMLText("preview"));
 	?>
 			<video controls style="width: 100%;">