Limit video dimensions.

src/Parsers/BBCode/Tags/VideoTag.php

@@ -19,7 +19,7 @@ final class VideoTag extends BBCodeTag
                 }
 
                 $mediaUrl = proxy_media_url($matches[1]);
-                return "<video controls src='{$mediaUrl}'></video>";
+                return sprintf('<video controls src="%s" style="max-width:100%%;max-height:100%%;"></video>', $mediaUrl);
             },
             $text
         );