diff --git a/src/FFMpeg/Format/Video/X264.php b/src/FFMpeg/Format/Video/X264.php
index fd57231..f2d4018 100644
--- a/src/FFMpeg/Format/Video/X264.php
+++ b/src/FFMpeg/Format/Video/X264.php
@@ -52,4 +52,9 @@ class X264 extends DefaultVideo
     {
         return 2;
     }
+
+    public function getModulus()
+    {
+        return 2;
+    }
 }