diff --git a/pack-vid b/pack-vid
index d8e36f1..6e062e2 100755
--- a/pack-vid
+++ b/pack-vid
@@ -340,6 +340,7 @@ function convert( $src, $dest, $options ) {
         if ( $vibrance ) {
             $filters[] = "vibrance=$vibrance";
         }
+        $filters[] = "format=yuv420p";
     } else {
         $filters[] = "format=yuv420p";
     }