diff --git a/pack-vid b/pack-vid
index 54bb79c..2ad6b7d 100755
--- a/pack-vid
+++ b/pack-vid
@@ -345,7 +345,7 @@ function convert( $src, $dest, $options ) {
     }
     $filters[] = "scale=w=$scaleWidth:h=$scaleHeight";
     if ( $hdr ) {
-        $filters[] = "zscale=t=linear";
+        $filters[] = "zscale=t=linear:p=709:m=709";
         if ( $exposure ) {
             $filters[] = "exposure=$exposure";
         }