diff --git a/pr_generic.cpp b/pr_generic.cpp
index 2c06c7aec..2bcf68356 100644
--- a/pr_generic.cpp
+++ b/pr_generic.cpp
@@ -299,19 +299,25 @@ void generic_packetizer_c::set_headers() {
       *(static_cast<EbmlUInteger *>
         (&GetChild<KaxVideoPixelHeight>(video))) = hvideo_pixel_height;
       if ((ti->aspect_ratio != 1.0) &&
-          ((hvideo_pixel_width / hvideo_pixel_height) != ti->aspect_ratio))
-        *(static_cast<EbmlUInteger *>
-          (&GetChild<KaxVideoDisplayHeight>(video))) = hvideo_pixel_height;
+          ((hvideo_pixel_width / hvideo_pixel_height) != ti->aspect_ratio)) {
+        KaxVideoDisplayHeight &dheight =
+          GetChild<KaxVideoDisplayHeight>(video);
+        *(static_cast<EbmlUInteger *>(&dheight)) = hvideo_pixel_height;
+        dheight.SetDefaultSize(4);
+      }
     }
 
     if (hvideo_pixel_width != -1) {
       *(static_cast<EbmlUInteger *>
         (&GetChild<KaxVideoPixelWidth>(video))) = hvideo_pixel_width;
       if ((ti->aspect_ratio != 1.0) &&
-          ((hvideo_pixel_width / hvideo_pixel_height) != ti->aspect_ratio))
-        *(static_cast<EbmlUInteger *>
-          (&GetChild<KaxVideoDisplayWidth>(video))) =
+          ((hvideo_pixel_width / hvideo_pixel_height) != ti->aspect_ratio)) {
+        KaxVideoDisplayWidth &dwidth =
+          GetChild<KaxVideoDisplayWidth>(video);
+        *(static_cast<EbmlUInteger *>(&dwidth)) =
           (uint64_t)(hvideo_pixel_height * ti->aspect_ratio);
+        dwidth.SetDefaultSize(4);
+      }
     }
 
   } else if (htrack_type == track_audio) {