diff --git a/vp8/encoder/ethreading.c b/vp8/encoder/ethreading.c
index 2cd24da67943b11ea1b4401ab75969cc25a05ea8..7b5cfe0ee966f66e3e73242703d934d69b0a7b81 100644
--- a/vp8/encoder/ethreading.c
+++ b/vp8/encoder/ethreading.c
@@ -310,6 +310,7 @@ static void setup_mbby_copy(MACROBLOCK *mbdst, MACROBLOCK *mbsrc)
     for (i = 0; i < 25; i++)
     {
         z->block[i].quant           = x->block[i].quant;
+        z->block[i].quant_fast      = x->block[i].quant_fast;
         z->block[i].quant_shift     = x->block[i].quant_shift;
         z->block[i].zbin            = x->block[i].zbin;
         z->block[i].zrun_zbin_boost   = x->block[i].zrun_zbin_boost;