diff --git a/av1/encoder/block.h b/av1/encoder/block.h
index ae97d5e..c74b394 100644
--- a/av1/encoder/block.h
+++ b/av1/encoder/block.h
@@ -31,7 +31,7 @@
 } DIFF;
 
 typedef struct macroblock_plane {
-  DECLARE_ALIGNED(16, int16_t, src_diff[MAX_SB_SQUARE]);
+  DECLARE_ALIGNED(32, int16_t, src_diff[MAX_SB_SQUARE]);
   tran_low_t *qcoeff;
   tran_low_t *coeff;
   uint16_t *eobs;