commit a0993703702ba1c1af9d4c04debe3f040f18a98d
author Ronald S. Bultje <rbultje@google.com> Wed Nov 14 15:02:43 2012 -0800
committer Ronald S. Bultje <rbultje@google.com> Wed Nov 14 15:18:21 2012 -0800
tree e1798da15e5b50ddcbb03e63bb4817394606de2b
parent 1e3dd49fe389dcbd0745dafa556235d118674515

Prevent overflow in variance32x32.

Change-Id: I478878c78ef8a770186622d987d318176827ef5f

vp9/encoder/variance_c.c

diff --git a/vp9/encoder/variance_c.c b/vp9/encoder/variance_c.c
index 8ac956e..7703ef0 100644
--- a/vp9/encoder/variance_c.c
+++ b/vp9/encoder/variance_c.c
@@ -12,7 +12,7 @@
 #include "variance.h"
 #include "vp9/common/filter.h"
 #include "vp9/common/subpelvar.h"
-
+#include "vpx/vpx_integer.h"
 
 unsigned int vp9_get_mb_ss_c(const short *src_ptr) {
   unsigned int i, sum = 0;
@@ -37,8 +37,7 @@
 
   variance(src_ptr, source_stride, ref_ptr, recon_stride, 32, 32, &var, &avg);
   *sse = var;
-  // TODO(rbultje): in extreme cases these products will rollover.
-  return (var - (((unsigned int)avg * avg) >> 10));
+  return (var - (((int64_t)avg * avg) >> 10));
 }
 #endif