Casts to remove some warnings.

Added casts to remove warnings:
BUG=webm:1274

In regards to the safety of these casts they are of two types:-

- Normalized bits per (16x16) MB stored in a 32 bit int (This is safe as bits
per MB even with << 9 normalization cant overflow 32 bits. Even raw 12
bits hdr source even would only be  29 bits :- (4+4+12+9) and the encoder
imposes much stricter limits than this on max bit rate.

- Cast as part of variance calculations.  There is an internal cast up to 64 bit
for the Sum X Sum calculation, but after normalization dividing by the number
of points the result will always be <= the SSE value.

Change-Id: I4e700236ed83d6b2b1955e92e84c3b1978b9eaa0

1 files changed, 4 insertions, 1 deletions

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index d323a17a6..b853dcd08 100644
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -1788,7 +1788,10 @@ static void set_source_var_based_partition(VP9_COMP *cpi,
           d32[i].sum += d16[j]->sum;
         }
 
-        d32[i].var = d32[i].sse - (((int64_t)d32[i].sum * d32[i].sum) >> 10);
+        d32[i].var =
+            (unsigned int)(d32[i].sse -
+                           (unsigned int)(((int64_t)d32[i].sum * d32[i].sum) >>
+                                          10));
 
         index = coord_lookup[i * 4].row * mis + coord_lookup[i * 4].col;
         mi_8x8[index] = mi_upper_left + index;