[x265] [PATCH 2 of 2] improve ctuLumaLevel logic by Sad and CMOV

[Min Chen]

# HG changeset patch
# User Min Chen <chenm003 at 163.com>
# Date 1439331239 25200
# Node ID 66b7f9300b8c392df7f1d597bec0fd099071c1af
# Parent  aeae99c6c24580b510cdaf119bb6921f62c78368
improve ctuLumaLevel logic by Sad and CMOV
---
 source/encoder/frameencoder.cpp |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff -r aeae99c6c245 -r 66b7f9300b8c source/encoder/frameencoder.cpp
--- a/source/encoder/frameencoder.cpp	Tue Aug 11 15:13:55 2015 -0700
+++ b/source/encoder/frameencoder.cpp	Tue Aug 11 15:13:59 2015 -0700
@@ -991,13 +991,14 @@
         }
 
         /* calculate maximum and average luma levels */
-        uint32_t ctuLumaLevel = 0;
+        static const pixel dummy_zero[MAX_CU_SIZE] = {0};
+        uint32_t ctuLumaLevel = primitives.pu[best.fencYuv->m_part].sad(best.fencYuv->m_buf[0], best.fencYuv->m_size, dummy_zero, 0);
         uint32_t ctuNoOfPixels = best.fencYuv->m_size * best.fencYuv->m_size;
         for (uint32_t i = 0; i < ctuNoOfPixels; i++)
         {
             pixel p = best.fencYuv->m_buf[0][i];
-            ctuLumaLevel += p;
-            curRow.rowStats.maxLumaLevel = X265_MAX(p, curRow.rowStats.maxLumaLevel);
+            if (p > curRow.rowStats.maxLumaLevel)
+                curRow.rowStats.maxLumaLevel = p;
         }
         curRow.rowStats.lumaLevel += (double)(ctuLumaLevel) / ctuNoOfPixels;