[x265] [PATCH] optimize c1c2 context set update logic in rdoQuant

[Min Chen]

# HG changeset patch
# User Min Chen <chenm003 at 163.com>
# Date 1428582384 -28800
# Node ID 766b8a5f174e20b943387ef8897d21f3ef27eb5f
# Parent  7f2d92923de47e7e40f04ff27ed70074b0dca9d3
optimize c1c2 context set update logic in rdoQuant
---
 source/common/quant.cpp |   31 ++++++++++++-------------------
 1 files changed, 12 insertions(+), 19 deletions(-)

diff -r 7f2d92923de4 -r 766b8a5f174e source/common/quant.cpp
--- a/source/common/quant.cpp	Wed Apr 08 14:51:00 2015 -0500
+++ b/source/common/quant.cpp	Thu Apr 09 20:26:24 2015 +0800
@@ -559,11 +559,6 @@
     uint64_t sigCoeffGroupFlag64 = 0;
 
     uint32_t ctxSet      = 0;
-    int    c1            = 1;
-    int    c2            = 0;
-    uint32_t goRiceParam = 0;
-    uint32_t c1Idx       = 0;
-    uint32_t c2Idx       = 0;
     int cgLastScanPos    = -1;
     int lastScanPos      = -1;
     const uint32_t cgSize = (1 << MLS_CG_SIZE); /* 4x4 num coef = 16 */
@@ -599,6 +594,11 @@
 
         const int patternSigCtx = calcPatternSigCtx(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, cgStride);
 
+        int    c1            = 1;
+        int    c2            = 0;
+        uint32_t goRiceParam = 0;
+        uint32_t c1Idx       = 0;
+        uint32_t c2Idx       = 0;
         /* iterate over coefficients in each group in reverse scan order */
         for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--)
         {
@@ -800,20 +800,6 @@
                 }
                 else if ((c1 < 3) && (c1 > 0) && level)
                     c1++;
-
-                /* context set update */
-                if (!(scanPos % SCAN_SET_SIZE) && scanPos)
-                {
-                    c2 = 0;
-                    goRiceParam = 0;
-
-                    c1Idx = 0;
-                    c2Idx = 0;
-                    ctxSet = (scanPos == SCAN_SET_SIZE || !bIsLuma) ? 0 : 2;
-                    X265_CHECK(c1 >= 0, "c1 is negative\n");
-                    ctxSet -= ((int32_t)(c1 - 1) >> 31);
-                    c1 = 1;
-                }
             }
 
             cgRdStats.sigCost += costSig[scanPos];
@@ -829,6 +815,13 @@
             }
         } /* end for (scanPosinCG) */
 
+        /* context set update */
+        {
+            ctxSet = (cgScanPos == 1 || !bIsLuma) ? 0 : 2;
+            X265_CHECK(c1 >= 0, "c1 is negative\n");
+            ctxSet -= ((int32_t)(c1 - 1) >> 31);
+        }
+
         costCoeffGroupSig[cgScanPos] = 0;
 
         if (cgLastScanPos < 0)