[x265] [PATCH 2 of 2] Using weighted lowres ref frames in cost estimation in lookahead

[shazeb at multicorewareinc.com]

# HG changeset patch
# User Shazeb Nawaz Khan <shazeb at multicorewareinc.com>
# Date 1384346304 -19800
#      Wed Nov 13 18:08:24 2013 +0530
# Node ID a7b6c5a45c69814e35473af81a5d2a0299d634ca
# Parent  213808a2069d21c49a4d5e99d71ad71b8af344b8
Using weighted lowres ref frames in cost estimation in lookahead

diff -r 213808a2069d -r a7b6c5a45c69 source/common/lowres.cpp
--- a/source/common/lowres.cpp	Wed Nov 13 18:03:02 2013 +0530
+++ b/source/common/lowres.cpp	Wed Nov 13 18:08:24 2013 +0530
@@ -40,6 +40,7 @@
     int cuWidth = (width + X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
     int cuHeight = (lines + X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
     int cuCount = cuWidth * cuHeight;
+    bufferSize = lumaStride * (lines + 2 * orig->getLumaMarginY());
 
     /* rounding the width to multiple of lowres CU size */
     width = cuWidth * X265_LOWRES_CU_SIZE;
@@ -115,6 +116,18 @@
     X265_FREE(invQscaleFactor);
 }
 
+void Lowres::initWeighted(Lowres *ref, wpScalingParam *w)
+{
+    isWeighted = true;
+    int correction = (IF_INTERNAL_PREC - X265_DEPTH);
+    for (int i = 0; i < 4; i++)
+    {
+        //Adding (IF_INTERNAL_PREC - X265_DEPTH) to cancel effect of pixel to short conversion inside the primitive
+        primitives.weightpUniPixel(ref->buffer[i], this->buffer[i], lumaStride, lumaStride, lumaStride, (int) bufferSize / lumaStride, w->inputWeight, (1<<(w->log2WeightDenom - 1 + correction)), (w->log2WeightDenom + correction), w->inputOffset);
+    }
+    fpelPlane = lowresPlane[0];
+}
+
 // (re) initialize lowres state
 void Lowres::init(TComPicYuv *orig, int poc, int type, int bframes)
 {
diff -r 213808a2069d -r a7b6c5a45c69 source/common/lowres.h
--- a/source/common/lowres.h	Wed Nov 13 18:03:02 2013 +0530
+++ b/source/common/lowres.h	Wed Nov 13 18:08:24 2013 +0530
@@ -33,6 +33,7 @@
 
 class TComPic;
 class TComPicYuv;
+typedef struct WpScalingParam wpScalingParam;
 
 struct ReferencePlanes
 {
@@ -100,6 +101,7 @@
 struct Lowres : public ReferencePlanes
 {
     pixel *buffer[4];
+    int bufferSize;
 
     int    frameNum;         // Presentation frame number
     int    sliceType;        // Slice type decided by lookahead
@@ -132,6 +134,7 @@
     void create(TComPic *pic, int bframes, int32_t *aqMode);
     void destroy(int bframes);
     void init(TComPicYuv *orig, int poc, int sliceType, int bframes);
+    void initWeighted(Lowres *ref, wpScalingParam *w);
 };
 }
 
diff -r 213808a2069d -r a7b6c5a45c69 source/encoder/slicetype.cpp
--- a/source/encoder/slicetype.cpp	Wed Nov 13 18:03:02 2013 +0530
+++ b/source/encoder/slicetype.cpp	Wed Nov 13 18:08:24 2013 +0530
@@ -79,12 +79,16 @@
     widthInCU = ((cfg->param.sourceWidth / 2) + X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
     heightInCU = ((cfg->param.sourceHeight / 2) + X265_LOWRES_CU_SIZE - 1) >> X265_LOWRES_CU_BITS;
 
+    weightedRef.buffer[0] = NULL;
+
     lhrows = new LookaheadRow[heightInCU];
     for (int i = 0; i < heightInCU; i++)
     {
         lhrows[i].widthInCU = widthInCU;
         lhrows[i].heightInCU = heightInCU;
         lhrows[i].frames = frames;
+        lhrows[i].weightedRef = &weightedRef;
+        lhrows[i].cfg = cfg;
     }
 }
 
@@ -127,7 +131,11 @@
 void Lookahead::addPicture(TComPic *pic, int sliceType)
 {
     pic->m_lowres.init(pic->getPicYuvOrg(), pic->getSlice()->getPOC(), sliceType, cfg->param.bframes);
-
+    if (weightedRef.buffer[0] == NULL)
+    {
+        // Just using width/height data from the pic to create a standalone Lowres object
+        weightedRef.create(pic, cfg->param.bframes, &cfg->param.rc.aqMode);
+    }
     inputQueue.pushBack(*pic);
     if (inputQueue.size() >= cfg->param.lookaheadDepth)
         slicetypeDecide();
@@ -347,6 +355,14 @@
             if( cfg->param.bEnableWeightedPred && b==p1)
             {
                 weightsAnalyse(b, p0, 1, &wp);
+                if (wp.bPresentFlag)
+                {
+                    weightedRef.initWeighted(frames[p0], &wp);
+                }
+                else
+                {
+                    weightedRef.isWeighted = false;
+                }
             }
             bDoSearch[0] = b != p0 && fenc->lowresMvs[0][b - p0 - 1][0].x == 0x7FFF;
             bDoSearch[1] = b != p1 && fenc->lowresMvs[1][p1 - b - 1][0].x == 0x7FFF;
@@ -437,6 +453,11 @@
     Lowres *fref1 = frames[p1];
     Lowres *fenc  = frames[b];
 
+    if (weightedRef->isWeighted)
+    {
+        fref0 = weightedRef;
+    }
+
     const int bBidir = (b < p1);
     const int cuXY = cux + cuy * widthInCU;
     const int cuSize = X265_LOWRES_CU_SIZE;