noizuy/aq_edge_biased.patch

## aq_edge_biased.patch
From f694f1439f7306dcfe19f1d547d6854a3fa64f2c Mon Sep 17 00:00:00 2001
From: noizuy <85082087+noizuy@users.noreply.github.com>
Date: Fri, 18 Feb 2022 17:09:39 +0000
Subject: [PATCH] add new AQ mode (#17)

add new AQ mode

This just adds AQ mode 3's dark bias to AQ mode 4. Because of normal AQ
strength values for mode 4 not really working well with the dark bias,
an additional bias-strength parameter has been added.

(rebased on SBRC c0e4716)
---
 doc/reST/cli.rst                | 12 ++++++++++--
 source/common/frame.cpp         |  4 ++--
 source/common/param.cpp         |  7 ++++++-
 source/encoder/frameencoder.cpp |  2 +-
 source/encoder/slicetype.cpp    | 23 +++++++++++++++++------
 source/x265.h                   |  5 ++++-
 source/x265cli.cpp              |  5 +++--
 source/x265cli.h                |  1 +
 8 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/doc/reST/cli.rst b/doc/reST/cli.rst
index 9fa12fa92..29a73c8ed 100755
--- a/doc/reST/cli.rst
+++ b/doc/reST/cli.rst
@@ -1747,7 +1747,7 @@ Quality, rate control and rate distortion options
 	ignored. Slower presets will generally achieve better compression
 	efficiency (and generate smaller bitstreams). Default disabled.

-.. option:: --aq-mode <0|1|2|3|4>
+.. option:: --aq-mode <0|1|2|3|4|5>

 	Adaptive Quantization operating mode. Raise or lower per-block
 	quantization based on complexity analysis of the source image. The
@@ -1762,6 +1762,7 @@ Quality, rate control and rate distortion options
 	recommended for 8-bit encodes or low-bitrate 10-bit encodes, to
 	prevent color banding/blocking.
 	4. AQ enabled with auto-variance and edge information.
+	5. AQ enabled with auto-variance, edge information, and bias to dark scenes.

 .. option:: --aq-strength <float>

@@ -1773,6 +1774,13 @@ Quality, rate control and rate distortion options
 	Default 1.0.
 	**Range of values:** 0.0 to 3.0

+.. option:: --aq-bias-strength <float>
+
+	Adjust the strength of dark scene bias in AQ modes 3 and 5. Setting this
+	to 0 will disable the dark scene bias, meaning modes will be equivalent to
+	their unbiased counterparts (2 and 4).
+	Default 1.0.
+
 .. option:: --sbrc --no-sbrc

 	To enable and disable segment based rate control.
@@ -2399,7 +2407,7 @@ VUI fields must be manually specified.
 .. option:: --hdr10-opt, --no-hdr10-opt

 	Enable block-level luma and chroma QP optimization for HDR10 content
-	as suggested in ITU-T H-series Recommendations  Supplement 15.
+	as suggested in ITU-T H-series Recommendations Supplement 15.
 	Source video should have HDR10 characteristics such as 10-bit depth 4:2:0
 	with Bt.2020 color primaries and SMPTE ST.2084 transfer characteristics.
 	It is recommended that AQ-mode be enabled along with this feature. Default disabled.
diff --git a/source/common/frame.cpp b/source/common/frame.cpp
index e1bdc39b6..094029e71 100644
--- a/source/common/frame.cpp
+++ b/source/common/frame.cpp
@@ -131,7 +131,7 @@ bool Frame::create(x265_param *param, float* quantOffsets)
         CHECKED_MALLOC_ZERO(m_classifyCount, uint32_t, size);
     }

-    if (param->rc.aqMode == X265_AQ_EDGE || param->rc.frameSegment || (param->rc.zonefileCount && param->rc.aqMode != 0))
+    if (param->rc.aqMode == X265_AQ_EDGE || param->rc.aqMode == X265_AQ_EDGE_BIASED || param->rc.frameSegment || (param->rc.zonefileCount && param->rc.aqMode != 0))
     {
         uint32_t numCuInWidth = (param->sourceWidth + param->maxCUSize - 1) / param->maxCUSize;
         uint32_t numCuInHeight = (param->sourceHeight + param->maxCUSize - 1) / param->maxCUSize;
@@ -342,7 +342,7 @@ void Frame::destroy()
         X265_FREE_ZERO(m_classifyCount);
     }

-    if (m_param->rc.aqMode == X265_AQ_EDGE || (m_param->rc.zonefileCount && m_param->rc.aqMode != 0))
+    if (m_param->rc.aqMode == X265_AQ_EDGE || m_param->rc.aqMode == X265_AQ_EDGE_BIASED || m_param->rc.frameSegment || (m_param->rc.zonefileCount && m_param->rc.aqMode != 0))
     {
         X265_FREE(m_edgePic);
         X265_FREE(m_gaussianPic);
diff --git a/source/common/param.cpp b/source/common/param.cpp
index b13131cc8..29b8dba3e 100755
--- a/source/common/param.cpp
+++ b/source/common/param.cpp
@@ -275,6 +275,7 @@ void x265_param_default(x265_param* param)
     param->rc.hevcAq = 0;
     param->rc.qgSize = 32;
     param->rc.aqStrength = 1.0;
+    param->rc.aqBiasStrength = 1.0;
     param->rc.qpAdaptationRange = 1.0;
     param->rc.cuTree = 1;
     param->rc.rfConstantMax = 0;
@@ -766,6 +767,7 @@ int x265_zone_param_parse(x265_param* p, const char* name, const char* value)
     }
     OPT("aq-mode") p->rc.aqMode = atoi(value);
     OPT("aq-strength") p->rc.aqStrength = atof(value);
+    OPT("aq-bias-strength") p->rc.aqBiasStrength = atof(value);
     OPT("nr-intra") p->noiseReductionIntra = atoi(value);
     OPT("nr-inter") p->noiseReductionInter = atoi(value);
     OPT("limit-modes") p->limitModes = atobool(value);
@@ -1069,6 +1071,7 @@ int x265_param_parse(x265_param* p, const char* name, const char* value)
     OPT("qblur") p->rc.qblur = atof(value);
     OPT("aq-mode") p->rc.aqMode = atoi(value);
     OPT("aq-strength") p->rc.aqStrength = atof(value);
+    OPT("aq-bias-strength") p->rc.aqBiasStrength = atof(value);
     OPT("vbv-maxrate") p->rc.vbvMaxBitrate = atoi(value);
     OPT("vbv-bufsize") p->rc.vbvBufferSize = atoi(value);
     OPT("vbv-init")    p->rc.vbvBufferInit = atof(value);
@@ -1718,7 +1721,7 @@ int x265_check_params(x265_param* param)
           "Lookahead depth must be less than 256");
     CHECK(param->lookaheadSlices > 16 || param->lookaheadSlices < 0,
           "Lookahead slices must between 0 and 16");
-    CHECK(param->rc.aqMode < X265_AQ_NONE || X265_AQ_EDGE < param->rc.aqMode,
+    CHECK(param->rc.aqMode < X265_AQ_NONE || X265_AQ_EDGE_BIASED < param->rc.aqMode,
           "Aq-Mode is out of range");
     CHECK(param->rc.aqStrength < 0 || param->rc.aqStrength > 3,
           "Aq-Strength is out of range");
@@ -2281,6 +2284,7 @@ char *x265_param2string(x265_param* p, int padx, int pady)
     }
     s += sprintf(s, " aq-mode=%d", p->rc.aqMode);
     s += sprintf(s, " aq-strength=%.2f", p->rc.aqStrength);
+    s += sprintf(s, " aq-bias-strength=%.2f", p->rc.aqBiasStrength);
     BOOL(p->rc.cuTree, "cutree");
     s += sprintf(s, " zone-count=%d", p->rc.zoneCount);
     if (p->rc.zoneCount)
@@ -2576,6 +2580,7 @@ void x265_copy_params(x265_param* dst, x265_param* src)
     dst->rc.qpStep = src->rc.qpStep;
     dst->rc.aqMode = src->rc.aqMode;
     dst->rc.aqStrength = src->rc.aqStrength;
+    dst->rc.aqBiasStrength = src->rc.aqBiasStrength;
     dst->rc.vbvBufferSize = src->rc.vbvBufferSize;
     dst->rc.vbvMaxBitrate = src->rc.vbvMaxBitrate;

diff --git a/source/encoder/frameencoder.cpp b/source/encoder/frameencoder.cpp
index 6f567b9cf..aafee4f2b 100644
--- a/source/encoder/frameencoder.cpp
+++ b/source/encoder/frameencoder.cpp
@@ -471,7 +471,7 @@ void FrameEncoder::compressFrame()
     m_ssimCnt = 0;
     memset(&(m_frame->m_encData->m_frameStats), 0, sizeof(m_frame->m_encData->m_frameStats));

-    if (!m_param->bHistBasedSceneCut && m_param->rc.aqMode != X265_AQ_EDGE && m_param->recursionSkipMode == EDGE_BASED_RSKIP)
+    if (!m_param->bHistBasedSceneCut && m_param->rc.aqMode != X265_AQ_EDGE && m_param->rc.aqMode != X265_AQ_EDGE_BIASED && m_param->recursionSkipMode == EDGE_BASED_RSKIP)
     {
         int height = m_frame->m_fencPic->m_picHeight;
         int width = m_frame->m_fencPic->m_picWidth;
diff --git a/source/encoder/slicetype.cpp b/source/encoder/slicetype.cpp
index ae908e626..ba0d44c90 100644
--- a/source/encoder/slicetype.cpp
+++ b/source/encoder/slicetype.cpp
@@ -516,17 +516,17 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame *curFrame, x265_param* param)
                 double bias_strength = 0.f;
                 double strength = 0.f;

-                if (curFrame->m_frameSegment == X265_AQ_EDGE )
+                if (curFrame->m_frameSegment == X265_AQ_EDGE || curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
                     edgeFilter(curFrame, param);

-                if (curFrame->m_frameSegment == X265_AQ_EDGE  && !param->bHistBasedSceneCut && param->recursionSkipMode == EDGE_BASED_RSKIP)
+                if ((curFrame->m_frameSegment == X265_AQ_EDGE || curFrame->m_frameSegment == X265_AQ_EDGE_BIASED) && !param->bHistBasedSceneCut && param->recursionSkipMode == EDGE_BASED_RSKIP)
                 {
                     pixel* src = curFrame->m_edgePic + curFrame->m_fencPic->m_lumaMarginY * curFrame->m_fencPic->m_stride + curFrame->m_fencPic->m_lumaMarginX;
                     primitives.planecopy_pp_shr(src, curFrame->m_fencPic->m_stride, curFrame->m_edgeBitPic,
                         curFrame->m_fencPic->m_stride, curFrame->m_fencPic->m_picWidth, curFrame->m_fencPic->m_picHeight, SHIFT_TO_BITPLANE);
                 }

-                if (curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE || curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE_BIASED || curFrame->m_frameSegment == X265_AQ_EDGE)
+                if (curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE || curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE_BIASED || curFrame->m_frameSegment == X265_AQ_EDGE || curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
                 {
                     double bit_depth_correction = 1.f / (1 << (2 * (X265_DEPTH - 8)));
                     for (int blockY = 0; blockY < maxRow; blockY += loopIncr)
@@ -535,7 +535,7 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame *curFrame, x265_param* param)
                         {
                             uint32_t energy, edgeDensity, avgAngle;
                             energy = acEnergyCu(curFrame, blockX, blockY, param->internalCsp, param->rc.qgSize);
-                            if (curFrame->m_frameSegment == X265_AQ_EDGE)
+                            if (curFrame->m_frameSegment == X265_AQ_EDGE || curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
                             {
                                 edgeDensity = edgeDensityCu(curFrame, avgAngle, blockX, blockY, param->rc.qgSize);
                                 if (edgeDensity)
@@ -565,7 +565,7 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame *curFrame, x265_param* param)
                     avg_adj_pow2 /= blockCount;
                     strength = param->rc.aqStrength * avg_adj;
                     avg_adj = avg_adj - 0.5f * (avg_adj_pow2 - modeTwoConst) / avg_adj;
-                    bias_strength = param->rc.aqStrength;
+                    bias_strength = param->rc.aqBiasStrength * param->rc.aqStrength;
                 }
                 else
                     strength = param->rc.aqStrength * 1.0397f;
@@ -594,6 +594,17 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame *curFrame, x265_param* param)
                             else
                                 qp_adj = strength * (qp_adj - avg_adj);
                         }
+                        else if (param->rc.aqMode == X265_AQ_EDGE_BIASED)
+                        {
+                            inclinedEdge = curFrame->m_lowres.edgeInclined[blockXY];
+                            qp_adj = curFrame->m_lowres.qpCuTreeOffset[blockXY];
+                            double dark_bias = bias_strength * (1.f - modeTwoConst / (qp_adj * qp_adj)) / 10.f;
+                            if(inclinedEdge && (qp_adj - avg_adj > 0))
+                                qp_adj = ((strength + AQ_EDGE_BIAS) * (qp_adj - avg_adj));
+                            else
+                                qp_adj = strength * (qp_adj - avg_adj);
+                            qp_adj += dark_bias;
+                        }
                         else
                         {
                             uint32_t energy = acEnergyCu(curFrame, blockX, blockY, param->internalCsp, param->rc.qgSize);
@@ -1455,7 +1466,7 @@ void PreLookaheadGroup::processTasks(int workerThreadID)
             if (edgeIntensity < FRAME_EDGE_THRESHOLD)
                 preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_AUTO_VARIANCE : X265_AQ_AUTO_VARIANCE_BIASED;
             else
-                preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_EDGE : X265_AQ_EDGE_BIASED;
+                preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_EDGE : X265_AQ_VARIANCE;
         }
         else
             preFrame->m_frameSegment = preFrame->m_param->rc.aqMode;
diff --git a/source/x265.h b/source/x265.h
index e0be6a25a..e12a1b9fa 100644
--- a/source/x265.h
+++ b/source/x265.h
@@ -581,7 +581,7 @@ typedef enum
 #define X265_AQ_AUTO_VARIANCE        2
 #define X265_AQ_AUTO_VARIANCE_BIASED 3
 #define X265_AQ_EDGE                 4
-#define X265_AQ_EDGE_BIASED          1
+#define X265_AQ_EDGE_BIASED          5
 #define x265_ADAPT_RD_STRENGTH   4
 #define X265_REFINE_INTER_LEVELS 3
 /* NOTE! For this release only X265_CSP_I420 and X265_CSP_I444 are supported */
@@ -1413,6 +1413,9 @@ typedef struct x265_param
          * AQ is enabled. Default value: 1.0. Acceptable values between 0.0 and 3.0 */
         double    aqStrength;

+        /* Sets the bias towards dark scenes in AQ modes 3 and 5. */
+        double    aqBiasStrength;
+
         /* Delta QP range by QP adaptation based on a psycho-visual model.
          * Acceptable values between 1.0 to 6.0 */
         double    qpAdaptationRange;
diff --git a/source/x265cli.cpp b/source/x265cli.cpp
index d7e6e95c1..ea048345d 100755
--- a/source/x265cli.cpp
+++ b/source/x265cli.cpp
@@ -257,9 +257,10 @@ namespace X265_NS {
             "                                    - 0 : Disabled.\n"
             "                                    - 1 : Store/Load ctu distortion to/from the file specified in analysis-save/load.\n"
             "                                Default 0 - Disabled\n");
-        H0("   --aq-mode <integer>           Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance 3:auto variance with bias to dark scenes 4:auto variance with edge information. Default %d\n", param->rc.aqMode);
+        H0("   --aq-mode <integer>           Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance 3:auto variance with bias to dark scenes 4:auto variance with edge information 5:auto variance with edge information and bias to dark scenes. Default %d\n", param->rc.aqMode);
         H0("   --[no-]hevc-aq                Mode for HEVC Adaptive Quantization. Default %s\n", OPT(param->rc.hevcAq));
         H0("   --aq-strength <float>         Reduces blocking and blurring in flat and textured areas (0 to 3.0). Default %.2f\n", param->rc.aqStrength);
+        H0("   --aq-bias-strength <float>    Sets the bias to dark strength in AQ modes 3 and 5. Default %.2f\n", param->rc.aqBiasStrength);
         H0("   --qp-adaptation-range <float> Delta QP range by QP adaptation based on a psycho-visual model (1.0 to 6.0). Default %.2f\n", param->rc.qpAdaptationRange);
         H0("   --[no-]aq-motion              Block level QP adaptation based on the relative motion between the block and the frame. Default %s\n", OPT(param->bAQMotion));
         H1("   --[no-]sbrc                   Enables the segment based rate control, using its scene statistics. Default %s\n", OPT(param->rc.frameSegment));
@@ -1095,4 +1096,4 @@ namespace X265_NS {

 #ifdef __cplusplus
 }
-#endif
\ No newline at end of file
+#endif
diff --git a/source/x265cli.h b/source/x265cli.h
index 84c3adf25..b99b7fce6 100644
--- a/source/x265cli.h
+++ b/source/x265cli.h
@@ -184,6 +184,7 @@ static const struct option long_options[] =
     { "qp",             required_argument, NULL, 'q' },
     { "aq-mode",        required_argument, NULL, 0 },
     { "aq-strength",    required_argument, NULL, 0 },
+    { "aq-bias-strength", required_argument, NULL, 0 },
     { "sbrc",                 no_argument, NULL, 0 },
     { "no-sbrc",              no_argument, NULL, 0 },
     { "rc-grain",             no_argument, NULL, 0 },
--
2.36.1
	From f694f1439f7306dcfe19f1d547d6854a3fa64f2c Mon Sep 17 00:00:00 2001
	From: noizuy <85082087+noizuy@users.noreply.github.com>
	Date: Fri, 18 Feb 2022 17:09:39 +0000
	Subject: [PATCH] add new AQ mode (#17)

	add new AQ mode

	This just adds AQ mode 3's dark bias to AQ mode 4. Because of normal AQ
	strength values for mode 4 not really working well with the dark bias,
	an additional bias-strength parameter has been added.

	(rebased on SBRC c0e4716)
	---
	doc/reST/cli.rst \| 12 ++++++++++--
	source/common/frame.cpp \| 4 ++--
	source/common/param.cpp \| 7 ++++++-
	source/encoder/frameencoder.cpp \| 2 +-
	source/encoder/slicetype.cpp \| 23 +++++++++++++++++------
	source/x265.h \| 5 ++++-
	source/x265cli.cpp \| 5 +++--
	source/x265cli.h \| 1 +
	8 files changed, 44 insertions(+), 15 deletions(-)

	diff --git a/doc/reST/cli.rst b/doc/reST/cli.rst
	index 9fa12fa92..29a73c8ed 100755
	--- a/doc/reST/cli.rst
	+++ b/doc/reST/cli.rst
	@@ -1747,7 +1747,7 @@ Quality, rate control and rate distortion options
	ignored. Slower presets will generally achieve better compression
	efficiency (and generate smaller bitstreams). Default disabled.

	-.. option:: --aq-mode <0\|1\|2\|3\|4>
	+.. option:: --aq-mode <0\|1\|2\|3\|4\|5>

	Adaptive Quantization operating mode. Raise or lower per-block
	quantization based on complexity analysis of the source image. The
	@@ -1762,6 +1762,7 @@ Quality, rate control and rate distortion options
	recommended for 8-bit encodes or low-bitrate 10-bit encodes, to
	prevent color banding/blocking.
	4. AQ enabled with auto-variance and edge information.
	+ 5. AQ enabled with auto-variance, edge information, and bias to dark scenes.

	.. option:: --aq-strength <float>

	@@ -1773,6 +1774,13 @@ Quality, rate control and rate distortion options
	Default 1.0.
	Range of values: 0.0 to 3.0

	+.. option:: --aq-bias-strength <float>
	+
	+ Adjust the strength of dark scene bias in AQ modes 3 and 5. Setting this
	+ to 0 will disable the dark scene bias, meaning modes will be equivalent to
	+ their unbiased counterparts (2 and 4).
	+ Default 1.0.
	+
	.. option:: --sbrc --no-sbrc

	To enable and disable segment based rate control.
	@@ -2399,7 +2407,7 @@ VUI fields must be manually specified.
	.. option:: --hdr10-opt, --no-hdr10-opt

	Enable block-level luma and chroma QP optimization for HDR10 content
	- as suggested in ITU-T H-series Recommendations Supplement 15.
	+ as suggested in ITU-T H-series Recommendations Supplement 15.
	Source video should have HDR10 characteristics such as 10-bit depth 4:2:0
	with Bt.2020 color primaries and SMPTE ST.2084 transfer characteristics.
	It is recommended that AQ-mode be enabled along with this feature. Default disabled.
	diff --git a/source/common/frame.cpp b/source/common/frame.cpp
	index e1bdc39b6..094029e71 100644
	--- a/source/common/frame.cpp
	+++ b/source/common/frame.cpp
	@@ -131,7 +131,7 @@ bool Frame::create(x265_param param, float quantOffsets)
	CHECKED_MALLOC_ZERO(m_classifyCount, uint32_t, size);
	}

	- if (param->rc.aqMode == X265_AQ_EDGE \|\| param->rc.frameSegment \|\| (param->rc.zonefileCount && param->rc.aqMode != 0))
	+ if (param->rc.aqMode == X265_AQ_EDGE \|\| param->rc.aqMode == X265_AQ_EDGE_BIASED \|\| param->rc.frameSegment \|\| (param->rc.zonefileCount && param->rc.aqMode != 0))
	{
	uint32_t numCuInWidth = (param->sourceWidth + param->maxCUSize - 1) / param->maxCUSize;
	uint32_t numCuInHeight = (param->sourceHeight + param->maxCUSize - 1) / param->maxCUSize;
	@@ -342,7 +342,7 @@ void Frame::destroy()
	X265_FREE_ZERO(m_classifyCount);
	}

	- if (m_param->rc.aqMode == X265_AQ_EDGE \|\| (m_param->rc.zonefileCount && m_param->rc.aqMode != 0))
	+ if (m_param->rc.aqMode == X265_AQ_EDGE \|\| m_param->rc.aqMode == X265_AQ_EDGE_BIASED \|\| m_param->rc.frameSegment \|\| (m_param->rc.zonefileCount && m_param->rc.aqMode != 0))
	{
	X265_FREE(m_edgePic);
	X265_FREE(m_gaussianPic);
	diff --git a/source/common/param.cpp b/source/common/param.cpp
	index b13131cc8..29b8dba3e 100755
	--- a/source/common/param.cpp
	+++ b/source/common/param.cpp
	@@ -275,6 +275,7 @@ void x265_param_default(x265_param* param)
	param->rc.hevcAq = 0;
	param->rc.qgSize = 32;
	param->rc.aqStrength = 1.0;
	+ param->rc.aqBiasStrength = 1.0;
	param->rc.qpAdaptationRange = 1.0;
	param->rc.cuTree = 1;
	param->rc.rfConstantMax = 0;
	@@ -766,6 +767,7 @@ int x265_zone_param_parse(x265_param* p, const char* name, const char* value)
	}
	OPT("aq-mode") p->rc.aqMode = atoi(value);
	OPT("aq-strength") p->rc.aqStrength = atof(value);
	+ OPT("aq-bias-strength") p->rc.aqBiasStrength = atof(value);
	OPT("nr-intra") p->noiseReductionIntra = atoi(value);
	OPT("nr-inter") p->noiseReductionInter = atoi(value);
	OPT("limit-modes") p->limitModes = atobool(value);
	@@ -1069,6 +1071,7 @@ int x265_param_parse(x265_param* p, const char* name, const char* value)
	OPT("qblur") p->rc.qblur = atof(value);
	OPT("aq-mode") p->rc.aqMode = atoi(value);
	OPT("aq-strength") p->rc.aqStrength = atof(value);
	+ OPT("aq-bias-strength") p->rc.aqBiasStrength = atof(value);
	OPT("vbv-maxrate") p->rc.vbvMaxBitrate = atoi(value);
	OPT("vbv-bufsize") p->rc.vbvBufferSize = atoi(value);
	OPT("vbv-init") p->rc.vbvBufferInit = atof(value);
	@@ -1718,7 +1721,7 @@ int x265_check_params(x265_param* param)
	"Lookahead depth must be less than 256");
	CHECK(param->lookaheadSlices > 16 \|\| param->lookaheadSlices < 0,
	"Lookahead slices must between 0 and 16");
	- CHECK(param->rc.aqMode < X265_AQ_NONE \|\| X265_AQ_EDGE < param->rc.aqMode,
	+ CHECK(param->rc.aqMode < X265_AQ_NONE \|\| X265_AQ_EDGE_BIASED < param->rc.aqMode,
	"Aq-Mode is out of range");
	CHECK(param->rc.aqStrength < 0 \|\| param->rc.aqStrength > 3,
	"Aq-Strength is out of range");
	@@ -2281,6 +2284,7 @@ char x265_param2string(x265_param p, int padx, int pady)
	}
	s += sprintf(s, " aq-mode=%d", p->rc.aqMode);
	s += sprintf(s, " aq-strength=%.2f", p->rc.aqStrength);
	+ s += sprintf(s, " aq-bias-strength=%.2f", p->rc.aqBiasStrength);
	BOOL(p->rc.cuTree, "cutree");
	s += sprintf(s, " zone-count=%d", p->rc.zoneCount);
	if (p->rc.zoneCount)
	@@ -2576,6 +2580,7 @@ void x265_copy_params(x265_param* dst, x265_param* src)
	dst->rc.qpStep = src->rc.qpStep;
	dst->rc.aqMode = src->rc.aqMode;
	dst->rc.aqStrength = src->rc.aqStrength;
	+ dst->rc.aqBiasStrength = src->rc.aqBiasStrength;
	dst->rc.vbvBufferSize = src->rc.vbvBufferSize;
	dst->rc.vbvMaxBitrate = src->rc.vbvMaxBitrate;

	diff --git a/source/encoder/frameencoder.cpp b/source/encoder/frameencoder.cpp
	index 6f567b9cf..aafee4f2b 100644
	--- a/source/encoder/frameencoder.cpp
	+++ b/source/encoder/frameencoder.cpp
	@@ -471,7 +471,7 @@ void FrameEncoder::compressFrame()
	m_ssimCnt = 0;
	memset(&(m_frame->m_encData->m_frameStats), 0, sizeof(m_frame->m_encData->m_frameStats));

	- if (!m_param->bHistBasedSceneCut && m_param->rc.aqMode != X265_AQ_EDGE && m_param->recursionSkipMode == EDGE_BASED_RSKIP)
	+ if (!m_param->bHistBasedSceneCut && m_param->rc.aqMode != X265_AQ_EDGE && m_param->rc.aqMode != X265_AQ_EDGE_BIASED && m_param->recursionSkipMode == EDGE_BASED_RSKIP)
	{
	int height = m_frame->m_fencPic->m_picHeight;
	int width = m_frame->m_fencPic->m_picWidth;
	diff --git a/source/encoder/slicetype.cpp b/source/encoder/slicetype.cpp
	index ae908e626..ba0d44c90 100644
	--- a/source/encoder/slicetype.cpp
	+++ b/source/encoder/slicetype.cpp
	@@ -516,17 +516,17 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame curFrame, x265_param param)
	double bias_strength = 0.f;
	double strength = 0.f;

	- if (curFrame->m_frameSegment == X265_AQ_EDGE )
	+ if (curFrame->m_frameSegment == X265_AQ_EDGE \|\| curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
	edgeFilter(curFrame, param);

	- if (curFrame->m_frameSegment == X265_AQ_EDGE && !param->bHistBasedSceneCut && param->recursionSkipMode == EDGE_BASED_RSKIP)
	+ if ((curFrame->m_frameSegment == X265_AQ_EDGE \|\| curFrame->m_frameSegment == X265_AQ_EDGE_BIASED) && !param->bHistBasedSceneCut && param->recursionSkipMode == EDGE_BASED_RSKIP)
	{
	pixel* src = curFrame->m_edgePic + curFrame->m_fencPic->m_lumaMarginY * curFrame->m_fencPic->m_stride + curFrame->m_fencPic->m_lumaMarginX;
	primitives.planecopy_pp_shr(src, curFrame->m_fencPic->m_stride, curFrame->m_edgeBitPic,
	curFrame->m_fencPic->m_stride, curFrame->m_fencPic->m_picWidth, curFrame->m_fencPic->m_picHeight, SHIFT_TO_BITPLANE);
	}

	- if (curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE \|\| curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE_BIASED \|\| curFrame->m_frameSegment == X265_AQ_EDGE)
	+ if (curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE \|\| curFrame->m_frameSegment == X265_AQ_AUTO_VARIANCE_BIASED \|\| curFrame->m_frameSegment == X265_AQ_EDGE \|\| curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
	{
	double bit_depth_correction = 1.f / (1 << (2 * (X265_DEPTH - 8)));
	for (int blockY = 0; blockY < maxRow; blockY += loopIncr)
	@@ -535,7 +535,7 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame curFrame, x265_param param)
	{
	uint32_t energy, edgeDensity, avgAngle;
	energy = acEnergyCu(curFrame, blockX, blockY, param->internalCsp, param->rc.qgSize);
	- if (curFrame->m_frameSegment == X265_AQ_EDGE)
	+ if (curFrame->m_frameSegment == X265_AQ_EDGE \|\| curFrame->m_frameSegment == X265_AQ_EDGE_BIASED)
	{
	edgeDensity = edgeDensityCu(curFrame, avgAngle, blockX, blockY, param->rc.qgSize);
	if (edgeDensity)
	@@ -565,7 +565,7 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame curFrame, x265_param param)
	avg_adj_pow2 /= blockCount;
	strength = param->rc.aqStrength * avg_adj;
	avg_adj = avg_adj - 0.5f * (avg_adj_pow2 - modeTwoConst) / avg_adj;
	- bias_strength = param->rc.aqStrength;
	+ bias_strength = param->rc.aqBiasStrength * param->rc.aqStrength;
	}
	else
	strength = param->rc.aqStrength * 1.0397f;
	@@ -594,6 +594,17 @@ void LookaheadTLD::calcAdaptiveQuantFrame(Frame curFrame, x265_param param)
	else
	qp_adj = strength * (qp_adj - avg_adj);
	}
	+ else if (param->rc.aqMode == X265_AQ_EDGE_BIASED)
	+ {
	+ inclinedEdge = curFrame->m_lowres.edgeInclined[blockXY];
	+ qp_adj = curFrame->m_lowres.qpCuTreeOffset[blockXY];
	+ double dark_bias = bias_strength * (1.f - modeTwoConst / (qp_adj * qp_adj)) / 10.f;
	+ if(inclinedEdge && (qp_adj - avg_adj > 0))
	+ qp_adj = ((strength + AQ_EDGE_BIAS) * (qp_adj - avg_adj));
	+ else
	+ qp_adj = strength * (qp_adj - avg_adj);
	+ qp_adj += dark_bias;
	+ }
	else
	{
	uint32_t energy = acEnergyCu(curFrame, blockX, blockY, param->internalCsp, param->rc.qgSize);
	@@ -1455,7 +1466,7 @@ void PreLookaheadGroup::processTasks(int workerThreadID)
	if (edgeIntensity < FRAME_EDGE_THRESHOLD)
	preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_AUTO_VARIANCE : X265_AQ_AUTO_VARIANCE_BIASED;
	else
	- preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_EDGE : X265_AQ_EDGE_BIASED;
	+ preFrame->m_frameSegment = brightnessIntensity > FRAME_BRIGHTNESS_THRESHOLD? X265_AQ_EDGE : X265_AQ_VARIANCE;
	}
	else
	preFrame->m_frameSegment = preFrame->m_param->rc.aqMode;
	diff --git a/source/x265.h b/source/x265.h
	index e0be6a25a..e12a1b9fa 100644
	--- a/source/x265.h
	+++ b/source/x265.h
	@@ -581,7 +581,7 @@ typedef enum
	#define X265_AQ_AUTO_VARIANCE 2
	#define X265_AQ_AUTO_VARIANCE_BIASED 3
	#define X265_AQ_EDGE 4
	-#define X265_AQ_EDGE_BIASED 1
	+#define X265_AQ_EDGE_BIASED 5
	#define x265_ADAPT_RD_STRENGTH 4
	#define X265_REFINE_INTER_LEVELS 3
	/* NOTE! For this release only X265_CSP_I420 and X265_CSP_I444 are supported */
	@@ -1413,6 +1413,9 @@ typedef struct x265_param
	* AQ is enabled. Default value: 1.0. Acceptable values between 0.0 and 3.0 */
	double aqStrength;

	+ /* Sets the bias towards dark scenes in AQ modes 3 and 5. */
	+ double aqBiasStrength;
	+
	/* Delta QP range by QP adaptation based on a psycho-visual model.
	* Acceptable values between 1.0 to 6.0 */
	double qpAdaptationRange;
	diff --git a/source/x265cli.cpp b/source/x265cli.cpp
	index d7e6e95c1..ea048345d 100755
	--- a/source/x265cli.cpp
	+++ b/source/x265cli.cpp
	@@ -257,9 +257,10 @@ namespace X265_NS {
	" - 0 : Disabled.\n"
	" - 1 : Store/Load ctu distortion to/from the file specified in analysis-save/load.\n"
	" Default 0 - Disabled\n");
	- H0(" --aq-mode <integer> Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance 3:auto variance with bias to dark scenes 4:auto variance with edge information. Default %d\n", param->rc.aqMode);
	+ H0(" --aq-mode <integer> Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance 3:auto variance with bias to dark scenes 4:auto variance with edge information 5:auto variance with edge information and bias to dark scenes. Default %d\n", param->rc.aqMode);
	H0(" --[no-]hevc-aq Mode for HEVC Adaptive Quantization. Default %s\n", OPT(param->rc.hevcAq));
	H0(" --aq-strength <float> Reduces blocking and blurring in flat and textured areas (0 to 3.0). Default %.2f\n", param->rc.aqStrength);
	+ H0(" --aq-bias-strength <float> Sets the bias to dark strength in AQ modes 3 and 5. Default %.2f\n", param->rc.aqBiasStrength);
	H0(" --qp-adaptation-range <float> Delta QP range by QP adaptation based on a psycho-visual model (1.0 to 6.0). Default %.2f\n", param->rc.qpAdaptationRange);
	H0(" --[no-]aq-motion Block level QP adaptation based on the relative motion between the block and the frame. Default %s\n", OPT(param->bAQMotion));
	H1(" --[no-]sbrc Enables the segment based rate control, using its scene statistics. Default %s\n", OPT(param->rc.frameSegment));
	@@ -1095,4 +1096,4 @@ namespace X265_NS {

	#ifdef __cplusplus
	}
	-#endif
	\ No newline at end of file
	+#endif
	diff --git a/source/x265cli.h b/source/x265cli.h
	index 84c3adf25..b99b7fce6 100644
	--- a/source/x265cli.h
	+++ b/source/x265cli.h
	@@ -184,6 +184,7 @@ static const struct option long_options[] =
	{ "qp", required_argument, NULL, 'q' },
	{ "aq-mode", required_argument, NULL, 0 },
	{ "aq-strength", required_argument, NULL, 0 },
	+ { "aq-bias-strength", required_argument, NULL, 0 },
	{ "sbrc", no_argument, NULL, 0 },
	{ "no-sbrc", no_argument, NULL, 0 },
	{ "rc-grain", no_argument, NULL, 0 },
	--
	2.36.1