From: Dark Shikari <darkshikari@gmail.com>
Subject: [PATCH] Add fade compensation function

 common/common.c     |    5 +++++
 encoder/encoder.c   |    7 +++++++
 encoder/slicetype.c |    4 ++--
 x264.c              |    3 +++
 x264.h              |    1 +
 5 files changed, 18 insertions(+), 2 deletions(-)

Index: common/common.c
===================================================================
--- common/common_orig.c
+++ common/common.c
@@ -920,6 +920,8 @@ int x264_param_parse( x264_param_t *p, const char *name, const char *value )
         p->rc.i_aq_mode = atoi(value);
     OPT("aq-strength")
         p->rc.f_aq_strength = atof(value);
+    OPT("fade-compensate")
+        p->rc.f_fade_compensate = atof(value);
     OPT("pass")
     {
         int pass = x264_clip3( atoi(value), 0, 3 );
@@ -1196,7 +1198,10 @@ char *x264_param2string( x264_param_t *p, int b_res )
     s += sprintf( s, " subme=%d", p->analyse.i_subpel_refine );
     s += sprintf( s, " psy=%d", p->analyse.b_psy );
     if( p->analyse.b_psy )
+    {
+        s += sprintf( s, " fade_compensate=%.2f", p->rc.f_fade_compensate );
         s += sprintf( s, " psy_rd=%.2f:%.2f", p->analyse.f_psy_rd, p->analyse.f_psy_trellis );
+    }
     s += sprintf( s, " mixed_ref=%d", p->analyse.b_mixed_references );
     s += sprintf( s, " me_range=%d", p->analyse.i_me_range );
     s += sprintf( s, " chroma_me=%d", p->analyse.b_chroma_me );
Index: encoder/encoder.c
===================================================================
--- encoder/encoder_orig.c
+++ encoder/encoder.c
@@ -686,10 +686,17 @@ static int x264_validate_parameters( x264_t *h )
     if( !h->param.b_cabac )
         h->param.analyse.i_trellis = 0;
     h->param.analyse.i_trellis = x264_clip3( h->param.analyse.i_trellis, 0, 2 );
+    if( h->param.analyse.i_weighted_pred == X264_WEIGHTP_NONE )
+        h->param.rc.f_fade_compensate += 0.1;
+    if( h->param.analyse.i_weighted_pred == X264_WEIGHTP_BLIND )
+        h->param.rc.f_fade_compensate = 0;
+    if( !h->param.rc.b_mb_tree )
+        h->param.rc.f_fade_compensate = 0;
     if( !h->param.analyse.b_psy )
     {
         h->param.analyse.f_psy_rd = 0;
         h->param.analyse.f_psy_trellis = 0;
+        h->param.rc.f_fade_compensate = 0;
     }
     if( !h->param.analyse.i_trellis )
         h->param.analyse.f_psy_trellis = 0;
Index: encoder/slicetype.c
===================================================================
--- encoder/slicetype_orig.c
+++ encoder/slicetype.c
@@ -205,7 +205,7 @@ void x264_weights_analyse( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, int
     else
         SET_WEIGHT( weights[0], 1, minscale, mindenom, minoff );

-    if( h->param.analyse.i_weighted_pred == X264_WEIGHTP_FAKE && weights[0].weightfn )
+    if( weights[0].weightfn )
         fenc->f_weighted_cost_delta[i_delta_index] = (float)minscore / origscore;

     if( weights[0].weightfn && b_lookahead )
@@ -630,7 +630,7 @@ static void x264_macroblock_tree_finish( x264_t *h, x264_frame_t *frame, int ref
     x264_emms();
     float weightdelta = 0.0;
     if( ref0_distance && frame->f_weighted_cost_delta[ref0_distance-1] > 0 )
-        weightdelta = (1.0 - frame->f_weighted_cost_delta[ref0_distance-1]);
+        weightdelta = (1.0 - frame->f_weighted_cost_delta[ref0_distance-1]) * 10.0f * h->param.rc.f_fade_compensate;

     /* Allow the strength to be adjusted via qcompress, since the two
      * concepts are very similar. */
Index: x264.c
===================================================================
--- x264_orig.c
+++ x264.c
@@ -528,6 +528,8 @@ static void Help( x264_param_t *defaults, int longhelp )
         "                                  - 2: Auto-variance AQ (experimental)\n", defaults->rc.i_aq_mode );
     H1( "      --aq-strength <float>   Reduces blocking and blurring in flat and\n"
         "                              textured areas. [%.1f]\n", defaults->rc.f_aq_strength );
+    H1( "      --fade-compensate <float> Allocate more bits to fades [%.1f]\n", defaults->rc.f_fade_compensate );
+    H2( "                                  Approximate sane range: 0.0 - 1.0\n" );
     H1( "\n" );
     H0( "  -p, --pass <integer>        Enable multipass ratecontrol\n"
         "                                  - 1: First pass, creates stats file\n"
@@ -811,6 +813,7 @@ static struct option long_options[] =
     { "no-dct-decimate",   no_argument, NULL, 0 },
     { "aq-strength", required_argument, NULL, 0 },
     { "aq-mode",     required_argument, NULL, 0 },
+    { "fade-compensate", required_argument, NULL, 0 },
     { "deadzone-inter", required_argument, NULL, '0' },
     { "deadzone-intra", required_argument, NULL, '0' },
     { "level",       required_argument, NULL, 0 },
Index: x264.h
===================================================================
--- x264_orig.h
+++ x264.h
@@ -355,6 +355,7 @@ typedef struct x264_param_t

         int         i_aq_mode;      /* psy adaptive QP. (X264_AQ_*) */
         float       f_aq_strength;
+        float       f_fade_compensate; /* Give more bits to fades. */
         int         b_mb_tree;      /* Macroblock-tree ratecontrol. */
         int         i_lookahead;