diff -uNrp a/common/common.c b/common/common.c
--- a/common/common.c	2009-12-05 21:34:24 +0200
+++ b/common/common.c	2009-12-05 22:15:15 +0200
@@ -101,6 +101,7 @@ void    x264_param_default( x264_param_t
     param->rc.f_pb_factor = 1.3;
     param->rc.i_aq_mode = X264_AQ_VARIANCE;
     param->rc.f_aq_strength = 1.0;
+    param->rc.f_aq_offset_strength = 0;
     param->rc.i_lookahead = 40;
 
     param->rc.b_stat_write = 0;
@@ -577,7 +578,20 @@ int x264_param_parse( x264_param_t *p, c
     OPT("aq-mode")
         p->rc.i_aq_mode = atoi(value);
     OPT("aq-strength")
-        p->rc.f_aq_strength = atof(value);
+    {
+        if( 2 == sscanf( value, "%f:%f", &p->rc.f_aq_strength, &p->rc.f_aq_offset_strength ) ||
+            2 == sscanf( value, "%f,%f", &p->rc.f_aq_strength, &p->rc.f_aq_offset_strength ) )
+        { }
+        else if( sscanf( value, "%f", &p->rc.f_aq_strength ) )
+        {
+            p->rc.f_aq_offset_strength = 0;
+        }
+        else
+        {
+            p->rc.f_aq_strength = 0;
+            p->rc.f_aq_offset_strength = 0;
+        }
+    }
     OPT("pass")
     {
         int i = x264_clip3( atoi(value), 0, 3 );
@@ -942,7 +956,11 @@ char *x264_param2string( x264_param_t *p
             s += sprintf( s, " pb_ratio=%.2f", p->rc.f_pb_factor );
         s += sprintf( s, " aq=%d", p->rc.i_aq_mode );
         if( p->rc.i_aq_mode )
+        {
             s += sprintf( s, ":%.2f", p->rc.f_aq_strength );
+            if( p->rc.f_aq_offset_strength != 0 )
+                s += sprintf( s, ":%.2f", p->rc.f_aq_offset_strength );
+        }
         if( p->rc.psz_zones )
             s += sprintf( s, " zones=%s", p->rc.psz_zones );
         else if( p->rc.i_zones )
diff -uNrp a/encoder/encoder.c b/encoder/encoder.c
--- a/encoder/encoder.c	2009-12-05 21:34:24 +0200
+++ b/encoder/encoder.c	2009-12-05 22:15:59 +0200
@@ -624,8 +624,9 @@ static int x264_validate_parameters( x26
     else
         h->mb.i_psy_trellis = 0;
     h->param.analyse.i_chroma_qp_offset = x264_clip3(h->param.analyse.i_chroma_qp_offset, -12, 12);
-    h->param.rc.i_aq_mode = x264_clip3( h->param.rc.i_aq_mode, 0, 2 );
-    h->param.rc.f_aq_strength = x264_clip3f( h->param.rc.f_aq_strength, 0, 3 );
+    h->param.rc.i_aq_mode = x264_clip3( h->param.rc.i_aq_mode, 0, 3 );
+    h->param.rc.f_aq_offset_strength = h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE ? x264_clip3f( h->param.rc.f_aq_offset_strength, 0, 3 ) : 0;
+    if( h->param.rc.f_aq_strength == 0 && h->param.rc.f_aq_offset_strength == 0 )
     if( h->param.rc.f_aq_strength == 0 )
         h->param.rc.i_aq_mode = 0;
     /* MB-tree requires AQ to be on, even if the strength is zero. */
@@ -633,6 +634,7 @@ static int x264_validate_parameters( x26
     {
         h->param.rc.i_aq_mode = 1;
         h->param.rc.f_aq_strength = 0;
+        h->param.rc.f_aq_offset_strength = 0;
     }
     if( h->param.rc.b_mb_tree && h->param.i_bframe_pyramid )
     {
diff -uNrp a/encoder/ratecontrol.c b/encoder/ratecontrol.c
--- a/encoder/ratecontrol.c	2009-12-05 21:34:24 +0200
+++ b/encoder/ratecontrol.c	2009-12-05 22:17:36 +0200
@@ -215,9 +215,10 @@ void x264_adaptive_quant_frame( x264_t *
      * FIXME: while they're written in 5 significant digits, they're only tuned to 2. */
     int mb_x, mb_y;
     float strength;
-    float avg_adj = 0.f;
+    float avg_adj = 0.0f;
+    float avg_offset = 0.0f;
     /* Need to init it anyways for MB tree. */
-    if( h->param.rc.f_aq_strength == 0 )
+    if( h->param.rc.f_aq_strength == 0 && h->param.rc.f_aq_offset_strength == 0 )
     {
         int mb_xy;
         memset( frame->f_qp_offset, 0, h->mb.i_mb_count * sizeof(float) );
@@ -228,7 +229,9 @@ void x264_adaptive_quant_frame( x264_t *
         return;
     }
 
-    if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
+    if( h->param.rc.i_aq_mode == X264_AQ_EXPERIMENTAL )
+        strength = h->param.rc.f_aq_strength * 0.5f;
+    else if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
     {
         for( mb_y = 0; mb_y < h->sps->i_mb_height; mb_y++ )
             for( mb_x = 0; mb_x < h->sps->i_mb_width; mb_x++ )
@@ -241,6 +244,7 @@ void x264_adaptive_quant_frame( x264_t *
             }
         avg_adj /= h->mb.i_mb_count;
         strength = h->param.rc.f_aq_strength * avg_adj * (1.f / 6000.f);
+        avg_offset = h->param.rc.f_aq_offset_strength * (avg_adj * avg_adj - 48000.f) * (1.f / 8000.f);
     }
     else
         strength = h->param.rc.f_aq_strength * 1.0397f;
@@ -249,10 +253,15 @@ void x264_adaptive_quant_frame( x264_t *
         for( mb_x = 0; mb_x < h->sps->i_mb_width; mb_x++ )
         {
             float qp_adj;
-            if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
+            if( h->param.rc.i_aq_mode == X264_AQ_EXPERIMENTAL )
+            {
+                int32_t energy = ac_energy_mb( h, mb_x, mb_y, frame );
+                qp_adj = strength * (powf( energy, 0.25f ) - 14.0f);
+            }
+            else if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
             {
                 qp_adj = frame->f_qp_offset[mb_x + mb_y*h->mb.i_mb_stride];
-                qp_adj = strength * (qp_adj - avg_adj);
+                qp_adj = strength * (qp_adj - avg_adj) + avg_offset;
             }
             else
             {
diff -uNrp a/x264.c b/x264.c
--- a/x264.c	2009-12-05 21:34:24 +0200
+++ b/x264.c	2009-12-05 22:18:09 +0200
@@ -238,9 +238,12 @@ static void Help( x264_param_t *defaults
     H2( "      --aq-mode <integer>     AQ method [%d]\n"
         "                                  - 0: Disabled\n"
         "                                  - 1: Variance AQ (complexity mask)\n"
-        "                                  - 2: Auto-variance AQ (experimental)\n", defaults->rc.i_aq_mode );
+        "                                  - 2: Auto-variance AQ (experimental)\n"
+        "                                  - 3: New experimental AQ\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 );
+        "                              textured areas. [%.1f]\n"
+        "                              (May present in #1:#2 form. Where #2 is frame QP offset.\n"
+        "                               Help with dark frames and fades. 1.0 is optimal)", defaults->rc.f_aq_strength );
     H1( "\n" );
     H2( "  -p, --pass <1|2|3>          Enable multipass ratecontrol\n" );
     else H0( "  -p, --pass <1|2>            Enable multipass ratecontrol\n" );
diff -uNrp a/x264.h b/x264.h
--- a/x264.h	2009-12-05 21:34:24 +0200
+++ b/x264.h	2009-12-05 22:18:36 +0200
@@ -92,6 +92,7 @@ typedef struct x264_t x264_t;
 #define X264_AQ_NONE                 0
 #define X264_AQ_VARIANCE             1
 #define X264_AQ_AUTOVARIANCE         2
+#define X264_AQ_EXPERIMENTAL         3
 #define X264_B_ADAPT_NONE            0
 #define X264_B_ADAPT_FAST            1
 #define X264_B_ADAPT_TRELLIS         2
@@ -286,6 +287,7 @@ typedef struct x264_param_t
 
         int         i_aq_mode;      /* psy adaptive QP. (X264_AQ_*) */
         float       f_aq_strength;
+        float       f_aq_offset_strength;
         int         b_mb_tree;      /* Macroblock-tree ratecontrol. */
         int         i_lookahead;