diff --git a/encoder/encoder.c b/encoder/encoder.c
index 4188baf..f07cc0e 100644
--- a/encoder/encoder.c
+++ b/encoder/encoder.c
@@ -548,7 +548,7 @@ static int x264_validate_parameters( x264_t *h )
     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.i_aq_mode = x264_clip3( h->param.rc.i_aq_mode, 0, 3 );
     h->param.rc.f_aq_strength = x264_clip3f( h->param.rc.f_aq_strength, 0, 3 );
     if( h->param.rc.f_aq_strength == 0 )
         h->param.rc.i_aq_mode = 0;
diff --git a/encoder/ratecontrol.c b/encoder/ratecontrol.c
index 99831a6..442bbc9 100644
--- a/encoder/ratecontrol.c
+++ b/encoder/ratecontrol.c
@@ -204,6 +204,7 @@ void x264_adaptive_quant_frame( x264_t *h, x264_frame_t *frame )
     int mb_x, mb_y;
     float strength;
     float avg_adj = 0.f;
+    float avg_offset = 0.f;
     /* Need to init it anyways for MB tree. */
     if( h->param.rc.f_aq_strength == 0 )
     {
@@ -215,7 +216,7 @@ void x264_adaptive_quant_frame( x264_t *h, x264_frame_t *frame )
         return;
     }
 
-    if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
+    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++ )
@@ -228,6 +229,8 @@ void x264_adaptive_quant_frame( x264_t *h, x264_frame_t *frame )
             }
         avg_adj /= h->mb.i_mb_count;
         strength = h->param.rc.f_aq_strength * avg_adj * (1.f / 6000.f);
+        if( h->param.rc.i_aq_mode > X264_AQ_AUTOVARIANCE )
+            avg_offset = h->param.rc.f_aq_strength * (avg_adj * avg_adj - 48000.f) * (1.f / 8000.f);
     }
     else
         strength = h->param.rc.f_aq_strength * 1.0397f;
@@ -236,10 +239,10 @@ void x264_adaptive_quant_frame( x264_t *h, x264_frame_t *frame )
         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_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
             {