shithub: libvpx

Download patch

ref: 8002c318041d83ee44321e76972c7a30753024b7
parent: 63bf108731fdf60dcce91aa6e9e6d27b56199011
parent: 88e24f07aed48593f455db9839cdf792c858f4d7
author: Yaowu Xu <yaowu@google.com>
date: Wed Nov 2 04:22:58 EDT 2011 

Merge "added code to clear 2nd order block when appropriate"


--- a/vp8/encoder/encodeintra.c
+++ b/vp8/encoder/encodeintra.c
@@ -94,7 +94,8 @@
 
     RECON_INVOKE(&rtcd->common->recon, build_intra_predictors_mby)(&x->e_mbd);
 
-    ENCODEMB_INVOKE(&rtcd->encodemb, submby)(x->src_diff, *(b->base_src), x->e_mbd.predictor, b->src_stride);
+    ENCODEMB_INVOKE(&rtcd->encodemb, submby)(x->src_diff, *(b->base_src),
+        x->e_mbd.predictor, b->src_stride);
 
     vp8_transform_intra_mby(x);
 
--- a/vp8/encoder/encodemb.c
+++ b/vp8/encoder/encodemb.c
@@ -469,12 +469,50 @@
     d->eob = final_eob;
     *a = *l = (d->eob != !type);
 }
+static void check_reset_2nd_coeffs(MACROBLOCKD *x, int type,
+                                   ENTROPY_CONTEXT *a, ENTROPY_CONTEXT *l)
+{
+    int sum=0;
+    int i;
+    BLOCKD *bd = &x->block[24];
 
+    if(bd->dequant[0]>=35 && bd->dequant[1]>=35)
+        return;
+
+    for(i=0;i<bd->eob;i++)
+    {
+        int coef = bd->dqcoeff[vp8_default_zig_zag1d[i]];
+        sum+= (coef>=0)?coef:-coef;
+        if(sum>=35)
+            return;
+    }
+    /**************************************************************************
+    our inverse hadamard transform effectively is weighted sum of all 16 inputs
+    with weight either 1 or -1. It has a last stage scaling of (sum+3)>>3. And
+    dc only idct is (dc+4)>>3. So if all the sums are between -35 and 29, the
+    output after inverse wht and idct will be all zero. A sum of absolute value
+    smaller than 35 guarantees all 16 different (+1/-1) weighted sums in wht
+    fall between -35 and +35.
+    **************************************************************************/
+    if(sum < 35)
+    {
+        for(i=0;i<bd->eob;i++)
+        {
+            int rc = vp8_default_zig_zag1d[i];
+            bd->qcoeff[rc]=0;
+            bd->dqcoeff[rc]=0;
+        }
+        bd->eob = 0;
+        *a = *l = (bd->eob != !type);
+    }
+}
+
 static void optimize_mb(MACROBLOCK *x, const VP8_ENCODER_RTCD *rtcd)
 {
     int b;
     int type;
     int has_2nd_order;
+
     ENTROPY_CONTEXT_PLANES t_above, t_left;
     ENTROPY_CONTEXT *ta;
     ENTROPY_CONTEXT *tl;
@@ -506,6 +544,8 @@
         b=24;
         optimize_b(x, b, PLANE_TYPE_Y2,
             ta + vp8_block2above[b], tl + vp8_block2left[b], rtcd);
+        check_reset_2nd_coeffs(&x->e_mbd, PLANE_TYPE_Y2,
+            ta + vp8_block2above[b], tl + vp8_block2left[b]);
     }
 }
 
@@ -539,7 +579,7 @@
     for (b = 0; b < 16; b++)
     {
         optimize_b(x, b, type,
-        ta + vp8_block2above[b], tl + vp8_block2left[b], rtcd);
+            ta + vp8_block2above[b], tl + vp8_block2left[b], rtcd);
     }
 
 
@@ -548,6 +588,8 @@
         b=24;
         optimize_b(x, b, PLANE_TYPE_Y2,
             ta + vp8_block2above[b], tl + vp8_block2left[b], rtcd);
+        check_reset_2nd_coeffs(&x->e_mbd, PLANE_TYPE_Y2,
+            ta + vp8_block2above[b], tl + vp8_block2left[b]);
     }
 }
 
-- 
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