Make the quantizer exact.

This replaces the approximate division-by-multiplication in the
 quantizer with an exact one that costs just one add and one
 shift extra.
The asm versions have not been updated in this patch, and thus
 have been disabled, since the new method requires different
 multipliers which are not compatible with the old method.

Change-Id: I53ac887af0f969d906e464c88b1f4be69c6b1206

diff --git a/vp8/encoder/arm/csystemdependent.c b/vp8/encoder/arm/csystemdependent.c
index 4521bfc..bfceab1 100644 (file)
--- a/vp8/encoder/arm/csystemdependent.c
+++ b/vp8/encoder/arm/csystemdependent.c
@@ -63,7 +63,7 @@ void vp8_cmachine_specific_config(VP8_COMP *cpi)
     cpi->rtcd.encodemb.submbuv               = vp8_subtract_mbuv_neon;
 
     cpi->rtcd.quantize.quantb                = vp8_regular_quantize_b;
-    cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_neon;
+    /*cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_neon;*/
 #elif HAVE_ARMV6
     cpi->rtcd.variance.sad16x16              = vp8_sad16x16_c;
     cpi->rtcd.variance.sad16x8               = vp8_sad16x8_c;

diff --git a/vp8/encoder/block.h b/vp8/encoder/block.h
index b55bc51..19d307d 100644 (file)
--- a/vp8/encoder/block.h
+++ b/vp8/encoder/block.h
@@ -33,6 +33,7 @@ typedef struct
 
     // 16 Y blocks, 4 U blocks, 4 V blocks each with 16 entries
     short(*quant)[4];
+    short(*quant_shift)[4];
     short(*zbin)[4];
     short(*zrun_zbin_boost);
     short(*round)[4];

diff --git a/vp8/encoder/encodeframe.c b/vp8/encoder/encodeframe.c
index 32cef1d..a05b332 100644 (file)
--- a/vp8/encoder/encodeframe.c
+++ b/vp8/encoder/encodeframe.c
@@ -103,6 +103,18 @@ static const int qzbin_factors[129] =
     80,
 };
 
+static void vp8cx_invert_quant(short *quant, short *shift, short d)
+{
+    unsigned t;
+    int l;
+    t = d;
+    for(l = 0; t > 1; l++)
+        t>>=1;
+    t = 1 + (1<<(16+l))/d;
+    *quant = (short)(t - (1<<16));
+    *shift = l;
+}
+
 void vp8cx_init_quantizer(VP8_COMP *cpi)
 {
     int r, c;
@@ -116,21 +128,24 @@ void vp8cx_init_quantizer(VP8_COMP *cpi)
     {
         // dc values
         quant_val = vp8_dc_quant(Q, cpi->common.y1dc_delta_q);
-        cpi->Y1quant[Q][0][0] = (1 << 16) / quant_val;
+        vp8cx_invert_quant(cpi->Y1quant[Q][0] + 0,
+                           cpi->Y1quant_shift[Q][0] + 0, quant_val);
         cpi->Y1zbin[Q][0][0] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
         cpi->Y1round[Q][0][0] = (qrounding_factors[Q] * quant_val) >> 7;
         cpi->common.Y1dequant[Q][0][0] = quant_val;
         cpi->zrun_zbin_boost_y1[Q][0] = (quant_val * zbin_boost[0]) >> 7;
 
         quant_val = vp8_dc2quant(Q, cpi->common.y2dc_delta_q);
-        cpi->Y2quant[Q][0][0] = (1 << 16) / quant_val;
+        vp8cx_invert_quant(cpi->Y2quant[Q][0] + 0,
+                           cpi->Y2quant_shift[Q][0] + 0, quant_val);
         cpi->Y2zbin[Q][0][0] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
         cpi->Y2round[Q][0][0] = (qrounding_factors[Q] * quant_val) >> 7;
         cpi->common.Y2dequant[Q][0][0] = quant_val;
         cpi->zrun_zbin_boost_y2[Q][0] = (quant_val * zbin_boost[0]) >> 7;
 
         quant_val = vp8_dc_uv_quant(Q, cpi->common.uvdc_delta_q);
-        cpi->UVquant[Q][0][0] = (1 << 16) / quant_val;
+        vp8cx_invert_quant(cpi->UVquant[Q][0] + 0,
+                           cpi->UVquant_shift[Q][0] + 0, quant_val);
         cpi->UVzbin[Q][0][0] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;;
         cpi->UVround[Q][0][0] = (qrounding_factors[Q] * quant_val) >> 7;
         cpi->common.UVdequant[Q][0][0] = quant_val;
@@ -144,21 +159,24 @@ void vp8cx_init_quantizer(VP8_COMP *cpi)
             c = (rc & 3);
 
             quant_val = vp8_ac_yquant(Q);
-            cpi->Y1quant[Q][r][c] = (1 << 16) / quant_val;
+            vp8cx_invert_quant(cpi->Y1quant[Q][r] + c,
+                               cpi->Y1quant_shift[Q][r] + c, quant_val);
             cpi->Y1zbin[Q][r][c] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
             cpi->Y1round[Q][r][c] = (qrounding_factors[Q] * quant_val) >> 7;
             cpi->common.Y1dequant[Q][r][c] = quant_val;
             cpi->zrun_zbin_boost_y1[Q][i] = (quant_val * zbin_boost[i]) >> 7;
 
             quant_val = vp8_ac2quant(Q, cpi->common.y2ac_delta_q);
-            cpi->Y2quant[Q][r][c] = (1 << 16) / quant_val;
+            vp8cx_invert_quant(cpi->Y2quant[Q][r] + c,
+                               cpi->Y2quant_shift[Q][r] + c, quant_val);
             cpi->Y2zbin[Q][r][c] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
             cpi->Y2round[Q][r][c] = (qrounding_factors[Q] * quant_val) >> 7;
             cpi->common.Y2dequant[Q][r][c] = quant_val;
             cpi->zrun_zbin_boost_y2[Q][i] = (quant_val * zbin_boost[i]) >> 7;
 
             quant_val = vp8_ac_uv_quant(Q, cpi->common.uvac_delta_q);
-            cpi->UVquant[Q][r][c] = (1 << 16) / quant_val;
+            vp8cx_invert_quant(cpi->UVquant[Q][r] + c,
+                               cpi->UVquant_shift[Q][r] + c, quant_val);
             cpi->UVzbin[Q][r][c] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
             cpi->UVround[Q][r][c] = (qrounding_factors[Q] * quant_val) >> 7;
             cpi->common.UVdequant[Q][r][c] = quant_val;
@@ -198,6 +216,7 @@ void vp8cx_mb_init_quantizer(VP8_COMP *cpi, MACROBLOCK *x)
     for (i = 0; i < 16; i++)
     {
         x->block[i].quant = cpi->Y1quant[QIndex];
+        x->block[i].quant_shift = cpi->Y1quant_shift[QIndex];
         x->block[i].zbin = cpi->Y1zbin[QIndex];
         x->block[i].round = cpi->Y1round[QIndex];
         x->e_mbd.block[i].dequant = cpi->common.Y1dequant[QIndex];
@@ -211,6 +230,7 @@ void vp8cx_mb_init_quantizer(VP8_COMP *cpi, MACROBLOCK *x)
     for (i = 16; i < 24; i++)
     {
         x->block[i].quant = cpi->UVquant[QIndex];
+        x->block[i].quant_shift = cpi->UVquant_shift[QIndex];
         x->block[i].zbin = cpi->UVzbin[QIndex];
         x->block[i].round = cpi->UVround[QIndex];
         x->e_mbd.block[i].dequant = cpi->common.UVdequant[QIndex];
@@ -221,6 +241,7 @@ void vp8cx_mb_init_quantizer(VP8_COMP *cpi, MACROBLOCK *x)
     // Y2
     zbin_extra = (cpi->common.Y2dequant[QIndex][0][1] * ((cpi->zbin_over_quant / 2) + cpi->zbin_mode_boost)) >> 7;
     x->block[24].quant = cpi->Y2quant[QIndex];
+    x->block[24].quant_shift = cpi->Y2quant_shift[QIndex];
     x->block[24].zbin = cpi->Y2zbin[QIndex];
     x->block[24].round = cpi->Y2round[QIndex];
     x->e_mbd.block[24].dequant = cpi->common.Y2dequant[QIndex];

diff --git a/vp8/encoder/ethreading.c b/vp8/encoder/ethreading.c
index dd98a09..54646f4 100644 (file)
--- a/vp8/encoder/ethreading.c
+++ b/vp8/encoder/ethreading.c
@@ -286,6 +286,7 @@ static void setup_mbby_copy(MACROBLOCK *mbdst, MACROBLOCK *mbsrc)
     for (i = 0; i < 25; i++)
     {
         z->block[i].quant           = x->block[i].quant;
+        z->block[i].quant_shift     = x->block[i].quant_shift;
         z->block[i].zbin            = x->block[i].zbin;
         z->block[i].zrun_zbin_boost   = x->block[i].zrun_zbin_boost;
         z->block[i].round           = x->block[i].round;

diff --git a/vp8/encoder/onyx_int.h b/vp8/encoder/onyx_int.h
index fcde220..f76d2ef 100644 (file)
--- a/vp8/encoder/onyx_int.h
+++ b/vp8/encoder/onyx_int.h
@@ -234,14 +234,17 @@ typedef struct
 {
 
     DECLARE_ALIGNED(16, short, Y1quant[QINDEX_RANGE][4][4]);
+    DECLARE_ALIGNED(16, short, Y1quant_shift[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, Y1zbin[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, Y1round[QINDEX_RANGE][4][4]);
 
     DECLARE_ALIGNED(16, short, Y2quant[QINDEX_RANGE][4][4]);
+    DECLARE_ALIGNED(16, short, Y2quant_shift[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, Y2zbin[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, Y2round[QINDEX_RANGE][4][4]);
 
     DECLARE_ALIGNED(16, short, UVquant[QINDEX_RANGE][4][4]);
+    DECLARE_ALIGNED(16, short, UVquant_shift[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, UVzbin[QINDEX_RANGE][4][4]);
     DECLARE_ALIGNED(16, short, UVround[QINDEX_RANGE][4][4]);
 

diff --git a/vp8/encoder/quantize.c b/vp8/encoder/quantize.c
index 181870c..877002b 100644 (file)
--- a/vp8/encoder/quantize.c
+++ b/vp8/encoder/quantize.c
@@ -25,6 +25,7 @@ void vp8_fast_quantize_b_c(BLOCK *b, BLOCKD *d)
     short *zbin_ptr   = &b->zbin[0][0];
     short *round_ptr  = &b->round[0][0];
     short *quant_ptr  = &b->quant[0][0];
+    short *quant_shift_ptr = &b->quant_shift[0][0];
     short *qcoeff_ptr = d->qcoeff;
     short *dqcoeff_ptr = d->dqcoeff;
     short *dequant_ptr = &d->dequant[0][0];
@@ -45,7 +46,9 @@ void vp8_fast_quantize_b_c(BLOCK *b, BLOCKD *d)
 
         if (x >= zbin)
         {
-            y  = ((x + round_ptr[rc]) * quant_ptr[rc]) >> 16; // quantize (x)
+            x += round_ptr[rc];
+            y  = (((x * quant_ptr[rc]) >> 16) + x)
+                 >> quant_shift_ptr[rc];                // quantize (x)
             x  = (y ^ sz) - sz;                         // get the sign back
             qcoeff_ptr[rc] = x;                          // write to destination
             dqcoeff_ptr[rc] = x * dequant_ptr[rc];        // dequantized value
@@ -69,6 +72,7 @@ void vp8_regular_quantize_b(BLOCK *b, BLOCKD *d)
     short *zbin_ptr   = &b->zbin[0][0];
     short *round_ptr  = &b->round[0][0];
     short *quant_ptr  = &b->quant[0][0];
+    short *quant_shift_ptr = &b->quant_shift[0][0];
     short *qcoeff_ptr = d->qcoeff;
     short *dqcoeff_ptr = d->dqcoeff;
     short *dequant_ptr = &d->dequant[0][0];
@@ -95,7 +99,9 @@ void vp8_regular_quantize_b(BLOCK *b, BLOCKD *d)
 
         if (x >= zbin)
         {
-            y  = ((x + round_ptr[rc]) * quant_ptr[rc]) >> 16; // quantize (x)
+            x += round_ptr[rc];
+            y  = (((x * quant_ptr[rc]) >> 16) + x)
+                 >> quant_shift_ptr[rc];                // quantize (x)
             x  = (y ^ sz) - sz;                         // get the sign back
             qcoeff_ptr[rc]  = x;                         // write to destination
             dqcoeff_ptr[rc] = x * dequant_ptr[rc];        // dequantized value

diff --git a/vp8/encoder/x86/x86_csystemdependent.c b/vp8/encoder/x86/x86_csystemdependent.c
index 11ef419..be226e0 100644 (file)
--- a/vp8/encoder/x86/x86_csystemdependent.c
+++ b/vp8/encoder/x86/x86_csystemdependent.c
@@ -238,7 +238,7 @@ void vp8_arch_x86_encoder_init(VP8_COMP *cpi)
         cpi->rtcd.encodemb.submby                = vp8_subtract_mby_mmx;
         cpi->rtcd.encodemb.submbuv               = vp8_subtract_mbuv_mmx;
 
-        cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_mmx;
+        /*cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_mmx;*/
     }
 
 #endif
@@ -285,8 +285,8 @@ void vp8_arch_x86_encoder_init(VP8_COMP *cpi)
         cpi->rtcd.encodemb.mbuverr               = vp8_mbuverror_xmm;
         /* cpi->rtcd.encodemb.sub* not implemented for wmt */
 
-        cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_sse;
-        cpi->rtcd.quantize.quantb            = vp8_regular_quantize_b_sse2;
+        /*cpi->rtcd.quantize.fastquantb            = vp8_fast_quantize_b_sse;
+        cpi->rtcd.quantize.quantb            = vp8_regular_quantize_b_sse2;*/
     }
 
 #endif