Add m-esr52 at 52.6.0

1 files changed, 583 insertions, 0 deletions

diff --git a/media/libvpx/vp8/encoder/quantize.c b/media/libvpx/vp8/encoder/quantize.c
new file mode 100644
index 000000000..c5a7bc670
--- /dev/null
+++ b/media/libvpx/vp8/encoder/quantize.c
@@ -0,0 +1,583 @@
+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#include <math.h>
+#include "vpx_mem/vpx_mem.h"
+
+#include "onyx_int.h"
+#include "quantize.h"
+#include "vp8/common/quant_common.h"
+
+void vp8_fast_quantize_b_c(BLOCK *b, BLOCKD *d)
+{
+    int i, rc, eob;
+    int x, y, z, sz;
+    short *coeff_ptr   = b->coeff;
+    short *round_ptr   = b->round;
+    short *quant_ptr   = b->quant_fast;
+    short *qcoeff_ptr  = d->qcoeff;
+    short *dqcoeff_ptr = d->dqcoeff;
+    short *dequant_ptr = d->dequant;
+
+    eob = -1;
+    for (i = 0; i < 16; i++)
+    {
+        rc   = vp8_default_zig_zag1d[i];
+        z    = coeff_ptr[rc];
+
+        sz = (z >> 31);                              /* sign of z */
+        x  = (z ^ sz) - sz;                          /* x = abs(z) */
+
+        y  = ((x + round_ptr[rc]) * quant_ptr[rc]) >> 16; /* 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 */
+
+        if (y)
+        {
+            eob = i;                                 /* last nonzero coeffs */
+        }
+    }
+    *d->eob = (char)(eob + 1);
+}
+
+void vp8_regular_quantize_b_c(BLOCK *b, BLOCKD *d)
+{
+    int i, rc, eob;
+    int zbin;
+    int x, y, z, sz;
+    short *zbin_boost_ptr  = b->zrun_zbin_boost;
+    short *coeff_ptr       = b->coeff;
+    short *zbin_ptr        = b->zbin;
+    short *round_ptr       = b->round;
+    short *quant_ptr       = b->quant;
+    short *quant_shift_ptr = b->quant_shift;
+    short *qcoeff_ptr      = d->qcoeff;
+    short *dqcoeff_ptr     = d->dqcoeff;
+    short *dequant_ptr     = d->dequant;
+    short zbin_oq_value    = b->zbin_extra;
+
+    memset(qcoeff_ptr, 0, 32);
+    memset(dqcoeff_ptr, 0, 32);
+
+    eob = -1;
+
+    for (i = 0; i < 16; i++)
+    {
+        rc   = vp8_default_zig_zag1d[i];
+        z    = coeff_ptr[rc];
+
+        zbin = zbin_ptr[rc] + *zbin_boost_ptr + zbin_oq_value;
+
+        zbin_boost_ptr ++;
+        sz = (z >> 31);                              /* sign of z */
+        x  = (z ^ sz) - sz;                          /* x = abs(z) */
+
+        if (x >= zbin)
+        {
+            x += round_ptr[rc];
+            y  = ((((x * quant_ptr[rc]) >> 16) + x)
+                 * quant_shift_ptr[rc]) >> 16;       /* 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 */
+
+            if (y)
+            {
+                eob = i;                             /* last nonzero coeffs */
+                zbin_boost_ptr = b->zrun_zbin_boost; /* reset zero runlength */
+            }
+        }
+    }
+
+    *d->eob = (char)(eob + 1);
+}
+
+void vp8_quantize_mby(MACROBLOCK *x)
+{
+    int i;
+    int has_2nd_order = (x->e_mbd.mode_info_context->mbmi.mode != B_PRED
+        && x->e_mbd.mode_info_context->mbmi.mode != SPLITMV);
+
+    for (i = 0; i < 16; i++)
+        x->quantize_b(&x->block[i], &x->e_mbd.block[i]);
+
+    if(has_2nd_order)
+        x->quantize_b(&x->block[24], &x->e_mbd.block[24]);
+}
+
+void vp8_quantize_mb(MACROBLOCK *x)
+{
+    int i;
+    int has_2nd_order=(x->e_mbd.mode_info_context->mbmi.mode != B_PRED
+        && x->e_mbd.mode_info_context->mbmi.mode != SPLITMV);
+
+    for (i = 0; i < 24+has_2nd_order; i++)
+        x->quantize_b(&x->block[i], &x->e_mbd.block[i]);
+}
+
+
+void vp8_quantize_mbuv(MACROBLOCK *x)
+{
+    int i;
+
+    for (i = 16; i < 24; i++)
+        x->quantize_b(&x->block[i], &x->e_mbd.block[i]);
+}
+
+static const int qrounding_factors[129] =
+{
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48
+};
+
+
+static const int qzbin_factors[129] =
+{
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80
+};
+
+
+static const int qrounding_factors_y2[129] =
+{
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48, 48, 48, 48, 48, 48, 48, 48,
+    48
+};
+
+
+static const int qzbin_factors_y2[129] =
+{
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    84, 84, 84, 84, 84, 84, 84, 84,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80, 80, 80, 80, 80, 80, 80, 80,
+    80
+};
+
+
+static void invert_quant(int improved_quant, short *quant,
+                         short *shift, short d)
+{
+    if(improved_quant)
+    {
+        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;
+        /* use multiplication and constant shift by 16 */
+        *shift = 1 << (16 - *shift);
+    }
+    else
+    {
+        *quant = (1 << 16) / d;
+        *shift = 0;
+        /* use multiplication and constant shift by 16 */
+        *shift = 1 << (16 - *shift);
+    }
+}
+
+
+void vp8cx_init_quantizer(VP8_COMP *cpi)
+{
+    int i;
+    int quant_val;
+    int Q;
+
+    int zbin_boost[16] = {0, 0, 8, 10, 12, 14, 16, 20, 24, 28, 32, 36, 40, 44,
+                          44, 44};
+
+    for (Q = 0; Q < QINDEX_RANGE; Q++)
+    {
+        /* dc values */
+        quant_val = vp8_dc_quant(Q, cpi->common.y1dc_delta_q);
+        cpi->Y1quant_fast[Q][0] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->Y1quant[Q] + 0,
+                     cpi->Y1quant_shift[Q] + 0, quant_val);
+        cpi->Y1zbin[Q][0] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
+        cpi->Y1round[Q][0] = (qrounding_factors[Q] * quant_val) >> 7;
+        cpi->common.Y1dequant[Q][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_fast[Q][0] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->Y2quant[Q] + 0,
+                     cpi->Y2quant_shift[Q] + 0, quant_val);
+        cpi->Y2zbin[Q][0] = ((qzbin_factors_y2[Q] * quant_val) + 64) >> 7;
+        cpi->Y2round[Q][0] = (qrounding_factors_y2[Q] * quant_val) >> 7;
+        cpi->common.Y2dequant[Q][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_fast[Q][0] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->UVquant[Q] + 0,
+                     cpi->UVquant_shift[Q] + 0, quant_val);
+        cpi->UVzbin[Q][0] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;;
+        cpi->UVround[Q][0] = (qrounding_factors[Q] * quant_val) >> 7;
+        cpi->common.UVdequant[Q][0] = quant_val;
+        cpi->zrun_zbin_boost_uv[Q][0] = (quant_val * zbin_boost[0]) >> 7;
+
+        /* all the ac values = ; */
+        quant_val = vp8_ac_yquant(Q);
+        cpi->Y1quant_fast[Q][1] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->Y1quant[Q] + 1,
+                     cpi->Y1quant_shift[Q] + 1, quant_val);
+        cpi->Y1zbin[Q][1] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
+        cpi->Y1round[Q][1] = (qrounding_factors[Q] * quant_val) >> 7;
+        cpi->common.Y1dequant[Q][1] = quant_val;
+        cpi->zrun_zbin_boost_y1[Q][1] = (quant_val * zbin_boost[1]) >> 7;
+
+        quant_val = vp8_ac2quant(Q, cpi->common.y2ac_delta_q);
+        cpi->Y2quant_fast[Q][1] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->Y2quant[Q] + 1,
+                     cpi->Y2quant_shift[Q] + 1, quant_val);
+        cpi->Y2zbin[Q][1] = ((qzbin_factors_y2[Q] * quant_val) + 64) >> 7;
+        cpi->Y2round[Q][1] = (qrounding_factors_y2[Q] * quant_val) >> 7;
+        cpi->common.Y2dequant[Q][1] = quant_val;
+        cpi->zrun_zbin_boost_y2[Q][1] = (quant_val * zbin_boost[1]) >> 7;
+
+        quant_val = vp8_ac_uv_quant(Q, cpi->common.uvac_delta_q);
+        cpi->UVquant_fast[Q][1] = (1 << 16) / quant_val;
+        invert_quant(cpi->sf.improved_quant, cpi->UVquant[Q] + 1,
+                     cpi->UVquant_shift[Q] + 1, quant_val);
+        cpi->UVzbin[Q][1] = ((qzbin_factors[Q] * quant_val) + 64) >> 7;
+        cpi->UVround[Q][1] = (qrounding_factors[Q] * quant_val) >> 7;
+        cpi->common.UVdequant[Q][1] = quant_val;
+        cpi->zrun_zbin_boost_uv[Q][1] = (quant_val * zbin_boost[1]) >> 7;
+
+        for (i = 2; i < 16; i++)
+        {
+            cpi->Y1quant_fast[Q][i] = cpi->Y1quant_fast[Q][1];
+            cpi->Y1quant[Q][i] = cpi->Y1quant[Q][1];
+            cpi->Y1quant_shift[Q][i] = cpi->Y1quant_shift[Q][1];
+            cpi->Y1zbin[Q][i] = cpi->Y1zbin[Q][1];
+            cpi->Y1round[Q][i] = cpi->Y1round[Q][1];
+            cpi->zrun_zbin_boost_y1[Q][i] = (cpi->common.Y1dequant[Q][1] *
+                                             zbin_boost[i]) >> 7;
+
+            cpi->Y2quant_fast[Q][i] = cpi->Y2quant_fast[Q][1];
+            cpi->Y2quant[Q][i] = cpi->Y2quant[Q][1];
+            cpi->Y2quant_shift[Q][i] = cpi->Y2quant_shift[Q][1];
+            cpi->Y2zbin[Q][i] = cpi->Y2zbin[Q][1];
+            cpi->Y2round[Q][i] = cpi->Y2round[Q][1];
+            cpi->zrun_zbin_boost_y2[Q][i] = (cpi->common.Y2dequant[Q][1] *
+                                             zbin_boost[i]) >> 7;
+
+            cpi->UVquant_fast[Q][i] = cpi->UVquant_fast[Q][1];
+            cpi->UVquant[Q][i] = cpi->UVquant[Q][1];
+            cpi->UVquant_shift[Q][i] = cpi->UVquant_shift[Q][1];
+            cpi->UVzbin[Q][i] = cpi->UVzbin[Q][1];
+            cpi->UVround[Q][i] = cpi->UVround[Q][1];
+            cpi->zrun_zbin_boost_uv[Q][i] = (cpi->common.UVdequant[Q][1] *
+                                             zbin_boost[i]) >> 7;
+        }
+    }
+}
+
+#define ZBIN_EXTRA_Y \
+    (( cpi->common.Y1dequant[QIndex][1] *  \
+    ( x->zbin_over_quant +  \
+      x->zbin_mode_boost +  \
+      x->act_zbin_adj ) ) >> 7)
+
+#define ZBIN_EXTRA_UV \
+    (( cpi->common.UVdequant[QIndex][1] *  \
+    ( x->zbin_over_quant +  \
+      x->zbin_mode_boost +  \
+      x->act_zbin_adj ) ) >> 7)
+
+#define ZBIN_EXTRA_Y2 \
+    (( cpi->common.Y2dequant[QIndex][1] *  \
+    ( (x->zbin_over_quant / 2) +  \
+       x->zbin_mode_boost +  \
+       x->act_zbin_adj ) ) >> 7)
+
+void vp8cx_mb_init_quantizer(VP8_COMP *cpi, MACROBLOCK *x, int ok_to_skip)
+{
+    int i;
+    int QIndex;
+    MACROBLOCKD *xd = &x->e_mbd;
+    int zbin_extra;
+
+    /* Select the baseline MB Q index. */
+    if (xd->segmentation_enabled)
+    {
+        /* Abs Value */
+        if (xd->mb_segement_abs_delta == SEGMENT_ABSDATA)
+            QIndex = xd->segment_feature_data[MB_LVL_ALT_Q][xd->mode_info_context->mbmi.segment_id];
+        /* Delta Value */
+        else
+        {
+            QIndex = cpi->common.base_qindex + xd->segment_feature_data[MB_LVL_ALT_Q][xd->mode_info_context->mbmi.segment_id];
+            /* Clamp to valid range */
+            QIndex = (QIndex >= 0) ? ((QIndex <= MAXQ) ? QIndex : MAXQ) : 0;
+        }
+    }
+    else
+        QIndex = cpi->common.base_qindex;
+
+    /* This initialization should be called at least once. Use ok_to_skip to
+     * decide if it is ok to skip.
+     * Before encoding a frame, this function is always called with ok_to_skip
+     * =0, which means no skiping of calculations. The "last" values are
+     * initialized at that time.
+     */
+    if (!ok_to_skip || QIndex != x->q_index)
+    {
+
+        xd->dequant_y1_dc[0] = 1;
+        xd->dequant_y1[0] = cpi->common.Y1dequant[QIndex][0];
+        xd->dequant_y2[0] = cpi->common.Y2dequant[QIndex][0];
+        xd->dequant_uv[0] = cpi->common.UVdequant[QIndex][0];
+
+        for (i = 1; i < 16; i++)
+        {
+            xd->dequant_y1_dc[i] =
+            xd->dequant_y1[i] = cpi->common.Y1dequant[QIndex][1];
+            xd->dequant_y2[i] = cpi->common.Y2dequant[QIndex][1];
+            xd->dequant_uv[i] = cpi->common.UVdequant[QIndex][1];
+        }
+#if 1
+        /*TODO:  Remove dequant from BLOCKD.  This is a temporary solution until
+         * the quantizer code uses a passed in pointer to the dequant constants.
+         * This will also require modifications to the x86 and neon assembly.
+         * */
+        for (i = 0; i < 16; i++)
+            x->e_mbd.block[i].dequant = xd->dequant_y1;
+        for (i = 16; i < 24; i++)
+            x->e_mbd.block[i].dequant = xd->dequant_uv;
+        x->e_mbd.block[24].dequant = xd->dequant_y2;
+#endif
+
+        /* Y */
+        zbin_extra = ZBIN_EXTRA_Y;
+
+        for (i = 0; i < 16; i++)
+        {
+            x->block[i].quant = cpi->Y1quant[QIndex];
+            x->block[i].quant_fast = cpi->Y1quant_fast[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->block[i].zrun_zbin_boost = cpi->zrun_zbin_boost_y1[QIndex];
+            x->block[i].zbin_extra = (short)zbin_extra;
+        }
+
+        /* UV */
+        zbin_extra = ZBIN_EXTRA_UV;
+
+        for (i = 16; i < 24; i++)
+        {
+            x->block[i].quant = cpi->UVquant[QIndex];
+            x->block[i].quant_fast = cpi->UVquant_fast[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->block[i].zrun_zbin_boost = cpi->zrun_zbin_boost_uv[QIndex];
+            x->block[i].zbin_extra = (short)zbin_extra;
+        }
+
+        /* Y2 */
+        zbin_extra = ZBIN_EXTRA_Y2;
+
+        x->block[24].quant_fast = cpi->Y2quant_fast[QIndex];
+        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->block[24].zrun_zbin_boost = cpi->zrun_zbin_boost_y2[QIndex];
+        x->block[24].zbin_extra = (short)zbin_extra;
+
+        /* save this macroblock QIndex for vp8_update_zbin_extra() */
+        x->q_index = QIndex;
+
+        x->last_zbin_over_quant = x->zbin_over_quant;
+        x->last_zbin_mode_boost = x->zbin_mode_boost;
+        x->last_act_zbin_adj = x->act_zbin_adj;
+
+
+
+    }
+    else if(x->last_zbin_over_quant != x->zbin_over_quant
+            || x->last_zbin_mode_boost != x->zbin_mode_boost
+            || x->last_act_zbin_adj != x->act_zbin_adj)
+    {
+        /* Y */
+        zbin_extra = ZBIN_EXTRA_Y;
+
+        for (i = 0; i < 16; i++)
+            x->block[i].zbin_extra = (short)zbin_extra;
+
+        /* UV */
+        zbin_extra = ZBIN_EXTRA_UV;
+
+        for (i = 16; i < 24; i++)
+            x->block[i].zbin_extra = (short)zbin_extra;
+
+        /* Y2 */
+        zbin_extra = ZBIN_EXTRA_Y2;
+        x->block[24].zbin_extra = (short)zbin_extra;
+
+        x->last_zbin_over_quant = x->zbin_over_quant;
+        x->last_zbin_mode_boost = x->zbin_mode_boost;
+        x->last_act_zbin_adj = x->act_zbin_adj;
+    }
+}
+
+void vp8_update_zbin_extra(VP8_COMP *cpi, MACROBLOCK *x)
+{
+    int i;
+    int QIndex = x->q_index;
+    int zbin_extra;
+
+    /* Y */
+    zbin_extra = ZBIN_EXTRA_Y;
+
+    for (i = 0; i < 16; i++)
+        x->block[i].zbin_extra = (short)zbin_extra;
+
+    /* UV */
+    zbin_extra = ZBIN_EXTRA_UV;
+
+    for (i = 16; i < 24; i++)
+        x->block[i].zbin_extra = (short)zbin_extra;
+
+    /* Y2 */
+    zbin_extra = ZBIN_EXTRA_Y2;
+    x->block[24].zbin_extra = (short)zbin_extra;
+}
+#undef ZBIN_EXTRA_Y
+#undef ZBIN_EXTRA_UV
+#undef ZBIN_EXTRA_Y2
+
+void vp8cx_frame_init_quantizer(VP8_COMP *cpi)
+{
+    /* Clear Zbin mode boost for default case */
+    cpi->mb.zbin_mode_boost = 0;
+
+    /* MB level quantizer setup */
+    vp8cx_mb_init_quantizer(cpi, &cpi->mb, 0);
+}
+
+
+void vp8_set_quantizer(struct VP8_COMP *cpi, int Q)
+{
+    VP8_COMMON *cm = &cpi->common;
+    MACROBLOCKD *mbd = &cpi->mb.e_mbd;
+    int update = 0;
+    int new_delta_q;
+    int new_uv_delta_q;
+    cm->base_qindex = Q;
+
+    /* if any of the delta_q values are changing update flag has to be set */
+    /* currently only y2dc_delta_q may change */
+
+    cm->y1dc_delta_q = 0;
+    cm->y2ac_delta_q = 0;
+
+    if (Q < 4)
+    {
+        new_delta_q = 4-Q;
+    }
+    else
+        new_delta_q = 0;
+
+    update |= cm->y2dc_delta_q != new_delta_q;
+    cm->y2dc_delta_q = new_delta_q;
+
+    new_uv_delta_q = 0;
+    // For screen content, lower the q value for UV channel. For now, select
+    // conservative delta; same delta for dc and ac, and decrease it with lower
+    // Q, and set to 0 below some threshold. May want to condition this in
+    // future on the variance/energy in UV channel.
+    if (cpi->oxcf.screen_content_mode && Q > 40) {
+      new_uv_delta_q = -(int)(0.15 * Q);
+      // Check range: magnitude of delta is 4 bits.
+      if (new_uv_delta_q < -15) {
+        new_uv_delta_q = -15;
+      }
+    }
+    update |= cm->uvdc_delta_q != new_uv_delta_q;
+    cm->uvdc_delta_q = new_uv_delta_q;
+    cm->uvac_delta_q = new_uv_delta_q;
+
+    /* Set Segment specific quatizers */
+    mbd->segment_feature_data[MB_LVL_ALT_Q][0] = cpi->segment_feature_data[MB_LVL_ALT_Q][0];
+    mbd->segment_feature_data[MB_LVL_ALT_Q][1] = cpi->segment_feature_data[MB_LVL_ALT_Q][1];
+    mbd->segment_feature_data[MB_LVL_ALT_Q][2] = cpi->segment_feature_data[MB_LVL_ALT_Q][2];
+    mbd->segment_feature_data[MB_LVL_ALT_Q][3] = cpi->segment_feature_data[MB_LVL_ALT_Q][3];
+
+    /* quantizer has to be reinitialized for any delta_q changes */
+    if(update)
+        vp8cx_init_quantizer(cpi);
+
+}