/*

 * Copyright (c) 2016, Alliance for Open Media. All rights reserved.

 *

 * This source code is subject to the terms of the BSD 2 Clause License and

 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License

 * was not distributed with this source code in the LICENSE file, you can

 * obtain it at www.aomedia.org/license/software. If the Alliance for Open

 * Media Patent License 1.0 was not distributed with this source code in the

 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.

 */

#include <math.h>

#include "config/aom_dsp_rtcd.h"

#include "aom/aomcx.h"

#include "aom_dsp/quantize.h"

#include "aom_mem/aom_mem.h"

#include "aom_ports/bitops.h"

#include "aom_ports/mem.h"

#include "av1/common/idct.h"

#include "av1/common/quant_common.h"

#include "av1/common/scan.h"

#include "av1/common/seg_common.h"

#include "av1/encoder/av1_quantize.h"

#include "av1/encoder/encoder.h"

#include "av1/encoder/rd.h"

void av1_quantize_skip(intptr_t n_coeffs, tran_low_t *qcoeff_ptr,

                       tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr) {

  memset(qcoeff_ptr, 0, n_coeffs * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, n_coeffs * sizeof(*dqcoeff_ptr));

  *eob_ptr = 0;

}

int av1_quantize_fp_no_qmatrix(const int16_t quant_ptr[2],

                               const int16_t dequant_ptr[2],

                               const int16_t round_ptr[2], int log_scale,

                               const int16_t *scan, int coeff_count,

                               const tran_low_t *coeff_ptr,

                               tran_low_t *qcoeff_ptr,

                               tran_low_t *dqcoeff_ptr) {

  memset(qcoeff_ptr, 0, coeff_count * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, coeff_count * sizeof(*dqcoeff_ptr));

  const int rounding[2] = { ROUND_POWER_OF_TWO(round_ptr[0], log_scale),

                            ROUND_POWER_OF_TWO(round_ptr[1], log_scale) };

  int eob = 0;

  for (int i = 0; i < coeff_count; i++) {

    const int rc = scan[i];

    const int32_t thresh = (int32_t)(dequant_ptr[rc != 0]);

    const int coeff = coeff_ptr[rc];

    const int coeff_sign = AOMSIGN(coeff);

    int64_t abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

    int tmp32 = 0;

    if ((abs_coeff << (1 + log_scale)) >= thresh) {

      abs_coeff = clamp64(abs_coeff + rounding[rc != 0], INT16_MIN, INT16_MAX);

      tmp32 = (int)((abs_coeff * quant_ptr[rc != 0]) >> (16 - log_scale));

      if (tmp32) {

        qcoeff_ptr[rc] = (tmp32 ^ coeff_sign) - coeff_sign;

        const tran_low_t abs_dqcoeff =

            (tmp32 * dequant_ptr[rc != 0]) >> log_scale;

        dqcoeff_ptr[rc] = (abs_dqcoeff ^ coeff_sign) - coeff_sign;

      }

    }

    if (tmp32) eob = i + 1;

  }

  return eob;

}

static void quantize_fp_helper_c(

    const tran_low_t *coeff_ptr, intptr_t n_coeffs, const int16_t *zbin_ptr,

    const int16_t *round_ptr, const int16_t *quant_ptr,

    const int16_t *quant_shift_ptr, tran_low_t *qcoeff_ptr,

    tran_low_t *dqcoeff_ptr, const int16_t *dequant_ptr, uint16_t *eob_ptr,

    const int16_t *scan, const int16_t *iscan, const qm_val_t *qm_ptr,

    const qm_val_t *iqm_ptr, int log_scale) {

  int i, eob = -1;

  const int rounding[2] = { ROUND_POWER_OF_TWO(round_ptr[0], log_scale),

                            ROUND_POWER_OF_TWO(round_ptr[1], log_scale) };

  // TODO(jingning) Decide the need of these arguments after the

  // quantization process is completed.

  (void)zbin_ptr;

  (void)quant_shift_ptr;

  (void)iscan;

  memset(qcoeff_ptr, 0, n_coeffs * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, n_coeffs * sizeof(*dqcoeff_ptr));

  if (qm_ptr == NULL && iqm_ptr == NULL) {

    *eob_ptr = av1_quantize_fp_no_qmatrix(quant_ptr, dequant_ptr, round_ptr,

                                          log_scale, scan, (int)n_coeffs,

                                          coeff_ptr, qcoeff_ptr, dqcoeff_ptr);

  } else {

    // Quantization pass: All coefficients with index >= zero_flag are

    // skippable. Note: zero_flag can be zero.

    for (i = 0; i < n_coeffs; i++) {

      const int rc = scan[i];

      const int coeff = coeff_ptr[rc];

      const qm_val_t wt = qm_ptr ? qm_ptr[rc] : (1 << AOM_QM_BITS);

      const qm_val_t iwt = iqm_ptr ? iqm_ptr[rc] : (1 << AOM_QM_BITS);

      const int dequant =

          (dequant_ptr[rc != 0] * iwt + (1 << (AOM_QM_BITS - 1))) >>

          AOM_QM_BITS;

      const int coeff_sign = AOMSIGN(coeff);

      int64_t abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

      int tmp32 = 0;

      if (abs_coeff * wt >=

          (dequant_ptr[rc != 0] << (AOM_QM_BITS - (1 + log_scale)))) {

        abs_coeff += rounding[rc != 0];

        abs_coeff = clamp64(abs_coeff, INT16_MIN, INT16_MAX);

        tmp32 = (int)((abs_coeff * wt * quant_ptr[rc != 0]) >>

                      (16 - log_scale + AOM_QM_BITS));

        qcoeff_ptr[rc] = (tmp32 ^ coeff_sign) - coeff_sign;

        const tran_low_t abs_dqcoeff = (tmp32 * dequant) >> log_scale;

        dqcoeff_ptr[rc] = (abs_dqcoeff ^ coeff_sign) - coeff_sign;

      }

      if (tmp32) eob = i;

    }

    *eob_ptr = eob + 1;

  }

}

#if CONFIG_AV1_HIGHBITDEPTH

static void highbd_quantize_fp_helper_c(

    const tran_low_t *coeff_ptr, intptr_t count, const int16_t *zbin_ptr,

    const int16_t *round_ptr, const int16_t *quant_ptr,

    const int16_t *quant_shift_ptr, tran_low_t *qcoeff_ptr,

    tran_low_t *dqcoeff_ptr, const int16_t *dequant_ptr, uint16_t *eob_ptr,

    const int16_t *scan, const int16_t *iscan, const qm_val_t *qm_ptr,

    const qm_val_t *iqm_ptr, int log_scale) {

  int i;

  int eob = -1;

  const int shift = 16 - log_scale;

  // TODO(jingning) Decide the need of these arguments after the

  // quantization process is completed.

  (void)zbin_ptr;

  (void)quant_shift_ptr;

  (void)iscan;

  if (qm_ptr || iqm_ptr) {

    // Quantization pass: All coefficients with index >= zero_flag are

    // skippable. Note: zero_flag can be zero.

    for (i = 0; i < count; i++) {

      const int rc = scan[i];

      const int coeff = coeff_ptr[rc];

      const qm_val_t wt = qm_ptr != NULL ? qm_ptr[rc] : (1 << AOM_QM_BITS);

      const qm_val_t iwt = iqm_ptr != NULL ? iqm_ptr[rc] : (1 << AOM_QM_BITS);

      const int dequant =

          (dequant_ptr[rc != 0] * iwt + (1 << (AOM_QM_BITS - 1))) >>

          AOM_QM_BITS;

      const int coeff_sign = AOMSIGN(coeff);

      const int64_t abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

      int abs_qcoeff = 0;

      if (abs_coeff * wt >=

          (dequant_ptr[rc != 0] << (AOM_QM_BITS - (1 + log_scale)))) {

        const int64_t tmp =

            abs_coeff + ROUND_POWER_OF_TWO(round_ptr[rc != 0], log_scale);

        abs_qcoeff =

            (int)((tmp * quant_ptr[rc != 0] * wt) >> (shift + AOM_QM_BITS));

        qcoeff_ptr[rc] = (tran_low_t)((abs_qcoeff ^ coeff_sign) - coeff_sign);

        const tran_low_t abs_dqcoeff = (abs_qcoeff * dequant) >> log_scale;

        dqcoeff_ptr[rc] = (tran_low_t)((abs_dqcoeff ^ coeff_sign) - coeff_sign);

        if (abs_qcoeff) eob = i;

      } else {

        qcoeff_ptr[rc] = 0;

        dqcoeff_ptr[rc] = 0;

      }

    }

  } else {

    const int log_scaled_round_arr[2] = {

      ROUND_POWER_OF_TWO(round_ptr[0], log_scale),

      ROUND_POWER_OF_TWO(round_ptr[1], log_scale),

    };

    for (i = 0; i < count; i++) {

      const int rc = scan[i];

      const int coeff = coeff_ptr[rc];

      const int rc01 = (rc != 0);

      const int coeff_sign = AOMSIGN(coeff);

      const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

      const int log_scaled_round = log_scaled_round_arr[rc01];

      if ((abs_coeff << (1 + log_scale)) >= dequant_ptr[rc01]) {

        const int quant = quant_ptr[rc01];

        const int dequant = dequant_ptr[rc01];

        const int64_t tmp = (int64_t)abs_coeff + log_scaled_round;

        const int abs_qcoeff = (int)((tmp * quant) >> shift);

        qcoeff_ptr[rc] = (tran_low_t)((abs_qcoeff ^ coeff_sign) - coeff_sign);

        const tran_low_t abs_dqcoeff = (abs_qcoeff * dequant) >> log_scale;

        if (abs_qcoeff) eob = i;

        dqcoeff_ptr[rc] = (tran_low_t)((abs_dqcoeff ^ coeff_sign) - coeff_sign);

      } else {

        qcoeff_ptr[rc] = 0;

        dqcoeff_ptr[rc] = 0;

      }

    }

  }

  *eob_ptr = eob + 1;

}

#endif  // CONFIG_AV1_HIGHBITDEPTH

void av1_quantize_fp_c(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                       const int16_t *zbin_ptr, const int16_t *round_ptr,

                       const int16_t *quant_ptr, const int16_t *quant_shift_ptr,

                       tran_low_t *qcoeff_ptr, tran_low_t *dqcoeff_ptr,

                       const int16_t *dequant_ptr, uint16_t *eob_ptr,

                       const int16_t *scan, const int16_t *iscan) {

  quantize_fp_helper_c(coeff_ptr, n_coeffs, zbin_ptr, round_ptr, quant_ptr,

                       quant_shift_ptr, qcoeff_ptr, dqcoeff_ptr, dequant_ptr,

                       eob_ptr, scan, iscan, NULL, NULL, 0);

}

void av1_quantize_lp_c(const int16_t *coeff_ptr, intptr_t n_coeffs,

                       const int16_t *round_ptr, const int16_t *quant_ptr,

                       int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,

                       const int16_t *dequant_ptr, uint16_t *eob_ptr,

                       const int16_t *scan, const int16_t *iscan) {

  (void)iscan;

  int eob = -1;

  memset(qcoeff_ptr, 0, n_coeffs * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, n_coeffs * sizeof(*dqcoeff_ptr));

  // Quantization pass: All coefficients with index >= zero_flag are

  // skippable. Note: zero_flag can be zero.

  for (int i = 0; i < n_coeffs; i++) {

    const int rc = scan[i];

    const int coeff = coeff_ptr[rc];

    const int coeff_sign = AOMSIGN(coeff);

    const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

    int tmp = clamp(abs_coeff + round_ptr[rc != 0], INT16_MIN, INT16_MAX);

    tmp = (tmp * quant_ptr[rc != 0]) >> 16;

    qcoeff_ptr[rc] = (tmp ^ coeff_sign) - coeff_sign;

    dqcoeff_ptr[rc] = qcoeff_ptr[rc] * dequant_ptr[rc != 0];

    if (tmp) eob = i;

  }

  *eob_ptr = eob + 1;

}

void av1_quantize_fp_32x32_c(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                             const int16_t *zbin_ptr, const int16_t *round_ptr,

                             const int16_t *quant_ptr,

                             const int16_t *quant_shift_ptr,

                             tran_low_t *qcoeff_ptr, tran_low_t *dqcoeff_ptr,

                             const int16_t *dequant_ptr, uint16_t *eob_ptr,

                             const int16_t *scan, const int16_t *iscan) {

  quantize_fp_helper_c(coeff_ptr, n_coeffs, zbin_ptr, round_ptr, quant_ptr,

                       quant_shift_ptr, qcoeff_ptr, dqcoeff_ptr, dequant_ptr,

                       eob_ptr, scan, iscan, NULL, NULL, 1);

}

void av1_quantize_fp_64x64_c(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                             const int16_t *zbin_ptr, const int16_t *round_ptr,

                             const int16_t *quant_ptr,

                             const int16_t *quant_shift_ptr,

                             tran_low_t *qcoeff_ptr, tran_low_t *dqcoeff_ptr,

                             const int16_t *dequant_ptr, uint16_t *eob_ptr,

                             const int16_t *scan, const int16_t *iscan) {

  quantize_fp_helper_c(coeff_ptr, n_coeffs, zbin_ptr, round_ptr, quant_ptr,

                       quant_shift_ptr, qcoeff_ptr, dqcoeff_ptr, dequant_ptr,

                       eob_ptr, scan, iscan, NULL, NULL, 2);

}

void av1_quantize_fp_facade(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                            const MACROBLOCK_PLANE *p, tran_low_t *qcoeff_ptr,

                            tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                            const SCAN_ORDER *sc, const QUANT_PARAM *qparam) {

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

  if (qm_ptr != NULL && iqm_ptr != NULL) {

    quantize_fp_helper_c(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX,

                         p->quant_fp_QTX, p->quant_shift_QTX, qcoeff_ptr,

                         dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                         sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

  } else {

    switch (qparam->log_scale) {

      case 0:

        av1_quantize_fp(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX,

                        p->quant_fp_QTX, p->quant_shift_QTX, qcoeff_ptr,

                        dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                        sc->iscan);

        break;

      case 1:

        av1_quantize_fp_32x32(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX,

                              p->quant_fp_QTX, p->quant_shift_QTX, qcoeff_ptr,

                              dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                              sc->iscan);

        break;

      case 2:

        av1_quantize_fp_64x64(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX,

                              p->quant_fp_QTX, p->quant_shift_QTX, qcoeff_ptr,

                              dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                              sc->iscan);

        break;

      default: assert(0);

    }

  }

}

void av1_quantize_b_facade(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                           const MACROBLOCK_PLANE *p, tran_low_t *qcoeff_ptr,

                           tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                           const SCAN_ORDER *sc, const QUANT_PARAM *qparam) {

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

#if !CONFIG_REALTIME_ONLY

  if (qparam->use_quant_b_adapt) {

    // TODO(sarahparker) These quantize_b optimizations need SIMD

    // implementations

    if (qm_ptr != NULL && iqm_ptr != NULL) {

      aom_quantize_b_adaptive_helper_c(

          coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

          p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX, eob_ptr,

          sc->scan, sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

    } else {

      switch (qparam->log_scale) {

        case 0:

          aom_quantize_b_adaptive(coeff_ptr, n_coeffs, p->zbin_QTX,

                                  p->round_QTX, p->quant_QTX,

                                  p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr,

                                  p->dequant_QTX, eob_ptr, sc->scan, sc->iscan);

          break;

        case 1:

          aom_quantize_b_32x32_adaptive(

              coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

              p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

              eob_ptr, sc->scan, sc->iscan);

          break;

        case 2:

          aom_quantize_b_64x64_adaptive(

              coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

              p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

              eob_ptr, sc->scan, sc->iscan);

          break;

        default: assert(0);

      }

    }

    return;

  }

#endif  // !CONFIG_REALTIME_ONLY

  if (qm_ptr != NULL && iqm_ptr != NULL) {

    aom_quantize_b_helper_c(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX,

                            p->quant_QTX, p->quant_shift_QTX, qcoeff_ptr,

                            dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                            sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

  } else {

    switch (qparam->log_scale) {

      case 0:

        aom_quantize_b(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX,

                       p->quant_QTX, p->quant_shift_QTX, qcoeff_ptr,

                       dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                       sc->iscan);

        break;

      case 1:

        aom_quantize_b_32x32(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX,

                             p->quant_QTX, p->quant_shift_QTX, qcoeff_ptr,

                             dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                             sc->iscan);

        break;

      case 2:

        aom_quantize_b_64x64(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX,

                             p->quant_QTX, p->quant_shift_QTX, qcoeff_ptr,

                             dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                             sc->iscan);

        break;

      default: assert(0);

    }

  }

}

static void quantize_dc(const tran_low_t *coeff_ptr, int n_coeffs,

                        int skip_block, const int16_t *round_ptr,

                        const int16_t quant, tran_low_t *qcoeff_ptr,

                        tran_low_t *dqcoeff_ptr, const int16_t dequant_ptr,

                        uint16_t *eob_ptr, const qm_val_t *qm_ptr,

                        const qm_val_t *iqm_ptr, const int log_scale) {

  const int rc = 0;

  const int coeff = coeff_ptr[rc];

  const int coeff_sign = AOMSIGN(coeff);

  const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

  int64_t tmp;

  int eob = -1;

  int32_t tmp32;

  int dequant;

  memset(qcoeff_ptr, 0, n_coeffs * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, n_coeffs * sizeof(*dqcoeff_ptr));

  if (!skip_block) {

    const int wt = qm_ptr != NULL ? qm_ptr[rc] : (1 << AOM_QM_BITS);

    const int iwt = iqm_ptr != NULL ? iqm_ptr[rc] : (1 << AOM_QM_BITS);

    tmp = clamp(abs_coeff + ROUND_POWER_OF_TWO(round_ptr[rc != 0], log_scale),

                INT16_MIN, INT16_MAX);

    tmp32 = (int32_t)((tmp * wt * quant) >> (16 - log_scale + AOM_QM_BITS));

    qcoeff_ptr[rc] = (tmp32 ^ coeff_sign) - coeff_sign;

    dequant = (dequant_ptr * iwt + (1 << (AOM_QM_BITS - 1))) >> AOM_QM_BITS;

    const tran_low_t abs_dqcoeff = (tmp32 * dequant) >> log_scale;

    dqcoeff_ptr[rc] = (tran_low_t)((abs_dqcoeff ^ coeff_sign) - coeff_sign);

    if (tmp32) eob = 0;

  }

  *eob_ptr = eob + 1;

}

void av1_quantize_dc_facade(const tran_low_t *coeff_ptr, intptr_t n_coeffs,

                            const MACROBLOCK_PLANE *p, tran_low_t *qcoeff_ptr,

                            tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                            const SCAN_ORDER *sc, const QUANT_PARAM *qparam) {

  // obsolete skip_block

  const int skip_block = 0;

  (void)sc;

  assert(qparam->log_scale >= 0 && qparam->log_scale < (3));

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

  quantize_dc(coeff_ptr, (int)n_coeffs, skip_block, p->round_QTX,

              p->quant_fp_QTX[0], qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX[0],

              eob_ptr, qm_ptr, iqm_ptr, qparam->log_scale);

}

#if CONFIG_AV1_HIGHBITDEPTH

void av1_highbd_quantize_fp_facade(const tran_low_t *coeff_ptr,

                                   intptr_t n_coeffs, const MACROBLOCK_PLANE *p,

                                   tran_low_t *qcoeff_ptr,

                                   tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                                   const SCAN_ORDER *sc,

                                   const QUANT_PARAM *qparam) {

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

  if (qm_ptr != NULL && iqm_ptr != NULL) {

    highbd_quantize_fp_helper_c(

        coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX, p->quant_fp_QTX,

        p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX, eob_ptr,

        sc->scan, sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

  } else {

    av1_highbd_quantize_fp(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_fp_QTX,

                           p->quant_fp_QTX, p->quant_shift_QTX, qcoeff_ptr,

                           dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                           sc->iscan, qparam->log_scale);

  }

}

void av1_highbd_quantize_b_facade(const tran_low_t *coeff_ptr,

                                  intptr_t n_coeffs, const MACROBLOCK_PLANE *p,

                                  tran_low_t *qcoeff_ptr,

                                  tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                                  const SCAN_ORDER *sc,

                                  const QUANT_PARAM *qparam) {

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

#if !CONFIG_REALTIME_ONLY

  if (qparam->use_quant_b_adapt) {

    if (qm_ptr != NULL && iqm_ptr != NULL) {

      aom_highbd_quantize_b_adaptive_helper_c(

          coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

          p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX, eob_ptr,

          sc->scan, sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

    } else {

      switch (qparam->log_scale) {

        case 0:

          aom_highbd_quantize_b_adaptive(

              coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

              p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

              eob_ptr, sc->scan, sc->iscan);

          break;

        case 1:

          aom_highbd_quantize_b_32x32_adaptive(

              coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

              p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

              eob_ptr, sc->scan, sc->iscan);

          break;

        case 2:

          aom_highbd_quantize_b_64x64_adaptive(

              coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

              p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

              eob_ptr, sc->scan, sc->iscan);

          break;

        default: assert(0);

      }

    }

    return;

  }

#endif  // !CONFIG_REALTIME_ONLY

  if (qm_ptr != NULL && iqm_ptr != NULL) {

    aom_highbd_quantize_b_helper_c(

        coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

        p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX, eob_ptr,

        sc->scan, sc->iscan, qm_ptr, iqm_ptr, qparam->log_scale);

  } else {

    switch (qparam->log_scale) {

      case 0:

        aom_highbd_quantize_b(coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX,

                              p->quant_QTX, p->quant_shift_QTX, qcoeff_ptr,

                              dqcoeff_ptr, p->dequant_QTX, eob_ptr, sc->scan,

                              sc->iscan);

        break;

      case 1:

        aom_highbd_quantize_b_32x32(

            coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

            p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

            eob_ptr, sc->scan, sc->iscan);

        break;

      case 2:

        aom_highbd_quantize_b_64x64(

            coeff_ptr, n_coeffs, p->zbin_QTX, p->round_QTX, p->quant_QTX,

            p->quant_shift_QTX, qcoeff_ptr, dqcoeff_ptr, p->dequant_QTX,

            eob_ptr, sc->scan, sc->iscan);

        break;

      default: assert(0);

    }

  }

}

static inline void highbd_quantize_dc(

    const tran_low_t *coeff_ptr, int n_coeffs, int skip_block,

    const int16_t *round_ptr, const int16_t quant, tran_low_t *qcoeff_ptr,

    tran_low_t *dqcoeff_ptr, const int16_t dequant_ptr, uint16_t *eob_ptr,

    const qm_val_t *qm_ptr, const qm_val_t *iqm_ptr, const int log_scale) {

  int eob = -1;

  memset(qcoeff_ptr, 0, n_coeffs * sizeof(*qcoeff_ptr));

  memset(dqcoeff_ptr, 0, n_coeffs * sizeof(*dqcoeff_ptr));

  if (!skip_block) {

    const qm_val_t wt = qm_ptr != NULL ? qm_ptr[0] : (1 << AOM_QM_BITS);

    const qm_val_t iwt = iqm_ptr != NULL ? iqm_ptr[0] : (1 << AOM_QM_BITS);

    const int coeff = coeff_ptr[0];

    const int coeff_sign = AOMSIGN(coeff);

    const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;

    const int64_t tmp = abs_coeff + ROUND_POWER_OF_TWO(round_ptr[0], log_scale);

    const int64_t tmpw = tmp * wt;

    const int abs_qcoeff =

        (int)((tmpw * quant) >> (16 - log_scale + AOM_QM_BITS));

    qcoeff_ptr[0] = (tran_low_t)((abs_qcoeff ^ coeff_sign) - coeff_sign);

    const int dequant =

        (dequant_ptr * iwt + (1 << (AOM_QM_BITS - 1))) >> AOM_QM_BITS;

    const tran_low_t abs_dqcoeff = (abs_qcoeff * dequant) >> log_scale;

    dqcoeff_ptr[0] = (tran_low_t)((abs_dqcoeff ^ coeff_sign) - coeff_sign);

    if (abs_qcoeff) eob = 0;

  }

  *eob_ptr = eob + 1;

}

void av1_highbd_quantize_dc_facade(const tran_low_t *coeff_ptr,

                                   intptr_t n_coeffs, const MACROBLOCK_PLANE *p,

                                   tran_low_t *qcoeff_ptr,

                                   tran_low_t *dqcoeff_ptr, uint16_t *eob_ptr,

                                   const SCAN_ORDER *sc,

                                   const QUANT_PARAM *qparam) {

  // obsolete skip_block

  const int skip_block = 0;

  const qm_val_t *qm_ptr = qparam->qmatrix;

  const qm_val_t *iqm_ptr = qparam->iqmatrix;

  (void)sc;

  highbd_quantize_dc(coeff_ptr, (int)n_coeffs, skip_block, p->round_QTX,

                     p->quant_fp_QTX[0], qcoeff_ptr, dqcoeff_ptr,

                     p->dequant_QTX[0], eob_ptr, qm_ptr, iqm_ptr,

                     qparam->log_scale);

}

void av1_highbd_quantize_fp_c(const tran_low_t *coeff_ptr, intptr_t count,

                              const int16_t *zbin_ptr, const int16_t *round_ptr,

                              const int16_t *quant_ptr,

                              const int16_t *quant_shift_ptr,

                              tran_low_t *qcoeff_ptr, tran_low_t *dqcoeff_ptr,

                              const int16_t *dequant_ptr, uint16_t *eob_ptr,

                              const int16_t *scan, const int16_t *iscan,

                              int log_scale) {

  highbd_quantize_fp_helper_c(coeff_ptr, count, zbin_ptr, round_ptr, quant_ptr,

                              quant_shift_ptr, qcoeff_ptr, dqcoeff_ptr,

                              dequant_ptr, eob_ptr, scan, iscan, NULL, NULL,

                              log_scale);

}

#endif  // CONFIG_AV1_HIGHBITDEPTH

static void invert_quant(int16_t *quant, int16_t *shift, int d) {

  uint32_t t;

  int l, m;

  t = d;

  l = get_msb(t);

  m = 1 + (1 << (16 + l)) / d;

  *quant = (int16_t)(m - (1 << 16));

  *shift = 1 << (16 - l);

}

static int get_qzbin_factor(int q, aom_bit_depth_t bit_depth) {

  const int quant = av1_dc_quant_QTX(q, 0, bit_depth);

  switch (bit_depth) {

    case AOM_BITS_8: return q == 0 ? 64 : (quant < 148 ? 84 : 80);

    case AOM_BITS_10: return q == 0 ? 64 : (quant < 592 ? 84 : 80);

    case AOM_BITS_12: return q == 0 ? 64 : (quant < 2368 ? 84 : 80);

    default:

      assert(0 && "bit_depth should be AOM_BITS_8, AOM_BITS_10 or AOM_BITS_12");

      return -1;

  }

}

void av1_build_quantizer(aom_bit_depth_t bit_depth, int y_dc_delta_q,

                         int u_dc_delta_q, int u_ac_delta_q, int v_dc_delta_q,

                         int v_ac_delta_q, QUANTS *const quants,

                         Dequants *const deq, int sharpness) {

  int i, q, quant_QTX;

  const int sharpness_adjustment = 16 * (7 - sharpness) / 7;

  for (q = 0; q < QINDEX_RANGE; q++) {

    const int qzbin_factor = get_qzbin_factor(q, bit_depth);

    int qrounding_factor = q == 0 ? 64 : 48;

    for (i = 0; i < 2; ++i) {

      int qrounding_factor_fp = 64;

      if (sharpness != 0 && q != 0) {

        qrounding_factor = 64 - sharpness_adjustment;

        qrounding_factor_fp = 64 - sharpness_adjustment;

      }

      // y quantizer with TX scale

      quant_QTX = i == 0 ? av1_dc_quant_QTX(q, y_dc_delta_q, bit_depth)

                         : av1_ac_quant_QTX(q, 0, bit_depth);

      invert_quant(&quants->y_quant[q][i], &quants->y_quant_shift[q][i],

                   quant_QTX);

      quants->y_quant_fp[q][i] = (1 << 16) / quant_QTX;

      quants->y_round_fp[q][i] = (qrounding_factor_fp * quant_QTX) >> 7;

      quants->y_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant_QTX, 7);

      quants->y_round[q][i] = (qrounding_factor * quant_QTX) >> 7;

      deq->y_dequant_QTX[q][i] = quant_QTX;

      // u quantizer with TX scale

      quant_QTX = i == 0 ? av1_dc_quant_QTX(q, u_dc_delta_q, bit_depth)

                         : av1_ac_quant_QTX(q, u_ac_delta_q, bit_depth);

      invert_quant(&quants->u_quant[q][i], &quants->u_quant_shift[q][i],

                   quant_QTX);

      quants->u_quant_fp[q][i] = (1 << 16) / quant_QTX;

      quants->u_round_fp[q][i] = (qrounding_factor_fp * quant_QTX) >> 7;

      quants->u_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant_QTX, 7);

      quants->u_round[q][i] = (qrounding_factor * quant_QTX) >> 7;

      deq->u_dequant_QTX[q][i] = quant_QTX;

      // v quantizer with TX scale

      quant_QTX = i == 0 ? av1_dc_quant_QTX(q, v_dc_delta_q, bit_depth)

                         : av1_ac_quant_QTX(q, v_ac_delta_q, bit_depth);

      invert_quant(&quants->v_quant[q][i], &quants->v_quant_shift[q][i],

                   quant_QTX);

      quants->v_quant_fp[q][i] = (1 << 16) / quant_QTX;

      quants->v_round_fp[q][i] = (qrounding_factor_fp * quant_QTX) >> 7;

      quants->v_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant_QTX, 7);

      quants->v_round[q][i] = (qrounding_factor * quant_QTX) >> 7;

      deq->v_dequant_QTX[q][i] = quant_QTX;

    }

    for (i = 2; i < 8; i++) {  // 8: SIMD width

      quants->y_quant[q][i] = quants->y_quant[q][1];

      quants->y_quant_fp[q][i] = quants->y_quant_fp[q][1];

      quants->y_round_fp[q][i] = quants->y_round_fp[q][1];

      quants->y_quant_shift[q][i] = quants->y_quant_shift[q][1];

      quants->y_zbin[q][i] = quants->y_zbin[q][1];

      quants->y_round[q][i] = quants->y_round[q][1];

      deq->y_dequant_QTX[q][i] = deq->y_dequant_QTX[q][1];

      quants->u_quant[q][i] = quants->u_quant[q][1];

      quants->u_quant_fp[q][i] = quants->u_quant_fp[q][1];

      quants->u_round_fp[q][i] = quants->u_round_fp[q][1];

      quants->u_quant_shift[q][i] = quants->u_quant_shift[q][1];

      quants->u_zbin[q][i] = quants->u_zbin[q][1];

      quants->u_round[q][i] = quants->u_round[q][1];

      deq->u_dequant_QTX[q][i] = deq->u_dequant_QTX[q][1];

      quants->v_quant[q][i] = quants->v_quant[q][1];

      quants->v_quant_fp[q][i] = quants->v_quant_fp[q][1];

      quants->v_round_fp[q][i] = quants->v_round_fp[q][1];

      quants->v_quant_shift[q][i] = quants->v_quant_shift[q][1];

      quants->v_zbin[q][i] = quants->v_zbin[q][1];

      quants->v_round[q][i] = quants->v_round[q][1];

      deq->v_dequant_QTX[q][i] = deq->v_dequant_QTX[q][1];

    }

  }

}

static inline bool deltaq_params_have_changed(

    const DeltaQuantParams *prev_deltaq_params,

    const CommonQuantParams *quant_params) {

  return (prev_deltaq_params->y_dc_delta_q != quant_params->y_dc_delta_q ||

          prev_deltaq_params->u_dc_delta_q != quant_params->u_dc_delta_q ||

          prev_deltaq_params->v_dc_delta_q != quant_params->v_dc_delta_q ||

          prev_deltaq_params->u_ac_delta_q != quant_params->u_ac_delta_q ||

          prev_deltaq_params->v_ac_delta_q != quant_params->v_ac_delta_q ||

          prev_deltaq_params->sharpness != quant_params->sharpness);

}

void av1_init_quantizer(EncQuantDequantParams *const enc_quant_dequant_params,

                        CommonQuantParams *quant_params,

                        aom_bit_depth_t bit_depth, int sharpness) {

  DeltaQuantParams *const prev_deltaq_params =

      &enc_quant_dequant_params->prev_deltaq_params;

  quant_params->sharpness = sharpness;

  // Re-initialize the quantizer only if any of the dc/ac deltaq parameters

  // change.

  if (!deltaq_params_have_changed(prev_deltaq_params, quant_params)) return;

  QUANTS *const quants = &enc_quant_dequant_params->quants;

  Dequants *const dequants = &enc_quant_dequant_params->dequants;

  av1_build_quantizer(bit_depth, quant_params->y_dc_delta_q,

                      quant_params->u_dc_delta_q, quant_params->u_ac_delta_q,

                      quant_params->v_dc_delta_q, quant_params->v_ac_delta_q,

                      quants, dequants, sharpness);

  // Record the state of deltaq parameters.

  prev_deltaq_params->y_dc_delta_q = quant_params->y_dc_delta_q;

  prev_deltaq_params->u_dc_delta_q = quant_params->u_dc_delta_q;

  prev_deltaq_params->v_dc_delta_q = quant_params->v_dc_delta_q;

  prev_deltaq_params->u_ac_delta_q = quant_params->u_ac_delta_q;

  prev_deltaq_params->v_ac_delta_q = quant_params->v_ac_delta_q;

  prev_deltaq_params->sharpness = sharpness;

}

/*!\brief Update quantize parameters in MACROBLOCK

 *

 * \param[in]  enc_quant_dequant_params This parameter cached the quantize and

 *                                      dequantize parameters for all q

 *                                      indices.

 * \param[in]  qindex                   Quantize index used for the current

 *                                      superblock.

 * \param[out] x                        A superblock data structure for

 *                                      encoder.

 */

static void set_q_index(const EncQuantDequantParams *enc_quant_dequant_params,

                        int qindex, MACROBLOCK *x) {

  const QUANTS *const quants = &enc_quant_dequant_params->quants;

  const Dequants *const dequants = &enc_quant_dequant_params->dequants;

  x->qindex = qindex;

  x->seg_skip_block =

      0;  // TODO(angiebird): Find a proper place to init this variable.

  // Y

  x->plane[0].quant_QTX = quants->y_quant[qindex];

  x->plane[0].quant_fp_QTX = quants->y_quant_fp[qindex];

  x->plane[0].round_fp_QTX = quants->y_round_fp[qindex];

  x->plane[0].quant_shift_QTX = quants->y_quant_shift[qindex];

  x->plane[0].zbin_QTX = quants->y_zbin[qindex];

  x->plane[0].round_QTX = quants->y_round[qindex];

  x->plane[0].dequant_QTX = dequants->y_dequant_QTX[qindex];

  // U

  x->plane[1].quant_QTX = quants->u_quant[qindex];

  x->plane[1].quant_fp_QTX = quants->u_quant_fp[qindex];

  x->plane[1].round_fp_QTX = quants->u_round_fp[qindex];

  x->plane[1].quant_shift_QTX = quants->u_quant_shift[qindex];

  x->plane[1].zbin_QTX = quants->u_zbin[qindex];

  x->plane[1].round_QTX = quants->u_round[qindex];

  x->plane[1].dequant_QTX = dequants->u_dequant_QTX[qindex];

  // V

  x->plane[2].quant_QTX = quants->v_quant[qindex];

  x->plane[2].quant_fp_QTX = quants->v_quant_fp[qindex];

  x->plane[2].round_fp_QTX = quants->v_round_fp[qindex];

  x->plane[2].quant_shift_QTX = quants->v_quant_shift[qindex];

  x->plane[2].zbin_QTX = quants->v_zbin[qindex];

  x->plane[2].round_QTX = quants->v_round[qindex];

  x->plane[2].dequant_QTX = dequants->v_dequant_QTX[qindex];

}

/*!\brief Update quantize matrix in MACROBLOCKD based on segment id

 *

 * \param[in]  quant_params  Quantize parameters used by encoder and decoder

 * \param[in]  segment_id    Segment id.

 * \param[out] xd            A superblock data structure used by encoder and

 * decoder.

 */

static void set_qmatrix(const CommonQuantParams *quant_params, int segment_id,

                        MACROBLOCKD *xd) {

  const int use_qmatrix = av1_use_qmatrix(quant_params, xd, segment_id);

  const int qmlevel_y =

      use_qmatrix ? quant_params->qmatrix_level_y : NUM_QM_LEVELS - 1;

  const int qmlevel_u =

      use_qmatrix ? quant_params->qmatrix_level_u : NUM_QM_LEVELS - 1;

  const int qmlevel_v =

      use_qmatrix ? quant_params->qmatrix_level_v : NUM_QM_LEVELS - 1;

  const int qmlevel_ls[MAX_MB_PLANE] = { qmlevel_y, qmlevel_u, qmlevel_v };

  for (int i = 0; i < MAX_MB_PLANE; ++i) {

    const int qmlevel = qmlevel_ls[i];

    memcpy(&xd->plane[i].seg_qmatrix[segment_id],

           quant_params->gqmatrix[qmlevel][i],

           sizeof(quant_params->gqmatrix[qmlevel][i]));

    memcpy(&xd->plane[i].seg_iqmatrix[segment_id],

           quant_params->giqmatrix[qmlevel][i],

           sizeof(quant_params->giqmatrix[qmlevel][i]));

  }

}

void av1_init_plane_quantizers(const AV1_COMP *cpi, MACROBLOCK *x,

                               int segment_id, const int do_update) {

  const AV1_COMMON *const cm = &cpi->common;

  const CommonQuantParams *const quant_params = &cm->quant_params;

  const GF_GROUP *const gf_group = &cpi->ppi->gf_group;

  const int boost_index = AOMMIN(15, (cpi->ppi->p_rc.gfu_boost / 100));

  const int layer_depth = AOMMIN(gf_group->layer_depth[cpi->gf_frame_index], 6);

  const FRAME_TYPE frame_type = cm->current_frame.frame_type;

  int qindex_rd;

  const int current_qindex =

      clamp(cm->delta_q_info.delta_q_present_flag

                ? quant_params->base_qindex + x->delta_qindex

                : quant_params->base_qindex,

            0, QINDEX_RANGE - 1);

  const int qindex = av1_get_qindex(&cm->seg, segment_id, current_qindex);

  if (cpi->oxcf.sb_qp_sweep) {

    const int current_rd_qindex =

        clamp(cm->delta_q_info.delta_q_present_flag

                  ? quant_params->base_qindex + x->rdmult_delta_qindex

                  : quant_params->base_qindex,

              0, QINDEX_RANGE - 1);

    qindex_rd = av1_get_qindex(&cm->seg, segment_id, current_rd_qindex);

  } else {

    qindex_rd = qindex;

  }

  const int qindex_rdmult = qindex_rd + quant_params->y_dc_delta_q;

  const int rdmult = av1_compute_rd_mult(

      qindex_rdmult, cm->seq_params->bit_depth,

      cpi->ppi->gf_group.update_type[cpi->gf_frame_index], layer_depth,

      boost_index, frame_type, cpi->oxcf.q_cfg.use_fixed_qp_offsets,

      is_stat_consumption_stage(cpi), cpi->oxcf.tune_cfg.tuning);

  const int qindex_change = x->qindex != qindex;

  if (qindex_change || do_update) {

    set_q_index(&cpi->enc_quant_dequant_params, qindex, x);

  }

  MACROBLOCKD *const xd = &x->e_mbd;

  if ((segment_id != x->prev_segment_id) ||

      av1_use_qmatrix(quant_params, xd, segment_id)) {

    set_qmatrix(quant_params, segment_id, xd);

  }

  x->seg_skip_block = segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP);

  av1_set_error_per_bit(&x->errorperbit, rdmult);

  av1_set_sad_per_bit(cpi, &x->sadperbit, qindex_rd);

  x->prev_segment_id = segment_id;

}

void av1_frame_init_quantizer(AV1_COMP *cpi) {

  MACROBLOCK *const x = &cpi->td.mb;

  MACROBLOCKD *const xd = &x->e_mbd;

  x->prev_segment_id = -1;

  av1_init_plane_quantizers(cpi, x, xd->mi[0]->segment_id, 1);

}

static int adjust_hdr_cb_deltaq(int base_qindex) {

  double baseQp = base_qindex / QP_SCALE_FACTOR;

  const double chromaQp = CHROMA_QP_SCALE * baseQp + CHROMA_QP_OFFSET;

  const double dcbQP = CHROMA_CB_QP_SCALE * chromaQp * QP_SCALE_FACTOR;

  int dqpCb = (int)(dcbQP + (dcbQP < 0 ? -0.5 : 0.5));

  dqpCb = AOMMIN(0, dqpCb);

  dqpCb = (int)CLIP(dqpCb, -12 * QP_SCALE_FACTOR, 12 * QP_SCALE_FACTOR);

  return dqpCb;

}

static int adjust_hdr_cr_deltaq(int base_qindex) {

  double baseQp = base_qindex / QP_SCALE_FACTOR;

  const double chromaQp = CHROMA_QP_SCALE * baseQp + CHROMA_QP_OFFSET;

  const double dcrQP = CHROMA_CR_QP_SCALE * chromaQp * QP_SCALE_FACTOR;

  int dqpCr = (int)(dcrQP + (dcrQP < 0 ? -0.5 : 0.5));

  dqpCr = AOMMIN(0, dqpCr);

  dqpCr = (int)CLIP(dqpCr, -12 * QP_SCALE_FACTOR, 12 * QP_SCALE_FACTOR);

  return dqpCr;

}

void av1_set_quantizer(AV1_COMMON *const cm, int min_qmlevel, int max_qmlevel,

                       int q, int enable_chroma_deltaq, int enable_hdr_deltaq,

                       bool is_allintra, aom_tune_metric tuning) {

  // quantizer has to be reinitialized with av1_init_quantizer() if any

  // delta_q changes.

  CommonQuantParams *quant_params = &cm->quant_params;

  quant_params->base_qindex = AOMMAX(cm->delta_q_info.delta_q_present_flag, q);

  quant_params->y_dc_delta_q = 0;

  // Disable deltaq in lossless mode.

  if (enable_chroma_deltaq && q) {

    if (is_allintra &&

        (tuning == AOM_TUNE_IQ || tuning == AOM_TUNE_SSIMULACRA2)) {

      int chroma_dc_delta_q = 0;

      int chroma_ac_delta_q = 0;

      if (cm->seq_params->subsampling_x == 1 &&

          cm->seq_params->subsampling_y == 1) {

        // 4:2:0 subsampling: Constant chroma delta_q decrease (i.e. improved

        // chroma quality relative to luma) with gradual ramp-down for very low

        // qindexes.

        // Lowering chroma delta_q by 16 was found to improve SSIMULACRA 2

        // BD-Rate by 1.5-2% on Daala's subset1, as well as reducing chroma

        // artifacts (smudging, discoloration) during subjective quality

        // evaluations.

        // The ramp-down of chroma increase was determined by generating the

        // convex hull of SSIMULACRA 2 scores (for all boosts from 0-16), and

        // finding a linear equation that fits the convex hull.

        chroma_dc_delta_q = -clamp((quant_params->base_qindex / 2) - 14, 0, 16);

        chroma_ac_delta_q = chroma_dc_delta_q;

      } else if (cm->seq_params->subsampling_x == 1 &&

                 cm->seq_params->subsampling_y == 0) {

        // 4:2:2 subsampling: Constant chroma AC delta_q increase (i.e. improved

        // luma quality relative to chroma) with gradual ramp-down for very low

        // qindexes.

        // SSIMULACRA 2 appears to have some issues correctly scoring 4:2:2

        // material. Solely optimizing for maximum scores suggests a chroma AC

        // delta_q of 12 is the most efficient. However, visual inspection on

        // difficult-to-encode material resulted in chroma quality degrading too

        // much relative to luma, and chroma channels ending up being too small

        // compared to equivalent 4:4:4 or 4:2:0 encodes.

        // A chroma AC delta_q of 6 was selected because encoded chroma channels

        // have a much closer size to 4:4:4 and 4:2:0 encodes, and have more

        // favorable visual quality characteristics.

        // The ramp-down of chroma decrease was put into place to match 4:2:0

        // and 4:4:4 behavior. There were no special considerations on

        // SSIMULACRA 2 scores.

        chroma_dc_delta_q = 0;

        chroma_ac_delta_q = clamp((quant_params->base_qindex / 2), 0, 6);

      } else if (cm->seq_params->subsampling_x == 0 &&

                 cm->seq_params->subsampling_y == 0) {

        // 4:4:4 subsampling: Constant chroma AC delta_q increase (i.e. improved

        // luma quality relative to chroma) with gradual ramp-down for very low

        // qindexes.

        // Raising chroma AC delta_q by 24 was found to improve SSIMULACRA 2

        // BD-Rate by 2.5-3% on Daala's subset1, as well as providing a more

        // balanced bit allocation between the (relatively-starved) luma and

        // chroma channels.

        // Raising chroma DC delta_q appears to be harmful, both for SSIMULACRA

        // 2 scores and subjective quality (harshens blocking artifacts).