xref: /aosp_15_r20/external/libvpx/vp9/encoder/vp9_rd.c (revision fb1b10ab9aebc7c7068eedab379b749d7e3900be)

/*
 *  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 <assert.h>
#include <math.h>
#include <stdio.h>

#include "./vp9_rtcd.h"

#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_mem/vpx_mem.h"
#include "vpx_ports/bitops.h"
#include "vpx_ports/mem.h"
#include "vpx_ports/system_state.h"

#include "vp9/common/vp9_common.h"
#include "vp9/common/vp9_entropy.h"
#include "vp9/common/vp9_entropymode.h"
#include "vp9/common/vp9_mvref_common.h"
#include "vp9/common/vp9_pred_common.h"
#include "vp9/common/vp9_quant_common.h"
#include "vp9/common/vp9_reconinter.h"
#include "vp9/common/vp9_reconintra.h"
#include "vp9/common/vp9_seg_common.h"

#include "vp9/encoder/vp9_cost.h"
#include "vp9/encoder/vp9_encodemb.h"
#include "vp9/encoder/vp9_encodemv.h"
#include "vp9/encoder/vp9_encoder.h"
#include "vp9/encoder/vp9_mcomp.h"
#include "vp9/encoder/vp9_quantize.h"
#include "vp9/encoder/vp9_ratectrl.h"
#include "vp9/encoder/vp9_rd.h"
#include "vp9/encoder/vp9_tokenize.h"

#define RD_THRESH_POW 1.25

// Factor to weigh the rate for switchable interp filters.
#define SWITCHABLE_INTERP_RATE_FACTOR 1

void vp9_rd_cost_reset(RD_COST *rd_cost) {
  rd_cost->rate = INT_MAX;
  rd_cost->dist = INT64_MAX;
  rd_cost->rdcost = INT64_MAX;
}

void vp9_rd_cost_init(RD_COST *rd_cost) {
  rd_cost->rate = 0;
  rd_cost->dist = 0;
  rd_cost->rdcost = 0;
}

int64_t vp9_calculate_rd_cost(int mult, int div, int rate, int64_t dist) {
  assert(mult >= 0);
  assert(div > 0);
  if (rate >= 0 && dist >= 0) {
    return RDCOST(mult, div, rate, dist);
  }
  if (rate >= 0 && dist < 0) {
    return RDCOST_NEG_D(mult, div, rate, -dist);
  }
  if (rate < 0 && dist >= 0) {
    return RDCOST_NEG_R(mult, div, -rate, dist);
  }
  return -RDCOST(mult, div, -rate, -dist);
}

void vp9_rd_cost_update(int mult, int div, RD_COST *rd_cost) {
  if (rd_cost->rate < INT_MAX && rd_cost->dist < INT64_MAX) {
    rd_cost->rdcost =
        vp9_calculate_rd_cost(mult, div, rd_cost->rate, rd_cost->dist);
  } else {
    vp9_rd_cost_reset(rd_cost);
  }
}

// The baseline rd thresholds for breaking out of the rd loop for
// certain modes are assumed to be based on 8x8 blocks.
// This table is used to correct for block size.
// The factors here are << 2 (2 = x0.5, 32 = x8 etc).
static const uint8_t rd_thresh_block_size_factor[BLOCK_SIZES] = {
  2, 3, 3, 4, 6, 6, 8, 12, 12, 16, 24, 24, 32
};

static void fill_mode_costs(VP9_COMP *cpi) {
  const FRAME_CONTEXT *const fc = cpi->common.fc;
  int i, j;

  for (i = 0; i < INTRA_MODES; ++i) {
    for (j = 0; j < INTRA_MODES; ++j) {
      vp9_cost_tokens(cpi->y_mode_costs[i][j], vp9_kf_y_mode_prob[i][j],
                      vp9_intra_mode_tree);
    }
  }

  vp9_cost_tokens(cpi->mbmode_cost, fc->y_mode_prob[1], vp9_intra_mode_tree);
  for (i = 0; i < INTRA_MODES; ++i) {
    vp9_cost_tokens(cpi->intra_uv_mode_cost[KEY_FRAME][i],
                    vp9_kf_uv_mode_prob[i], vp9_intra_mode_tree);
    vp9_cost_tokens(cpi->intra_uv_mode_cost[INTER_FRAME][i],
                    fc->uv_mode_prob[i], vp9_intra_mode_tree);
  }

  for (i = 0; i < SWITCHABLE_FILTER_CONTEXTS; ++i) {
    vp9_cost_tokens(cpi->switchable_interp_costs[i],
                    fc->switchable_interp_prob[i], vp9_switchable_interp_tree);
  }

  for (i = TX_8X8; i < TX_SIZES; ++i) {
    for (j = 0; j < TX_SIZE_CONTEXTS; ++j) {
      const vpx_prob *tx_probs = get_tx_probs(i, j, &fc->tx_probs);
      int k;
      for (k = 0; k <= i; ++k) {
        int cost = 0;
        int m;
        for (m = 0; m <= k - (k == i); ++m) {
          if (m == k)
            cost += vp9_cost_zero(tx_probs[m]);
          else
            cost += vp9_cost_one(tx_probs[m]);
        }
        cpi->tx_size_cost[i - 1][j][k] = cost;
      }
    }
  }
}

static void fill_token_costs(vp9_coeff_cost *c,
                             vp9_coeff_probs_model (*p)[PLANE_TYPES]) {
  int i, j, k, l;
  TX_SIZE t;
  for (t = TX_4X4; t <= TX_32X32; ++t)
    for (i = 0; i < PLANE_TYPES; ++i)
      for (j = 0; j < REF_TYPES; ++j)
        for (k = 0; k < COEF_BANDS; ++k)
          for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
            vpx_prob probs[ENTROPY_NODES];
            vp9_model_to_full_probs(p[t][i][j][k][l], probs);
            vp9_cost_tokens((int *)c[t][i][j][k][0][l], probs, vp9_coef_tree);
            vp9_cost_tokens_skip((int *)c[t][i][j][k][1][l], probs,
                                 vp9_coef_tree);
            assert(c[t][i][j][k][0][l][EOB_TOKEN] ==
                   c[t][i][j][k][1][l][EOB_TOKEN]);
          }
}

// Values are now correlated to quantizer.
static int sad_per_bit16lut_8[QINDEX_RANGE];
static int sad_per_bit4lut_8[QINDEX_RANGE];

#if CONFIG_VP9_HIGHBITDEPTH
static int sad_per_bit16lut_10[QINDEX_RANGE];
static int sad_per_bit4lut_10[QINDEX_RANGE];
static int sad_per_bit16lut_12[QINDEX_RANGE];
static int sad_per_bit4lut_12[QINDEX_RANGE];
#endif

static void init_me_luts_bd(int *bit16lut, int *bit4lut, int range,
                            vpx_bit_depth_t bit_depth) {
  int i;
  // Initialize the sad lut tables using a formulaic calculation for now.
  // This is to make it easier to resolve the impact of experimental changes
  // to the quantizer tables.
  for (i = 0; i < range; i++) {
    const double q = vp9_convert_qindex_to_q(i, bit_depth);
    bit16lut[i] = (int)(0.0418 * q + 2.4107);
    bit4lut[i] = (int)(0.063 * q + 2.742);
  }
}

void vp9_init_me_luts(void) {
  init_me_luts_bd(sad_per_bit16lut_8, sad_per_bit4lut_8, QINDEX_RANGE,
                  VPX_BITS_8);
#if CONFIG_VP9_HIGHBITDEPTH
  init_me_luts_bd(sad_per_bit16lut_10, sad_per_bit4lut_10, QINDEX_RANGE,
                  VPX_BITS_10);
  init_me_luts_bd(sad_per_bit16lut_12, sad_per_bit4lut_12, QINDEX_RANGE,
                  VPX_BITS_12);
#endif
}

static const int rd_boost_factor[16] = { 64, 32, 32, 32, 24, 16, 12, 12,
                                         8,  8,  4,  4,  2,  2,  1,  0 };

// Note that the element below for frame type "USE_BUF_FRAME", which indicates
// that the show frame flag is set, should not be used as no real frame
// is encoded so we should not reach here. However, a dummy value
// is inserted here to make sure the data structure has the right number
// of values assigned.
static const int rd_frame_type_factor[FRAME_UPDATE_TYPES] = { 128, 144, 128,
                                                              128, 144, 144 };

// Configure Vizier RD parameters.
// Later this function will use passed in command line values.
void vp9_init_rd_parameters(VP9_COMP *cpi) {
  RD_CONTROL *const rdc = &cpi->rd_ctrl;

  // When |use_vizier_rc_params| is 1, we expect the rd parameters have been
  // initialized by the pass in values.
  // Be careful that parameters below are only initialized to 1, if we do not
  // pass values to them. It is desired to take care of each parameter when
  // using |use_vizier_rc_params|.
  if (cpi->twopass.use_vizier_rc_params) return;

  // Make sure this function is floating point safe.
  vpx_clear_system_state();

  rdc->rd_mult_inter_qp_fac = 1.0;
  rdc->rd_mult_arf_qp_fac = 1.0;
  rdc->rd_mult_key_qp_fac = 1.0;
}

// Returns the default rd multiplier for inter frames for a given qindex.
// The function here is a first pass estimate based on data from
// a previous Vizer run
static double def_inter_rd_multiplier(int qindex) {
  return 4.15 + (0.001 * (double)qindex);
}

// Returns the default rd multiplier for ARF/Golden Frames for a given qindex.
// The function here is a first pass estimate based on data from
// a previous Vizer run
static double def_arf_rd_multiplier(int qindex) {
  return 4.25 + (0.001 * (double)qindex);
}

// Returns the default rd multiplier for key frames for a given qindex.
// The function here is a first pass estimate based on data from
// a previous Vizer run
static double def_kf_rd_multiplier(int qindex) {
  return 4.35 + (0.001 * (double)qindex);
}

int vp9_compute_rd_mult_based_on_qindex(const VP9_COMP *cpi, int qindex) {
  const RD_CONTROL *rdc = &cpi->rd_ctrl;
  const int q = vp9_dc_quant(qindex, 0, cpi->common.bit_depth);
  // largest dc_quant is 21387, therefore rdmult should fit in int32_t
  int rdmult = q * q;

  if (cpi->ext_ratectrl.ready &&
      (cpi->ext_ratectrl.funcs.rc_type & VPX_RC_RDMULT) != 0 &&
      cpi->ext_ratectrl.ext_rdmult != VPX_DEFAULT_RDMULT) {
    return cpi->ext_ratectrl.ext_rdmult;
  }

  // Make sure this function is floating point safe.
  vpx_clear_system_state();

  if (cpi->common.frame_type == KEY_FRAME) {
    double def_rd_q_mult = def_kf_rd_multiplier(qindex);
    rdmult = (int)((double)rdmult * def_rd_q_mult * rdc->rd_mult_key_qp_fac);
  } else if (!cpi->rc.is_src_frame_alt_ref &&
             (cpi->refresh_golden_frame || cpi->refresh_alt_ref_frame)) {
    double def_rd_q_mult = def_arf_rd_multiplier(qindex);
    rdmult = (int)((double)rdmult * def_rd_q_mult * rdc->rd_mult_arf_qp_fac);
  } else {
    double def_rd_q_mult = def_inter_rd_multiplier(qindex);
    rdmult = (int)((double)rdmult * def_rd_q_mult * rdc->rd_mult_inter_qp_fac);
  }

#if CONFIG_VP9_HIGHBITDEPTH
  switch (cpi->common.bit_depth) {
    case VPX_BITS_10: rdmult = ROUND_POWER_OF_TWO(rdmult, 4); break;
    case VPX_BITS_12: rdmult = ROUND_POWER_OF_TWO(rdmult, 8); break;
    default: break;
  }
#endif  // CONFIG_VP9_HIGHBITDEPTH
  return rdmult > 0 ? rdmult : 1;
}

static int modulate_rdmult(const VP9_COMP *cpi, int rdmult) {
  int64_t rdmult_64 = rdmult;
  if (cpi->oxcf.pass == 2 && (cpi->common.frame_type != KEY_FRAME)) {
    const GF_GROUP *const gf_group = &cpi->twopass.gf_group;
    const FRAME_UPDATE_TYPE frame_type = gf_group->update_type[gf_group->index];
    const int gfu_boost = cpi->multi_layer_arf
                              ? gf_group->gfu_boost[gf_group->index]
                              : cpi->rc.gfu_boost;
    const int boost_index = VPXMIN(15, (gfu_boost / 100));

    rdmult_64 = (rdmult_64 * rd_frame_type_factor[frame_type]) >> 7;
    rdmult_64 += ((rdmult_64 * rd_boost_factor[boost_index]) >> 7);
  }
  return (int)rdmult_64;
}

int vp9_compute_rd_mult(const VP9_COMP *cpi, int qindex) {
  int rdmult = vp9_compute_rd_mult_based_on_qindex(cpi, qindex);
  if (cpi->ext_ratectrl.ready &&
      (cpi->ext_ratectrl.funcs.rc_type & VPX_RC_RDMULT) != 0 &&
      cpi->ext_ratectrl.ext_rdmult != VPX_DEFAULT_RDMULT) {
    return cpi->ext_ratectrl.ext_rdmult;
  }
  return modulate_rdmult(cpi, rdmult);
}

int vp9_get_adaptive_rdmult(const VP9_COMP *cpi, double beta) {
  int rdmult =
      vp9_compute_rd_mult_based_on_qindex(cpi, cpi->common.base_qindex);
  rdmult = (int)((double)rdmult / beta);
  rdmult = rdmult > 0 ? rdmult : 1;
  return modulate_rdmult(cpi, rdmult);
}

static int compute_rd_thresh_factor(int qindex, vpx_bit_depth_t bit_depth) {
  double q;
#if CONFIG_VP9_HIGHBITDEPTH
  switch (bit_depth) {
    case VPX_BITS_8: q = vp9_dc_quant(qindex, 0, VPX_BITS_8) / 4.0; break;
    case VPX_BITS_10: q = vp9_dc_quant(qindex, 0, VPX_BITS_10) / 16.0; break;
    default:
      assert(bit_depth == VPX_BITS_12);
      q = vp9_dc_quant(qindex, 0, VPX_BITS_12) / 64.0;
      break;
  }
#else
  (void)bit_depth;
  q = vp9_dc_quant(qindex, 0, VPX_BITS_8) / 4.0;
#endif  // CONFIG_VP9_HIGHBITDEPTH
  // TODO(debargha): Adjust the function below.
  return VPXMAX((int)(pow(q, RD_THRESH_POW) * 5.12), 8);
}

void vp9_initialize_me_consts(VP9_COMP *cpi, MACROBLOCK *x, int qindex) {
#if CONFIG_VP9_HIGHBITDEPTH
  switch (cpi->common.bit_depth) {
    case VPX_BITS_8:
      x->sadperbit16 = sad_per_bit16lut_8[qindex];
      x->sadperbit4 = sad_per_bit4lut_8[qindex];
      break;
    case VPX_BITS_10:
      x->sadperbit16 = sad_per_bit16lut_10[qindex];
      x->sadperbit4 = sad_per_bit4lut_10[qindex];
      break;
    default:
      assert(cpi->common.bit_depth == VPX_BITS_12);
      x->sadperbit16 = sad_per_bit16lut_12[qindex];
      x->sadperbit4 = sad_per_bit4lut_12[qindex];
      break;
  }
#else
  (void)cpi;
  x->sadperbit16 = sad_per_bit16lut_8[qindex];
  x->sadperbit4 = sad_per_bit4lut_8[qindex];
#endif  // CONFIG_VP9_HIGHBITDEPTH
}

static void set_block_thresholds(const VP9_COMMON *cm, RD_OPT *rd) {
  int i, bsize, segment_id;

  for (segment_id = 0; segment_id < MAX_SEGMENTS; ++segment_id) {
    const int qindex =
        clamp(vp9_get_qindex(&cm->seg, segment_id, cm->base_qindex) +
                  cm->y_dc_delta_q,
              0, MAXQ);
    const int q = compute_rd_thresh_factor(qindex, cm->bit_depth);

    for (bsize = 0; bsize < BLOCK_SIZES; ++bsize) {
      // Threshold here seems unnecessarily harsh but fine given actual
      // range of values used for cpi->sf.thresh_mult[].
      const int t = q * rd_thresh_block_size_factor[bsize];
      const int thresh_max = INT_MAX / t;

      if (bsize >= BLOCK_8X8) {
        for (i = 0; i < MAX_MODES; ++i)
          rd->threshes[segment_id][bsize][i] = rd->thresh_mult[i] < thresh_max
                                                   ? rd->thresh_mult[i] * t / 4
                                                   : INT_MAX;
      } else {
        for (i = 0; i < MAX_REFS; ++i)
          rd->threshes[segment_id][bsize][i] =
              rd->thresh_mult_sub8x8[i] < thresh_max
                  ? rd->thresh_mult_sub8x8[i] * t / 4
                  : INT_MAX;
      }
    }
  }
}

void vp9_build_inter_mode_cost(VP9_COMP *cpi) {
  const VP9_COMMON *const cm = &cpi->common;
  int i;
  for (i = 0; i < INTER_MODE_CONTEXTS; ++i) {
    vp9_cost_tokens((int *)cpi->inter_mode_cost[i], cm->fc->inter_mode_probs[i],
                    vp9_inter_mode_tree);
  }
}

void vp9_initialize_rd_consts(VP9_COMP *cpi) {
  VP9_COMMON *const cm = &cpi->common;
  MACROBLOCK *const x = &cpi->td.mb;
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
  RD_OPT *const rd = &cpi->rd;
  int i;

  vpx_clear_system_state();

  rd->RDDIV = RDDIV_BITS;  // In bits (to multiply D by 128).
  rd->RDMULT = vp9_compute_rd_mult(cpi, cm->base_qindex + cm->y_dc_delta_q);

  set_error_per_bit(x, rd->RDMULT);

  x->select_tx_size = (cpi->sf.tx_size_search_method == USE_LARGESTALL &&
                       cm->frame_type != KEY_FRAME)
                          ? 0
                          : 1;

  set_block_thresholds(cm, rd);
  set_partition_probs(cm, xd);

  if (cpi->oxcf.pass == 1) {
    if (!frame_is_intra_only(cm))
      vp9_build_nmv_cost_table(
          x->nmvjointcost,
          cm->allow_high_precision_mv ? x->nmvcost_hp : x->nmvcost,
          &cm->fc->nmvc, cm->allow_high_precision_mv);
  } else {
    if (!cpi->sf.use_nonrd_pick_mode || cm->frame_type == KEY_FRAME)
      fill_token_costs(x->token_costs, cm->fc->coef_probs);

    if (cpi->sf.partition_search_type != VAR_BASED_PARTITION ||
        cm->frame_type == KEY_FRAME) {
      for (i = 0; i < PARTITION_CONTEXTS; ++i)
        vp9_cost_tokens(cpi->partition_cost[i], get_partition_probs(xd, i),
                        vp9_partition_tree);
    }

    if (!cpi->sf.use_nonrd_pick_mode || (cm->current_video_frame & 0x07) == 1 ||
        cm->frame_type == KEY_FRAME) {
      fill_mode_costs(cpi);

      if (!frame_is_intra_only(cm)) {
        vp9_build_nmv_cost_table(
            x->nmvjointcost,
            cm->allow_high_precision_mv ? x->nmvcost_hp : x->nmvcost,
            &cm->fc->nmvc, cm->allow_high_precision_mv);
        vp9_build_inter_mode_cost(cpi);
      }
    }
  }
}

// NOTE: The tables below must be of the same size.

// The functions described below are sampled at the four most significant
// bits of x^2 + 8 / 256.

// Normalized rate:
// This table models the rate for a Laplacian source with given variance
// when quantized with a uniform quantizer with given stepsize. The
// closed form expression is:
// Rn(x) = H(sqrt(r)) + sqrt(r)*[1 + H(r)/(1 - r)],
// where r = exp(-sqrt(2) * x) and x = qpstep / sqrt(variance),
// and H(x) is the binary entropy function.
static const int rate_tab_q10[] = {
  65536, 6086, 5574, 5275, 5063, 4899, 4764, 4651, 4553, 4389, 4255, 4142, 4044,
  3958,  3881, 3811, 3748, 3635, 3538, 3453, 3376, 3307, 3244, 3186, 3133, 3037,
  2952,  2877, 2809, 2747, 2690, 2638, 2589, 2501, 2423, 2353, 2290, 2232, 2179,
  2130,  2084, 2001, 1928, 1862, 1802, 1748, 1698, 1651, 1608, 1530, 1460, 1398,
  1342,  1290, 1243, 1199, 1159, 1086, 1021, 963,  911,  864,  821,  781,  745,
  680,   623,  574,  530,  490,  455,  424,  395,  345,  304,  269,  239,  213,
  190,   171,  154,  126,  104,  87,   73,   61,   52,   44,   38,   28,   21,
  16,    12,   10,   8,    6,    5,    3,    2,    1,    1,    1,    0,    0,
};

// Normalized distortion:
// This table models the normalized distortion for a Laplacian source
// with given variance when quantized with a uniform quantizer
// with given stepsize. The closed form expression is:
// Dn(x) = 1 - 1/sqrt(2) * x / sinh(x/sqrt(2))
// where x = qpstep / sqrt(variance).
// Note the actual distortion is Dn * variance.
static const int dist_tab_q10[] = {
  0,    0,    1,    1,    1,    2,    2,    2,    3,    3,    4,    5,    5,
  6,    7,    7,    8,    9,    11,   12,   13,   15,   16,   17,   18,   21,
  24,   26,   29,   31,   34,   36,   39,   44,   49,   54,   59,   64,   69,
  73,   78,   88,   97,   106,  115,  124,  133,  142,  151,  167,  184,  200,
  215,  231,  245,  260,  274,  301,  327,  351,  375,  397,  418,  439,  458,
  495,  528,  559,  587,  613,  637,  659,  680,  717,  749,  777,  801,  823,
  842,  859,  874,  899,  919,  936,  949,  960,  969,  977,  983,  994,  1001,
  1006, 1010, 1013, 1015, 1017, 1018, 1020, 1022, 1022, 1023, 1023, 1023, 1024,
};
static const int xsq_iq_q10[] = {
  0,      4,      8,      12,     16,     20,     24,     28,     32,
  40,     48,     56,     64,     72,     80,     88,     96,     112,
  128,    144,    160,    176,    192,    208,    224,    256,    288,
  320,    352,    384,    416,    448,    480,    544,    608,    672,
  736,    800,    864,    928,    992,    1120,   1248,   1376,   1504,
  1632,   1760,   1888,   2016,   2272,   2528,   2784,   3040,   3296,
  3552,   3808,   4064,   4576,   5088,   5600,   6112,   6624,   7136,
  7648,   8160,   9184,   10208,  11232,  12256,  13280,  14304,  15328,
  16352,  18400,  20448,  22496,  24544,  26592,  28640,  30688,  32736,
  36832,  40928,  45024,  49120,  53216,  57312,  61408,  65504,  73696,
  81888,  90080,  98272,  106464, 114656, 122848, 131040, 147424, 163808,
  180192, 196576, 212960, 229344, 245728,
};

static void model_rd_norm(int xsq_q10, int *r_q10, int *d_q10) {
  const int tmp = (xsq_q10 >> 2) + 8;
  const int k = get_msb(tmp) - 3;
  const int xq = (k << 3) + ((tmp >> k) & 0x7);
  const int one_q10 = 1 << 10;
  const int a_q10 = ((xsq_q10 - xsq_iq_q10[xq]) << 10) >> (2 + k);
  const int b_q10 = one_q10 - a_q10;
  *r_q10 = (rate_tab_q10[xq] * b_q10 + rate_tab_q10[xq + 1] * a_q10) >> 10;
  *d_q10 = (dist_tab_q10[xq] * b_q10 + dist_tab_q10[xq + 1] * a_q10) >> 10;
}

static const uint32_t MAX_XSQ_Q10 = 245727;

void vp9_model_rd_from_var_lapndz(unsigned int var, unsigned int n_log2,
                                  unsigned int qstep, int *rate,
                                  int64_t *dist) {
  // This function models the rate and distortion for a Laplacian
  // source with given variance when quantized with a uniform quantizer
  // with given stepsize. The closed form expressions are in:
  // Hang and Chen, "Source Model for transform video coder and its
  // application - Part I: Fundamental Theory", IEEE Trans. Circ.
  // Sys. for Video Tech., April 1997.
  if (var == 0) {
    *rate = 0;
    *dist = 0;
  } else {
    int d_q10, r_q10;
    const uint64_t xsq_q10_64 =
        (((uint64_t)qstep * qstep << (n_log2 + 10)) + (var >> 1)) / var;
    const int xsq_q10 = (int)VPXMIN(xsq_q10_64, MAX_XSQ_Q10);
    model_rd_norm(xsq_q10, &r_q10, &d_q10);
    *rate = ROUND_POWER_OF_TWO(r_q10 << n_log2, 10 - VP9_PROB_COST_SHIFT);
    *dist = (var * (int64_t)d_q10 + 512) >> 10;
  }
}

// Disable gcc 12.2 false positive warning.
// warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-overflow"
#endif
void vp9_get_entropy_contexts(BLOCK_SIZE bsize, TX_SIZE tx_size,
                              const struct macroblockd_plane *pd,
                              ENTROPY_CONTEXT t_above[16],
                              ENTROPY_CONTEXT t_left[16]) {
  const BLOCK_SIZE plane_bsize = get_plane_block_size(bsize, pd);
  const int num_4x4_w = num_4x4_blocks_wide_lookup[plane_bsize];
  const int num_4x4_h = num_4x4_blocks_high_lookup[plane_bsize];
  const ENTROPY_CONTEXT *const above = pd->above_context;
  const ENTROPY_CONTEXT *const left = pd->left_context;

  int i;
  switch (tx_size) {
    case TX_4X4:
      memcpy(t_above, above, sizeof(ENTROPY_CONTEXT) * num_4x4_w);
      memcpy(t_left, left, sizeof(ENTROPY_CONTEXT) * num_4x4_h);
      break;
    case TX_8X8:
      for (i = 0; i < num_4x4_w; i += 2)
        t_above[i] = !!*(const uint16_t *)&above[i];
      for (i = 0; i < num_4x4_h; i += 2)
        t_left[i] = !!*(const uint16_t *)&left[i];
      break;
    case TX_16X16:
      for (i = 0; i < num_4x4_w; i += 4)
        t_above[i] = !!*(const uint32_t *)&above[i];
      for (i = 0; i < num_4x4_h; i += 4)
        t_left[i] = !!*(const uint32_t *)&left[i];
      break;
    default:
      assert(tx_size == TX_32X32);
      for (i = 0; i < num_4x4_w; i += 8)
        t_above[i] = !!*(const uint64_t *)&above[i];
      for (i = 0; i < num_4x4_h; i += 8)
        t_left[i] = !!*(const uint64_t *)&left[i];
      break;
  }
}
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif

void vp9_mv_pred(VP9_COMP *cpi, MACROBLOCK *x, uint8_t *ref_y_buffer,
                 int ref_y_stride, int ref_frame, BLOCK_SIZE block_size) {
  int i;
  int zero_seen = 0;
  int best_index = 0;
  int best_sad = INT_MAX;
  int this_sad = INT_MAX;
  int max_mv = 0;
  int near_same_nearest;
  uint8_t *src_y_ptr = x->plane[0].src.buf;
  uint8_t *ref_y_ptr;
  const int num_mv_refs =
      MAX_MV_REF_CANDIDATES + (block_size < x->max_partition_size);

  MV pred_mv[3];
  pred_mv[0] = x->mbmi_ext->ref_mvs[ref_frame][0].as_mv;
  pred_mv[1] = x->mbmi_ext->ref_mvs[ref_frame][1].as_mv;
  pred_mv[2] = x->pred_mv[ref_frame];
  assert(num_mv_refs <= (int)(sizeof(pred_mv) / sizeof(pred_mv[0])));

  near_same_nearest = x->mbmi_ext->ref_mvs[ref_frame][0].as_int ==
                      x->mbmi_ext->ref_mvs[ref_frame][1].as_int;

  // Get the sad for each candidate reference mv.
  for (i = 0; i < num_mv_refs; ++i) {
    const MV *this_mv = &pred_mv[i];
    int fp_row, fp_col;
    if (this_mv->row == INT16_MAX || this_mv->col == INT16_MAX) continue;
    if (i == 1 && near_same_nearest) continue;
    fp_row = (this_mv->row + 3 + (this_mv->row >= 0)) >> 3;
    fp_col = (this_mv->col + 3 + (this_mv->col >= 0)) >> 3;
    max_mv = VPXMAX(max_mv, VPXMAX(abs(this_mv->row), abs(this_mv->col)) >> 3);

    if (fp_row == 0 && fp_col == 0 && zero_seen) continue;
    zero_seen |= (fp_row == 0 && fp_col == 0);

    ref_y_ptr = &ref_y_buffer[ref_y_stride * fp_row + fp_col];
    // Find sad for current vector.
    this_sad = cpi->fn_ptr[block_size].sdf(src_y_ptr, x->plane[0].src.stride,
                                           ref_y_ptr, ref_y_stride);
    // Note if it is the best so far.
    if (this_sad < best_sad) {
      best_sad = this_sad;
      best_index = i;
    }
  }

  // Note the index of the mv that worked best in the reference list.
  x->mv_best_ref_index[ref_frame] = best_index;
  x->max_mv_context[ref_frame] = max_mv;
  x->pred_mv_sad[ref_frame] = best_sad;
}

void vp9_setup_pred_block(const MACROBLOCKD *xd,
                          struct buf_2d dst[MAX_MB_PLANE],
                          const YV12_BUFFER_CONFIG *src, int mi_row, int mi_col,
                          const struct scale_factors *scale,
                          const struct scale_factors *scale_uv) {
  int i;

  dst[0].buf = src->y_buffer;
  dst[0].stride = src->y_stride;
  dst[1].buf = src->u_buffer;
  dst[2].buf = src->v_buffer;
  dst[1].stride = dst[2].stride = src->uv_stride;

  for (i = 0; i < MAX_MB_PLANE; ++i) {
    setup_pred_plane(dst + i, dst[i].buf, dst[i].stride, mi_row, mi_col,
                     i ? scale_uv : scale, xd->plane[i].subsampling_x,
                     xd->plane[i].subsampling_y);
  }
}

int vp9_raster_block_offset(BLOCK_SIZE plane_bsize, int raster_block,
                            int stride) {
  const int bw = b_width_log2_lookup[plane_bsize];
  const int y = 4 * (raster_block >> bw);
  const int x = 4 * (raster_block & ((1 << bw) - 1));
  return y * stride + x;
}

int16_t *vp9_raster_block_offset_int16(BLOCK_SIZE plane_bsize, int raster_block,
                                       int16_t *base) {
  const int stride = 4 * num_4x4_blocks_wide_lookup[plane_bsize];
  return base + vp9_raster_block_offset(plane_bsize, raster_block, stride);
}

YV12_BUFFER_CONFIG *vp9_get_scaled_ref_frame(const VP9_COMP *cpi,
                                             int ref_frame) {
  const VP9_COMMON *const cm = &cpi->common;
  const int scaled_idx = cpi->scaled_ref_idx[ref_frame - 1];
  const int ref_idx = get_ref_frame_buf_idx(cpi, ref_frame);
  assert(ref_frame >= LAST_FRAME && ref_frame <= ALTREF_FRAME);
  return (scaled_idx != ref_idx && scaled_idx != INVALID_IDX)
             ? &cm->buffer_pool->frame_bufs[scaled_idx].buf
             : NULL;
}

int vp9_get_switchable_rate(const VP9_COMP *cpi, const MACROBLOCKD *const xd) {
  const MODE_INFO *const mi = xd->mi[0];
  const int ctx = get_pred_context_switchable_interp(xd);
  return SWITCHABLE_INTERP_RATE_FACTOR *
         cpi->switchable_interp_costs[ctx][mi->interp_filter];
}

void vp9_set_rd_speed_thresholds(VP9_COMP *cpi) {
  int i;
  RD_OPT *const rd = &cpi->rd;
  SPEED_FEATURES *const sf = &cpi->sf;

  // Set baseline threshold values.
  for (i = 0; i < MAX_MODES; ++i)
    rd->thresh_mult[i] = cpi->oxcf.mode == BEST ? -500 : 0;

  if (sf->adaptive_rd_thresh) {
    rd->thresh_mult[THR_NEARESTMV] = 300;
    rd->thresh_mult[THR_NEARESTG] = 300;
    rd->thresh_mult[THR_NEARESTA] = 300;
  } else {
    rd->thresh_mult[THR_NEARESTMV] = 0;
    rd->thresh_mult[THR_NEARESTG] = 0;
    rd->thresh_mult[THR_NEARESTA] = 0;
  }

  rd->thresh_mult[THR_DC] += 1000;

  rd->thresh_mult[THR_NEWMV] += 1000;
  rd->thresh_mult[THR_NEWA] += 1000;
  rd->thresh_mult[THR_NEWG] += 1000;

  rd->thresh_mult[THR_NEARMV] += 1000;
  rd->thresh_mult[THR_NEARA] += 1000;
  rd->thresh_mult[THR_COMP_NEARESTLA] += 1000;
  rd->thresh_mult[THR_COMP_NEARESTGA] += 1000;

  rd->thresh_mult[THR_TM] += 1000;

  rd->thresh_mult[THR_COMP_NEARLA] += 1500;
  rd->thresh_mult[THR_COMP_NEWLA] += 2000;
  rd->thresh_mult[THR_NEARG] += 1000;
  rd->thresh_mult[THR_COMP_NEARGA] += 1500;
  rd->thresh_mult[THR_COMP_NEWGA] += 2000;

  rd->thresh_mult[THR_ZEROMV] += 2000;
  rd->thresh_mult[THR_ZEROG] += 2000;
  rd->thresh_mult[THR_ZEROA] += 2000;
  rd->thresh_mult[THR_COMP_ZEROLA] += 2500;
  rd->thresh_mult[THR_COMP_ZEROGA] += 2500;

  rd->thresh_mult[THR_H_PRED] += 2000;
  rd->thresh_mult[THR_V_PRED] += 2000;
  rd->thresh_mult[THR_D45_PRED] += 2500;
  rd->thresh_mult[THR_D135_PRED] += 2500;
  rd->thresh_mult[THR_D117_PRED] += 2500;
  rd->thresh_mult[THR_D153_PRED] += 2500;
  rd->thresh_mult[THR_D207_PRED] += 2500;
  rd->thresh_mult[THR_D63_PRED] += 2500;
}

void vp9_set_rd_speed_thresholds_sub8x8(VP9_COMP *cpi) {
  static const int thresh_mult[2][MAX_REFS] = {
    { 2500, 2500, 2500, 4500, 4500, 2500 },
    { 2000, 2000, 2000, 4000, 4000, 2000 }
  };
  RD_OPT *const rd = &cpi->rd;
  const int idx = cpi->oxcf.mode == BEST;
  memcpy(rd->thresh_mult_sub8x8, thresh_mult[idx], sizeof(thresh_mult[idx]));
}

void vp9_update_rd_thresh_fact(int (*factor_buf)[MAX_MODES], int rd_thresh,
                               int bsize, int best_mode_index) {
  if (rd_thresh > 0) {
    const int top_mode = bsize < BLOCK_8X8 ? MAX_REFS : MAX_MODES;
    int mode;
    for (mode = 0; mode < top_mode; ++mode) {
      const BLOCK_SIZE min_size = VPXMAX(bsize - 1, BLOCK_4X4);
      const BLOCK_SIZE max_size = VPXMIN(bsize + 2, BLOCK_64X64);
      BLOCK_SIZE bs;
      for (bs = min_size; bs <= max_size; ++bs) {
        int *const fact = &factor_buf[bs][mode];
        if (mode == best_mode_index) {
          *fact -= (*fact >> 4);
        } else {
          *fact = VPXMIN(*fact + RD_THRESH_INC, rd_thresh * RD_THRESH_MAX_FACT);
        }
      }
    }
  }
}

int vp9_get_intra_cost_penalty(const VP9_COMP *const cpi, BLOCK_SIZE bsize,
                               int qindex, int qdelta) {
  // Reduce the intra cost penalty for small blocks (<=16x16).
  int reduction_fac =
      (bsize <= BLOCK_16X16) ? ((bsize <= BLOCK_8X8) ? 4 : 2) : 0;

  if (cpi->noise_estimate.enabled && cpi->noise_estimate.level == kHigh)
    // Don't reduce intra cost penalty if estimated noise level is high.
    reduction_fac = 0;

  // Always use VPX_BITS_8 as input here because the penalty is applied
  // to rate not distortion so we want a consistent penalty for all bit
  // depths. If the actual bit depth were passed in here then the value
  // retured by vp9_dc_quant() would scale with the bit depth and we would
  // then need to apply inverse scaling to correct back to a bit depth
  // independent rate penalty.
  return (20 * vp9_dc_quant(qindex, qdelta, VPX_BITS_8)) >> reduction_fac;
}