/*

 * 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 <assert.h>

#include <limits.h>

#include <math.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "aom_dsp/aom_dsp_common.h"

#include "aom_mem/aom_mem.h"

#include "aom_ports/mem.h"

#include "aom_ports/aom_once.h"

#include "av1/common/alloccommon.h"

#include "av1/encoder/aq_cyclicrefresh.h"

#include "av1/common/common.h"

#include "av1/common/entropymode.h"

#include "av1/common/quant_common.h"

#include "av1/common/seg_common.h"

#include "av1/encoder/encodemv.h"

#include "av1/encoder/encoder_utils.h"

#include "av1/encoder/encode_strategy.h"

#include "av1/encoder/gop_structure.h"

#include "av1/encoder/mcomp.h"

#include "av1/encoder/random.h"

#include "av1/encoder/ratectrl.h"

#include "config/aom_dsp_rtcd.h"

#define USE_UNRESTRICTED_Q_IN_CQ_MODE 0

// Max rate target for 1080P and below encodes under normal circumstances

// (1920 * 1080 / (16 * 16)) * MAX_MB_RATE bits per MB

#define MAX_MB_RATE 250

#define MAXRATE_1080P 2025000

#define MIN_BPB_FACTOR 0.005

#define MAX_BPB_FACTOR 50

#define SUPERRES_QADJ_PER_DENOM_KEYFRAME_SOLO 0

#define SUPERRES_QADJ_PER_DENOM_KEYFRAME 2

#define SUPERRES_QADJ_PER_DENOM_ARFFRAME 0

#define FRAME_OVERHEAD_BITS 200

#define ASSIGN_MINQ_TABLE(bit_depth, name)                   \

  do {                                                       \

    switch (bit_depth) {                                     \

      case AOM_BITS_8: name = name##_8; break;               \

      case AOM_BITS_10: name = name##_10; break;             \

      case AOM_BITS_12: name = name##_12; break;             \

      default:                                               \

        assert(0 &&                                          \

               "bit_depth should be AOM_BITS_8, AOM_BITS_10" \

               " or AOM_BITS_12");                           \

        name = NULL;                                         \

    }                                                        \

  } while (0)

// Tables relating active max Q to active min Q

static int kf_low_motion_minq_8[QINDEX_RANGE];

static int kf_high_motion_minq_8[QINDEX_RANGE];

static int arfgf_low_motion_minq_8[QINDEX_RANGE];

static int arfgf_high_motion_minq_8[QINDEX_RANGE];

static int inter_minq_8[QINDEX_RANGE];

static int rtc_minq_8[QINDEX_RANGE];

static int kf_low_motion_minq_10[QINDEX_RANGE];

static int kf_high_motion_minq_10[QINDEX_RANGE];

static int arfgf_low_motion_minq_10[QINDEX_RANGE];

static int arfgf_high_motion_minq_10[QINDEX_RANGE];

static int inter_minq_10[QINDEX_RANGE];

static int rtc_minq_10[QINDEX_RANGE];

static int kf_low_motion_minq_12[QINDEX_RANGE];

static int kf_high_motion_minq_12[QINDEX_RANGE];

static int arfgf_low_motion_minq_12[QINDEX_RANGE];

static int arfgf_high_motion_minq_12[QINDEX_RANGE];

static int inter_minq_12[QINDEX_RANGE];

static int rtc_minq_12[QINDEX_RANGE];

static int gf_high = 2400;

static int gf_low = 300;

#ifdef STRICT_RC

static int kf_high = 3200;

#else

static int kf_high = 5000;

#endif

static int kf_low = 400;

// How many times less pixels there are to encode given the current scaling.

// Temporary replacement for rcf_mult and rate_thresh_mult.

static double resize_rate_factor(const FrameDimensionCfg *const frm_dim_cfg,

                                 int width, int height) {

  return (double)(frm_dim_cfg->width * frm_dim_cfg->height) / (width * height);

}

// Functions to compute the active minq lookup table entries based on a

// formulaic approach to facilitate easier adjustment of the Q tables.

// The formulae were derived from computing a 3rd order polynomial best

// fit to the original data (after plotting real maxq vs minq (not q index))

static int get_minq_index(double maxq, double x3, double x2, double x1,

                          aom_bit_depth_t bit_depth) {

  const double minqtarget = AOMMIN(((x3 * maxq + x2) * maxq + x1) * maxq, maxq);

  // Special case handling to deal with the step from q2.0

  // down to lossless mode represented by q 1.0.

  if (minqtarget <= 2.0) return 0;

  return av1_find_qindex(minqtarget, bit_depth, 0, QINDEX_RANGE - 1);

}

static void init_minq_luts(int *kf_low_m, int *kf_high_m, int *arfgf_low,

                           int *arfgf_high, int *inter, int *rtc,

                           aom_bit_depth_t bit_depth) {

  int i;

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

    const double maxq = av1_convert_qindex_to_q(i, bit_depth);

    kf_low_m[i] = get_minq_index(maxq, 0.000001, -0.0004, 0.150, bit_depth);

    kf_high_m[i] = get_minq_index(maxq, 0.0000021, -0.00125, 0.45, bit_depth);

    arfgf_low[i] = get_minq_index(maxq, 0.0000015, -0.0009, 0.30, bit_depth);

    arfgf_high[i] = get_minq_index(maxq, 0.0000021, -0.00125, 0.55, bit_depth);

    inter[i] = get_minq_index(maxq, 0.00000271, -0.00113, 0.90, bit_depth);

    rtc[i] = get_minq_index(maxq, 0.00000271, -0.00113, 0.70, bit_depth);

  }

}

static void rc_init_minq_luts(void) {

  init_minq_luts(kf_low_motion_minq_8, kf_high_motion_minq_8,

                 arfgf_low_motion_minq_8, arfgf_high_motion_minq_8,

                 inter_minq_8, rtc_minq_8, AOM_BITS_8);

  init_minq_luts(kf_low_motion_minq_10, kf_high_motion_minq_10,

                 arfgf_low_motion_minq_10, arfgf_high_motion_minq_10,

                 inter_minq_10, rtc_minq_10, AOM_BITS_10);

  init_minq_luts(kf_low_motion_minq_12, kf_high_motion_minq_12,

                 arfgf_low_motion_minq_12, arfgf_high_motion_minq_12,

                 inter_minq_12, rtc_minq_12, AOM_BITS_12);

}

void av1_rc_init_minq_luts(void) { aom_once(rc_init_minq_luts); }

// These functions use formulaic calculations to make playing with the

// quantizer tables easier. If necessary they can be replaced by lookup

// tables if and when things settle down in the experimental bitstream

double av1_convert_qindex_to_q(int qindex, aom_bit_depth_t bit_depth) {

  // Convert the index to a real Q value (scaled down to match old Q values)

  switch (bit_depth) {

    case AOM_BITS_8: return av1_ac_quant_QTX(qindex, 0, bit_depth) / 4.0;

    case AOM_BITS_10: return av1_ac_quant_QTX(qindex, 0, bit_depth) / 16.0;

    case AOM_BITS_12: return av1_ac_quant_QTX(qindex, 0, bit_depth) / 64.0;

    default:

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

      return -1.0;

  }

}

int av1_convert_q_to_qindex(double q, aom_bit_depth_t bit_depth) {

  int qindex = MINQ;

  // Find the first qindex that matches or exceeds q.

  // Note: this operation can also be done with a binary search, as

  // av1_convert_qindex_to_q() is monotonically increasing with respect to

  // increasing qindex.

  while (qindex < MAXQ && av1_convert_qindex_to_q(qindex, bit_depth) < q) {

    qindex++;

  }

  return qindex;

}

// Gets the appropriate bpmb enumerator based on the frame and content type

static int get_bpmb_enumerator(FRAME_TYPE frame_type,

                               const int is_screen_content_type) {

  int enumerator;

  if (is_screen_content_type) {

    enumerator = (frame_type == KEY_FRAME) ? 1000000 : 750000;

  } else {

    enumerator = (frame_type == KEY_FRAME) ? 2000000 : 1500000;

  }

  return enumerator;

}

static int get_init_ratio(double sse) { return (int)(300000 / sse); }

// Adjustment based on spatial content and last encoded keyframe.

// Allow for increase in enumerator to reduce overshoot.

static int adjust_rtc_keyframe(const RATE_CONTROL *rc, int enumerator) {

  // Don't adjust if most of the image is flat.

  if (rc->perc_spatial_flat_blocks > 70) return enumerator;

  if (rc->last_encoded_size_keyframe == 0 ||

      rc->frames_since_scene_change < rc->frames_since_key) {

    // Very first frame, or if scene change happened after last keyframe.

    if (rc->frame_spatial_variance > 1000 ||

        (rc->frame_spatial_variance > 500 && rc->perc_spatial_flat_blocks == 0))

      return enumerator << 3;

    else if (rc->frame_spatial_variance > 500 &&

             rc->perc_spatial_flat_blocks < 10)

      return enumerator << 2;

    else if (rc->frame_spatial_variance > 400)

      return enumerator << 1;

  } else if (rc->frames_since_scene_change >= rc->frames_since_key) {

    // There was no scene change before previous encoded keyframe, so

    // use the last_encoded/target_size_keyframe.

    if (rc->last_encoded_size_keyframe > 4 * rc->last_target_size_keyframe &&

        rc->frame_spatial_variance > 500)

      return enumerator << 3;

    else if (rc->last_encoded_size_keyframe >

                 2 * rc->last_target_size_keyframe &&

             rc->frame_spatial_variance > 200)

      return enumerator << 2;

    else if (rc->last_encoded_size_keyframe > rc->last_target_size_keyframe)

      return enumerator << 1;

  }

  return enumerator;

}

int av1_rc_bits_per_mb(const AV1_COMP *cpi, FRAME_TYPE frame_type, int qindex,

                       double correction_factor, int accurate_estimate) {

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

  const int is_screen_content_type = cpi->is_screen_content_type;

  const aom_bit_depth_t bit_depth = cm->seq_params->bit_depth;

  const double q = av1_convert_qindex_to_q(qindex, bit_depth);

  int enumerator = get_bpmb_enumerator(frame_type, is_screen_content_type);

  assert(correction_factor <= MAX_BPB_FACTOR &&

         correction_factor >= MIN_BPB_FACTOR);

  if (cpi->oxcf.rc_cfg.mode == AOM_CBR && frame_type != KEY_FRAME &&

      accurate_estimate && cpi->rec_sse != UINT64_MAX) {

    const int mbs = cm->mi_params.MBs;

    const double sse_sqrt =

        (double)((int)sqrt((double)(cpi->rec_sse)) << BPER_MB_NORMBITS) /

        (double)mbs;

    const int ratio = (cpi->rc.bit_est_ratio == 0) ? get_init_ratio(sse_sqrt)

                                                   : cpi->rc.bit_est_ratio;

    // Clamp the enumerator to lower the q fluctuations.

    enumerator = clamp((int)(ratio * sse_sqrt), 20000, 170000);

  } else if (cpi->oxcf.rc_cfg.mode == AOM_CBR && frame_type == KEY_FRAME &&

             cpi->sf.rt_sf.rc_adjust_keyframe && bit_depth == 8 &&

             cpi->oxcf.rc_cfg.max_intra_bitrate_pct > 0 &&

             cpi->svc.spatial_layer_id == 0) {

    enumerator = adjust_rtc_keyframe(&cpi->rc, enumerator);

  }

  // q based adjustment to baseline enumerator

  return (int)(enumerator * correction_factor / q);

}

int av1_estimate_bits_at_q(const AV1_COMP *cpi, int q,

                           double correction_factor) {

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

  const FRAME_TYPE frame_type = cm->current_frame.frame_type;

  const int mbs = cm->mi_params.MBs;

  const int bpm =

      (int)(av1_rc_bits_per_mb(cpi, frame_type, q, correction_factor,

                               cpi->sf.hl_sf.accurate_bit_estimate));

  return AOMMAX(FRAME_OVERHEAD_BITS,

                (int)((uint64_t)bpm * mbs) >> BPER_MB_NORMBITS);

}

static int clamp_pframe_target_size(const AV1_COMP *const cpi, int64_t target,

                                    FRAME_UPDATE_TYPE frame_update_type) {

  const RATE_CONTROL *rc = &cpi->rc;

  const RateControlCfg *const rc_cfg = &cpi->oxcf.rc_cfg;

  const int min_frame_target =

      AOMMAX(rc->min_frame_bandwidth, rc->avg_frame_bandwidth >> 5);

  // Clip the frame target to the minimum setup value.

  if (frame_update_type == OVERLAY_UPDATE ||

      frame_update_type == INTNL_OVERLAY_UPDATE) {

    // If there is an active ARF at this location use the minimum

    // bits on this frame even if it is a constructed arf.

    // The active maximum quantizer insures that an appropriate

    // number of bits will be spent if needed for constructed ARFs.

    target = min_frame_target;

  } else if (target < min_frame_target) {

    target = min_frame_target;

  }

  // Clip the frame target to the maximum allowed value.

  if (target > rc->max_frame_bandwidth) target = rc->max_frame_bandwidth;

  if (rc_cfg->max_inter_bitrate_pct) {

    const int64_t max_rate =

        (int64_t)rc->avg_frame_bandwidth * rc_cfg->max_inter_bitrate_pct / 100;

    target = AOMMIN(target, max_rate);

  }

  return (int)target;

}

static int clamp_iframe_target_size(const AV1_COMP *const cpi, int64_t target) {

  const RATE_CONTROL *rc = &cpi->rc;

  const RateControlCfg *const rc_cfg = &cpi->oxcf.rc_cfg;

  if (rc_cfg->max_intra_bitrate_pct) {

    const int64_t max_rate =

        (int64_t)rc->avg_frame_bandwidth * rc_cfg->max_intra_bitrate_pct / 100;

    target = AOMMIN(target, max_rate);

  }

  if (target > rc->max_frame_bandwidth) target = rc->max_frame_bandwidth;

  return (int)target;

}

// Update the buffer level for higher temporal layers, given the encoded current

// temporal layer.

static void update_layer_buffer_level(SVC *svc, int encoded_frame_size,

                                      bool is_screen) {

  const int current_temporal_layer = svc->temporal_layer_id;

  for (int i = current_temporal_layer + 1; i < svc->number_temporal_layers;

       ++i) {

    const int layer =

        LAYER_IDS_TO_IDX(svc->spatial_layer_id, i, svc->number_temporal_layers);

    LAYER_CONTEXT *lc = &svc->layer_context[layer];

    PRIMARY_RATE_CONTROL *lp_rc = &lc->p_rc;

    lp_rc->bits_off_target +=

        (int)round(lc->target_bandwidth / lc->framerate) - encoded_frame_size;

    // Clip buffer level to maximum buffer size for the layer.

    lp_rc->bits_off_target =

        AOMMIN(lp_rc->bits_off_target, lp_rc->maximum_buffer_size);

    lp_rc->buffer_level = lp_rc->bits_off_target;

    // For screen-content mode: don't let buffer level go below threshold,

    // given here as -rc->maximum_ buffer_size, to allow buffer to come back

    // up sooner after slide change with big overshoot.

    if (is_screen) {

      lp_rc->bits_off_target =

          AOMMAX(lp_rc->bits_off_target, -lp_rc->maximum_buffer_size);

      lp_rc->buffer_level = lp_rc->bits_off_target;

    }

  }

}

// Update the buffer level: leaky bucket model.

static void update_buffer_level(AV1_COMP *cpi, int encoded_frame_size) {

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

  RATE_CONTROL *const rc = &cpi->rc;

  PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

  // Non-viewable frames are a special case and are treated as pure overhead.

  if (!cm->show_frame)

    p_rc->bits_off_target -= encoded_frame_size;

  else

    p_rc->bits_off_target += rc->avg_frame_bandwidth - encoded_frame_size;

  // Clip the buffer level to the maximum specified buffer size.

  p_rc->bits_off_target =

      AOMMIN(p_rc->bits_off_target, p_rc->maximum_buffer_size);

  // For screen-content mode: don't let buffer level go below threshold,

  // given here as -rc->maximum_ buffer_size, to allow buffer to come back

  // up sooner after slide change with big overshoot.

  if (cpi->oxcf.tune_cfg.content == AOM_CONTENT_SCREEN)

    p_rc->bits_off_target =

        AOMMAX(p_rc->bits_off_target, -p_rc->maximum_buffer_size);

  p_rc->buffer_level = p_rc->bits_off_target;

  if (cpi->ppi->use_svc)

    update_layer_buffer_level(&cpi->svc, encoded_frame_size,

                              cpi->oxcf.tune_cfg.content == AOM_CONTENT_SCREEN);

#if CONFIG_FPMT_TEST

  /* The variable temp_buffer_level is introduced for quality

   * simulation purpose, it retains the value previous to the parallel

   * encode frames. The variable is updated based on the update flag.

   *

   * If there exist show_existing_frames between parallel frames, then to

   * retain the temp state do not update it. */

  int show_existing_between_parallel_frames =

      (cpi->ppi->gf_group.update_type[cpi->gf_frame_index] ==

           INTNL_OVERLAY_UPDATE &&

       cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index + 1] == 2);

  if (cpi->do_frame_data_update && !show_existing_between_parallel_frames &&

      cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE) {

    p_rc->temp_buffer_level = p_rc->buffer_level;

  }

#endif

}

int av1_rc_get_default_min_gf_interval(int width, int height,

                                       double framerate) {

  // Assume we do not need any constraint lower than 4K 20 fps

  static const double factor_safe = 3840 * 2160 * 20.0;

  const double factor = (double)width * height * framerate;

  const int default_interval =

      clamp((int)(framerate * 0.125), MIN_GF_INTERVAL, MAX_GF_INTERVAL);

  if (factor <= factor_safe)

    return default_interval;

  else

    return AOMMAX(default_interval,

                  (int)(MIN_GF_INTERVAL * factor / factor_safe + 0.5));

  // Note this logic makes:

  // 4K24: 5

  // 4K30: 6

  // 4K60: 12

}

// Note get_default_max_gf_interval() requires the min_gf_interval to

// be passed in to ensure that the max_gf_interval returned is at least as big

// as that.

static int get_default_max_gf_interval(double framerate, int min_gf_interval) {

  int interval = AOMMIN(MAX_GF_INTERVAL, (int)(framerate * 0.75));

  interval += (interval & 0x01);  // Round to even value

  interval = AOMMAX(MAX_GF_INTERVAL, interval);

  return AOMMAX(interval, min_gf_interval);

}

void av1_primary_rc_init(const AV1EncoderConfig *oxcf,

                         PRIMARY_RATE_CONTROL *p_rc) {

  const RateControlCfg *const rc_cfg = &oxcf->rc_cfg;

  int worst_allowed_q = rc_cfg->worst_allowed_q;

  int min_gf_interval = oxcf->gf_cfg.min_gf_interval;

  int max_gf_interval = oxcf->gf_cfg.max_gf_interval;

  if (min_gf_interval == 0)

    min_gf_interval = av1_rc_get_default_min_gf_interval(

        oxcf->frm_dim_cfg.width, oxcf->frm_dim_cfg.height,

        oxcf->input_cfg.init_framerate);

  if (max_gf_interval == 0)

    max_gf_interval = get_default_max_gf_interval(

        oxcf->input_cfg.init_framerate, min_gf_interval);

  p_rc->baseline_gf_interval = (min_gf_interval + max_gf_interval) / 2;

  p_rc->this_key_frame_forced = 0;

  p_rc->next_key_frame_forced = 0;

  p_rc->ni_frames = 0;

  p_rc->tot_q = 0.0;

  p_rc->total_actual_bits = 0;

  p_rc->total_target_bits = 0;

  p_rc->buffer_level = p_rc->starting_buffer_level;

  if (oxcf->target_seq_level_idx[0] < SEQ_LEVELS) {

    worst_allowed_q = 255;

  }

  if (oxcf->pass == AOM_RC_ONE_PASS && rc_cfg->mode == AOM_CBR) {

    p_rc->avg_frame_qindex[KEY_FRAME] = worst_allowed_q;

    p_rc->avg_frame_qindex[INTER_FRAME] = worst_allowed_q;

  } else {

    p_rc->avg_frame_qindex[KEY_FRAME] =

        (worst_allowed_q + rc_cfg->best_allowed_q) / 2;

    p_rc->avg_frame_qindex[INTER_FRAME] =

        (worst_allowed_q + rc_cfg->best_allowed_q) / 2;

  }

  p_rc->avg_q = av1_convert_qindex_to_q(rc_cfg->worst_allowed_q,

                                        oxcf->tool_cfg.bit_depth);

  p_rc->last_q[KEY_FRAME] = rc_cfg->best_allowed_q;

  p_rc->last_q[INTER_FRAME] = rc_cfg->worst_allowed_q;

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

    p_rc->rate_correction_factors[i] = 0.7;

  }

  p_rc->rate_correction_factors[KF_STD] = 1.0;

  p_rc->bits_off_target = p_rc->starting_buffer_level;

  p_rc->rolling_target_bits = AOMMAX(

      1, (int)(oxcf->rc_cfg.target_bandwidth / oxcf->input_cfg.init_framerate));

  p_rc->rolling_actual_bits = AOMMAX(

      1, (int)(oxcf->rc_cfg.target_bandwidth / oxcf->input_cfg.init_framerate));

}

void av1_rc_init(const AV1EncoderConfig *oxcf, RATE_CONTROL *rc) {

  const RateControlCfg *const rc_cfg = &oxcf->rc_cfg;

  rc->frames_since_key = 8;  // Sensible default for first frame.

  rc->frames_to_fwd_kf = oxcf->kf_cfg.fwd_kf_dist;

  rc->frames_till_gf_update_due = 0;

  rc->ni_av_qi = rc_cfg->worst_allowed_q;

  rc->ni_tot_qi = 0;

  rc->min_gf_interval = oxcf->gf_cfg.min_gf_interval;

  rc->max_gf_interval = oxcf->gf_cfg.max_gf_interval;

  if (rc->min_gf_interval == 0)

    rc->min_gf_interval = av1_rc_get_default_min_gf_interval(

        oxcf->frm_dim_cfg.width, oxcf->frm_dim_cfg.height,

        oxcf->input_cfg.init_framerate);

  if (rc->max_gf_interval == 0)

    rc->max_gf_interval = get_default_max_gf_interval(

        oxcf->input_cfg.init_framerate, rc->min_gf_interval);

  rc->avg_frame_low_motion = 0;

  rc->resize_state = ORIG;

  rc->resize_avg_qp = 0;

  rc->resize_buffer_underflow = 0;

  rc->resize_count = 0;

  rc->rtc_external_ratectrl = 0;

  rc->frame_level_fast_extra_bits = 0;

  rc->use_external_qp_one_pass = 0;

  rc->percent_blocks_inactive = 0;

  rc->force_max_q = 0;

  rc->postencode_drop = 0;

  rc->frames_since_scene_change = 0;

}

static bool check_buffer_below_thresh(AV1_COMP *cpi, int64_t buffer_level,

                                      int drop_mark) {

  SVC *svc = &cpi->svc;

  if (!cpi->ppi->use_svc || cpi->svc.number_spatial_layers == 1 ||

      cpi->svc.framedrop_mode == AOM_LAYER_DROP) {

    return (buffer_level <= drop_mark);

  } else {

    // For SVC in the AOM_FULL_SUPERFRAME_DROP): the condition on

    // buffer is checked on current and upper spatial layers.

    for (int i = svc->spatial_layer_id; i < svc->number_spatial_layers; ++i) {

      const int layer = LAYER_IDS_TO_IDX(i, svc->temporal_layer_id,

                                         svc->number_temporal_layers);

      LAYER_CONTEXT *lc = &svc->layer_context[layer];

      PRIMARY_RATE_CONTROL *lrc = &lc->p_rc;

      // Exclude check for layer whose bitrate is 0.

      if (lc->target_bandwidth > 0) {

        const int drop_thresh = cpi->oxcf.rc_cfg.drop_frames_water_mark;

        const int drop_mark_layer =

            (int)(drop_thresh * lrc->optimal_buffer_level / 100);

        if (lrc->buffer_level <= drop_mark_layer) return true;

      }

    }

    return false;

  }

}

int av1_rc_drop_frame(AV1_COMP *cpi) {

  const AV1EncoderConfig *oxcf = &cpi->oxcf;

  RATE_CONTROL *const rc = &cpi->rc;

  PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

#if CONFIG_FPMT_TEST

  const int simulate_parallel_frame =

      cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0 &&

      cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE;

  int64_t buffer_level =

      simulate_parallel_frame ? p_rc->temp_buffer_level : p_rc->buffer_level;

#else

  int64_t buffer_level = p_rc->buffer_level;

#endif

  // Never drop on key frame, or for frame whose base layer is key.

  // If drop_count_consec hits or exceeds max_consec_drop then don't drop.

  if (cpi->common.current_frame.frame_type == KEY_FRAME ||

      (cpi->ppi->use_svc &&

       cpi->svc.layer_context[cpi->svc.temporal_layer_id].is_key_frame) ||

      !oxcf->rc_cfg.drop_frames_water_mark ||

      (rc->max_consec_drop > 0 &&

       rc->drop_count_consec >= rc->max_consec_drop)) {

    return 0;

  } else {

    SVC *svc = &cpi->svc;

    // In the full_superframe framedrop mode for svc, if the previous spatial

    // layer was dropped, drop the current spatial layer.

    if (cpi->ppi->use_svc && svc->spatial_layer_id > 0 &&

        svc->drop_spatial_layer[svc->spatial_layer_id - 1] &&

        svc->framedrop_mode == AOM_FULL_SUPERFRAME_DROP)

      return 1;

    // -1 is passed here for drop_mark since we are checking if

    // buffer goes below 0 (<= -1).

    if (check_buffer_below_thresh(cpi, buffer_level, -1)) {

      // Always drop if buffer is below 0.

      rc->drop_count_consec++;

      return 1;

    } else {

      // If buffer is below drop_mark, for now just drop every other frame

      // (starting with the next frame) until it increases back over drop_mark.

      const int drop_mark = (int)(oxcf->rc_cfg.drop_frames_water_mark *

                                  p_rc->optimal_buffer_level / 100);

      const bool buffer_below_thresh =

          check_buffer_below_thresh(cpi, buffer_level, drop_mark);

      if (!buffer_below_thresh && rc->decimation_factor > 0) {

        --rc->decimation_factor;

      } else if (buffer_below_thresh && rc->decimation_factor == 0) {

        rc->decimation_factor = 1;

      }

      if (rc->decimation_factor > 0) {

        if (rc->decimation_count > 0) {

          --rc->decimation_count;

          rc->drop_count_consec++;

          return 1;

        } else {

          rc->decimation_count = rc->decimation_factor;

          return 0;

        }

      } else {

        rc->decimation_count = 0;

        return 0;

      }

    }

  }

}

static int adjust_q_cbr(const AV1_COMP *cpi, int q, int active_worst_quality,

                        int width, int height) {

  const RATE_CONTROL *const rc = &cpi->rc;

  const PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

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

  const SVC *const svc = &cpi->svc;

  const RefreshFrameInfo *const refresh_frame = &cpi->refresh_frame;

  // Flag to indicate previous frame has overshoot, and buffer level

  // for current frame is low (less than ~half of optimal). For such

  // (inter) frames, if the source_sad is non-zero, relax the max_delta_up

  // and clamp applied below.

  const bool overshoot_buffer_low =

      cpi->rc.rc_1_frame == -1 && rc->frame_source_sad > 1000 &&

      p_rc->buffer_level < (p_rc->optimal_buffer_level >> 1) &&

      rc->frames_since_key > 4;

  int max_delta_down;

  int max_delta_up = overshoot_buffer_low ? 120 : 20;

  const int change_avg_frame_bandwidth =

      abs(rc->avg_frame_bandwidth - rc->prev_avg_frame_bandwidth) >

      0.1 * (rc->avg_frame_bandwidth);

  // Set the maximum adjustment down for Q for this frame.

  if (cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&

      cpi->cyclic_refresh->apply_cyclic_refresh) {

    // For static screen type content limit the Q drop till the start of the

    // next refresh cycle.

    if (cpi->is_screen_content_type &&

        (cpi->cyclic_refresh->sb_index > cpi->cyclic_refresh->last_sb_index)) {

      max_delta_down = clamp(rc->q_1_frame / 32, 1, 8);

    } else {

      max_delta_down = clamp(rc->q_1_frame / 8, 1, 16);

    }

    if (!cpi->ppi->use_svc && cpi->is_screen_content_type) {

      // Link max_delta_up to max_delta_down and buffer status.

      if (p_rc->buffer_level > p_rc->optimal_buffer_level) {

        max_delta_up = AOMMAX(4, max_delta_down);

      } else if (!overshoot_buffer_low) {

        max_delta_up = AOMMAX(8, max_delta_down);

      }

    }

  } else {

    max_delta_down = cpi->is_screen_content_type

                         ? clamp(rc->q_1_frame / 16, 1, 8)

                         : clamp(rc->q_1_frame / 8, 1, 16);

  }

  // For screen static content with stable buffer level: relax the

  // limit on max_delta_down and apply bias qp, based on buffer fullness.

  // Only for high speeds levels for now to avoid bdrate regression.

  if (cpi->sf.rt_sf.rc_faster_convergence_static == 1 &&

      cpi->sf.rt_sf.check_scene_detection && rc->frame_source_sad == 0 &&

      rc->static_since_last_scene_change &&

      p_rc->buffer_level > (p_rc->optimal_buffer_level >> 1) &&

      cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&

      cpi->cyclic_refresh->counter_encode_maxq_scene_change > 4) {

    int qp_delta = 32;

    int qp_bias = 16;

    if (p_rc->buffer_level > p_rc->optimal_buffer_level) {

      qp_delta = 60;

      qp_bias = 32;

    }

    if (cpi->rc.rc_1_frame == 1) q = q - qp_bias;

    max_delta_down = AOMMAX(max_delta_down, qp_delta);

    max_delta_up = AOMMIN(max_delta_up, 4);

  }

  // If resolution changes or avg_frame_bandwidth significantly changed,

  // then set this flag to indicate change in target bits per macroblock.

  const int change_target_bits_mb =

      cm->prev_frame &&

      (width != cm->prev_frame->width || height != cm->prev_frame->height ||

       change_avg_frame_bandwidth);

  // Apply some control/clamp to QP under certain conditions.

  // Delay the use of the clamping for svc until after num_temporal_layers,

  // to make they have been set for each temporal layer.

  // Check for rc->q_1/2_frame > 0 in case they have not been set due to

  // dropped frames.

  if (!frame_is_intra_only(cm) && rc->frames_since_key > 1 &&

      rc->q_1_frame > 0 && rc->q_2_frame > 0 &&

      (!cpi->ppi->use_svc ||

       svc->current_superframe > (unsigned int)svc->number_temporal_layers) &&

      !change_target_bits_mb && !cpi->rc.rtc_external_ratectrl &&

      (!cpi->oxcf.rc_cfg.gf_cbr_boost_pct ||

       !(refresh_frame->alt_ref_frame || refresh_frame->golden_frame))) {

    // If in the previous two frames we have seen both overshoot and undershoot

    // clamp Q between the two.

    if (rc->rc_1_frame * rc->rc_2_frame == -1 &&

        rc->q_1_frame != rc->q_2_frame && !overshoot_buffer_low) {

      int qclamp = clamp(q, AOMMIN(rc->q_1_frame, rc->q_2_frame),

                         AOMMAX(rc->q_1_frame, rc->q_2_frame));

      // If the previous frame had overshoot and the current q needs to

      // increase above the clamped value, reduce the clamp for faster reaction

      // to overshoot.

      if (cpi->rc.rc_1_frame == -1 && q > qclamp && rc->frames_since_key > 10)

        q = (q + qclamp) >> 1;

      else

        q = qclamp;

    }

    // Adjust Q base on source content change from scene detection.

    if (cpi->sf.rt_sf.check_scene_detection && rc->prev_avg_source_sad > 0 &&

        rc->frames_since_key > 10 && rc->frame_source_sad > 0 &&

        !cpi->rc.rtc_external_ratectrl) {

      const int bit_depth = cm->seq_params->bit_depth;

      double delta =

          (double)rc->avg_source_sad / (double)rc->prev_avg_source_sad - 1.0;

      // Push Q downwards if content change is decreasing and buffer level

      // is stable (at least 1/4-optimal level), so not overshooting. Do so

      // only for high Q to avoid excess overshoot.

      // Else reduce decrease in Q from previous frame if content change is

      // increasing and buffer is below max (so not undershooting).

      if (delta < 0.0 &&

          p_rc->buffer_level > (p_rc->optimal_buffer_level >> 2) &&

          q > (rc->worst_quality >> 1)) {

        double q_adj_factor = 1.0 + 0.5 * tanh(4.0 * delta);

        double q_val = av1_convert_qindex_to_q(q, bit_depth);

        q += av1_compute_qdelta(rc, q_val, q_val * q_adj_factor, bit_depth);

      } else if (rc->q_1_frame - q > 0 && delta > 0.1 &&

                 p_rc->buffer_level < AOMMIN(p_rc->maximum_buffer_size,

                                             p_rc->optimal_buffer_level << 1)) {

        q = (3 * q + rc->q_1_frame) >> 2;

      }

    }

    // Limit the decrease in Q from previous frame.

    if (rc->q_1_frame - q > max_delta_down) q = rc->q_1_frame - max_delta_down;

    // Limit the increase in Q from previous frame.

    else if (q - rc->q_1_frame > max_delta_up)

      q = rc->q_1_frame + max_delta_up;

  }

  // Adjustment for temporal layers.

  if (svc->number_temporal_layers > 1 && svc->spatial_layer_id == 0 &&

      !change_target_bits_mb && !cpi->rc.rtc_external_ratectrl &&

      cpi->oxcf.resize_cfg.resize_mode != RESIZE_DYNAMIC) {

    if (svc->temporal_layer_id > 0) {

      // Constrain enhancement relative to the previous base TL0.

      // Get base temporal layer TL0.

      const int layer = LAYER_IDS_TO_IDX(0, 0, svc->number_temporal_layers);

      LAYER_CONTEXT *lc = &svc->layer_context[layer];

      // lc->rc.avg_frame_bandwidth and lc->p_rc.last_q correspond to the

      // last TL0 frame.

      const int last_qindex_tl0 =

          rc->frames_since_key < svc->number_temporal_layers

              ? lc->p_rc.last_q[KEY_FRAME]

              : lc->p_rc.last_q[INTER_FRAME];

      if (rc->avg_frame_bandwidth < lc->rc.avg_frame_bandwidth &&

          q < last_qindex_tl0 - 4)

        q = last_qindex_tl0 - 4;

    } else if (cpi->svc.temporal_layer_id == 0 && !frame_is_intra_only(cm) &&

               p_rc->buffer_level > (p_rc->optimal_buffer_level >> 2) &&

               rc->frame_source_sad < 100000) {

      // Push base TL0 Q down if buffer is stable and frame_source_sad

      // is below threshold.

      int delta = (svc->number_temporal_layers == 2) ? 4 : 10;

      q = q - delta;

    }

  }

  // For non-svc (single layer): if resolution has increased push q closer

  // to the active_worst to avoid excess overshoot.

  if (!cpi->ppi->use_svc && cm->prev_frame &&

      (width * height > 1.5 * cm->prev_frame->width * cm->prev_frame->height))

    q = (q + active_worst_quality) >> 1;

  // For single layer RPS: Bias Q based on distance of closest reference.

  if (cpi->ppi->rtc_ref.bias_recovery_frame) {

    const int min_dist = av1_svc_get_min_ref_dist(cpi);

    q = q - AOMMIN(min_dist, 20);

  }

  return clamp(q, cpi->rc.best_quality, cpi->rc.worst_quality);

}

static const RATE_FACTOR_LEVEL rate_factor_levels[FRAME_UPDATE_TYPES] = {

  KF_STD,        // KF_UPDATE

  INTER_NORMAL,  // LF_UPDATE

  GF_ARF_STD,    // GF_UPDATE

  GF_ARF_STD,    // ARF_UPDATE

  INTER_NORMAL,  // OVERLAY_UPDATE

  INTER_NORMAL,  // INTNL_OVERLAY_UPDATE

  GF_ARF_LOW,    // INTNL_ARF_UPDATE

};

static RATE_FACTOR_LEVEL get_rate_factor_level(const GF_GROUP *const gf_group,

                                               int gf_frame_index) {

  const FRAME_UPDATE_TYPE update_type = gf_group->update_type[gf_frame_index];

  assert(update_type < FRAME_UPDATE_TYPES);

  return rate_factor_levels[update_type];

}

/*!\brief Gets a rate vs Q correction factor

 *

 * This function returns the current value of a correction factor used to

 * dynamically adjust the relationship between Q and the expected number

 * of bits for the frame.

 *

 * \ingroup rate_control

 * \param[in]   cpi                   Top level encoder instance structure

 * \param[in]   width                 Frame width

 * \param[in]   height                Frame height

 *

 * \return Returns a correction factor for the current frame

 */

static double get_rate_correction_factor(const AV1_COMP *cpi, int width,

                                         int height) {

  const RATE_CONTROL *const rc = &cpi->rc;

  const PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

  const RefreshFrameInfo *const refresh_frame = &cpi->refresh_frame;

  double rcf;

  double rate_correction_factors_kfstd;

  double rate_correction_factors_gfarfstd;

  double rate_correction_factors_internormal;

  rate_correction_factors_kfstd =

      (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)

          ? rc->frame_level_rate_correction_factors[KF_STD]

          : p_rc->rate_correction_factors[KF_STD];

  rate_correction_factors_gfarfstd =

      (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)

          ? rc->frame_level_rate_correction_factors[GF_ARF_STD]

          : p_rc->rate_correction_factors[GF_ARF_STD];

  rate_correction_factors_internormal =

      (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)

          ? rc->frame_level_rate_correction_factors[INTER_NORMAL]

          : p_rc->rate_correction_factors[INTER_NORMAL];

  if (cpi->common.current_frame.frame_type == KEY_FRAME) {

    rcf = rate_correction_factors_kfstd;

  } else if (is_stat_consumption_stage(cpi)) {

    const RATE_FACTOR_LEVEL rf_lvl =

        get_rate_factor_level(&cpi->ppi->gf_group, cpi->gf_frame_index);

    double rate_correction_factors_rflvl =

        (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)

            ? rc->frame_level_rate_correction_factors[rf_lvl]

            : p_rc->rate_correction_factors[rf_lvl];

    rcf = rate_correction_factors_rflvl;

  } else {

    if ((refresh_frame->alt_ref_frame || refresh_frame->golden_frame) &&

        !rc->is_src_frame_alt_ref && !cpi->ppi->use_svc &&

        (cpi->oxcf.rc_cfg.mode != AOM_CBR ||

         cpi->oxcf.rc_cfg.gf_cbr_boost_pct > 20))

      rcf = rate_correction_factors_gfarfstd;

    else

      rcf = rate_correction_factors_internormal;

  }

  rcf *= resize_rate_factor(&cpi->oxcf.frm_dim_cfg, width, height);

  return fclamp(rcf, MIN_BPB_FACTOR, MAX_BPB_FACTOR);

}

/*!\brief Sets a rate vs Q correction factor

 *

 * This function updates the current value of a correction factor used to

 * dynamically adjust the relationship between Q and the expected number

 * of bits for the frame.

 *

 * \ingroup rate_control

 * \param[in]   cpi                   Top level encoder instance structure

 * \param[in]   is_encode_stage       Indicates if recode loop or post-encode

 * \param[in]   factor                New correction factor

 * \param[in]   width                 Frame width

 * \param[in]   height                Frame height

 *

 * \remark Updates the rate correction factor for the

 *         current frame type in cpi->rc.

 */

static void set_rate_correction_factor(AV1_COMP *cpi, int is_encode_stage,

                                       double factor, int width, int height) {

  RATE_CONTROL *const rc = &cpi->rc;

  PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;

  const RefreshFrameInfo *const refresh_frame = &cpi->refresh_frame;

  int update_default_rcf = 1;

  // Normalize RCF to account for the size-dependent scaling factor.

  factor /= resize_rate_factor(&cpi->oxcf.frm_dim_cfg, width, height);

  factor = fclamp(factor, MIN_BPB_FACTOR, MAX_BPB_FACTOR);

  if (cpi->common.current_frame.frame_type == KEY_FRAME) {

    p_rc->rate_correction_factors[KF_STD] = factor;

  } else if (is_stat_consumption_stage(cpi)) {

    const RATE_FACTOR_LEVEL rf_lvl =

        get_rate_factor_level(&cpi->ppi->gf_group, cpi->gf_frame_index);

    if (is_encode_stage &&

        cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0) {

      rc->frame_level_rate_correction_factors[rf_lvl] = factor;

      update_default_rcf = 0;

    }

    if (update_default_rcf) p_rc->rate_correction_factors[rf_lvl] = factor;

  } else {

    if ((refresh_frame->alt_ref_frame || refresh_frame->golden_frame) &&

        !rc->is_src_frame_alt_ref && !cpi->ppi->use_svc &&

        (cpi->oxcf.rc_cfg.mode != AOM_CBR ||

         cpi->oxcf.rc_cfg.gf_cbr_boost_pct > 20)) {

      p_rc->rate_correction_factors[GF_ARF_STD] = factor;

    } else {

      if (is_encode_stage &&

          cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0) {

        rc->frame_level_rate_correction_factors[INTER_NORMAL] = factor;

        update_default_rcf = 0;

      }

      if (update_default_rcf)

        p_rc->rate_correction_factors[INTER_NORMAL] = factor;

    }

  }

}

void av1_rc_update_rate_correction_factors(AV1_COMP *cpi, int is_encode_stage,

                                           int width, int height) {

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

  double correction_factor = 1.0;

  double rate_correction_factor =

      get_rate_correction_factor(cpi, width, height);

  double adjustment_limit;

  int projected_size_based_on_q = 0;

  int cyclic_refresh_active =

      cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ && cpi->common.seg.enabled;

  // Do not update the rate factors for arf overlay frames.

  if (cpi->rc.is_src_frame_alt_ref) return;

  // Don't update rate correction factors here on scene changes as

  // it is already reset in av1_encodedframe_overshoot_cbr(),

  // but reset variables related to previous frame q and size.

  // Note that the counter of frames since the last scene change

  // is only valid when cyclic refresh mode is enabled and that

  // this break out only applies to scene changes that are not

  // recorded as INTRA only key frames.

  // Note that av1_encodedframe_overshoot_cbr() is only entered

  // if cpi->sf.rt_sf.overshoot_detection_cbr == FAST_DETECTION_MAXQ

  // and cpi->rc.high_source_sad = 1.

  if ((cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ) &&

      (cpi->sf.rt_sf.overshoot_detection_cbr == FAST_DETECTION_MAXQ) &&

      cpi->rc.high_source_sad &&

      (cpi->cyclic_refresh->counter_encode_maxq_scene_change == 0) &&

      !frame_is_intra_only(cm) && !cpi->ppi->use_svc) {

    cpi->rc.q_2_frame = cm->quant_params.base_qindex;

    cpi->rc.q_1_frame = cm->quant_params.base_qindex;

    cpi->rc.rc_2_frame = 0;

    cpi->rc.rc_1_frame = 0;

    return;

  }

  // Clear down mmx registers to allow floating point in what follows

  // Work out how big we would have expected the frame to be at this Q given

  // the current correction factor.

  // Stay in double to avoid int overflow when values are large

  if (cyclic_refresh_active) {

    projected_size_based_on_q =

        av1_cyclic_refresh_estimate_bits_at_q(cpi, rate_correction_factor);

  } else {

    projected_size_based_on_q = av1_estimate_bits_at_q(

        cpi, cm->quant_params.base_qindex, rate_correction_factor);

  }

  // Work out a size correction factor.

  if (projected_size_based_on_q > FRAME_OVERHEAD_BITS)

    correction_factor = (double)cpi->rc.projected_frame_size /

                        (double)projected_size_based_on_q;

  // Clamp correction factor to prevent anything too extreme

  correction_factor = AOMMAX(correction_factor, 0.25);

  cpi->rc.q_2_frame = cpi->rc.q_1_frame;

  cpi->rc.q_1_frame = cm->quant_params.base_qindex;

  cpi->rc.rc_2_frame = cpi->rc.rc_1_frame;

  if (correction_factor > 1.1)

    cpi->rc.rc_1_frame = -1;

  else if (correction_factor < 0.9)

    cpi->rc.rc_1_frame = 1;

  else

    cpi->rc.rc_1_frame = 0;

  // Decide how heavily to dampen the adjustment

  if (correction_factor > 0.0) {

    if (cpi->is_screen_content_type) {

      adjustment_limit =

          0.25 + 0.5 * AOMMIN(0.5, fabs(log10(correction_factor)));

    } else {

      adjustment_limit =

          0.25 + 0.75 * AOMMIN(0.5, fabs(log10(correction_factor)));

    }

  } else {

    adjustment_limit = 0.75;