speed_features.h

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/*
 * 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.
 */

#ifndef AOM_AV1_ENCODER_SPEED_FEATURES_H_
#define AOM_AV1_ENCODER_SPEED_FEATURES_H_

#include "av1/common/enums.h"
#include "av1/encoder/enc_enums.h"
#include "av1/encoder/mcomp.h"
#include "av1/encoder/encodemb.h"

#ifdef __cplusplus
extern "C" {
#endif

#define MAX_MESH_STEP 4

typedef struct MESH_PATTERN {
  int range;
  int interval;
} MESH_PATTERN;

enum {
  GM_FULL_SEARCH,
  GM_REDUCED_REF_SEARCH_SKIP_L2_L3,
  GM_REDUCED_REF_SEARCH_SKIP_L2_L3_ARF2,

  // Same as GM_REDUCED_REF_SEARCH_SKIP_L2_L3_ARF2 but with extra filtering
  // to keep at most two ref frames
  GM_SEARCH_CLOSEST_REFS_ONLY,

  GM_DISABLE_SEARCH
} UENUM1BYTE(GM_SEARCH_TYPE);

enum {
  DIST_WTD_COMP_ENABLED,
  DIST_WTD_COMP_SKIP_MV_SEARCH,
  DIST_WTD_COMP_DISABLED,
} UENUM1BYTE(DIST_WTD_COMP_FLAG);

enum {
  INTRA_ALL = (1 << DC_PRED) | (1 << V_PRED) | (1 << H_PRED) | (1 << D45_PRED) |
              (1 << D135_PRED) | (1 << D113_PRED) | (1 << D157_PRED) |
              (1 << D203_PRED) | (1 << D67_PRED) | (1 << SMOOTH_PRED) |
              (1 << SMOOTH_V_PRED) | (1 << SMOOTH_H_PRED) | (1 << PAETH_PRED),
  UV_INTRA_ALL =
      (1 << UV_DC_PRED) | (1 << UV_V_PRED) | (1 << UV_H_PRED) |
      (1 << UV_D45_PRED) | (1 << UV_D135_PRED) | (1 << UV_D113_PRED) |
      (1 << UV_D157_PRED) | (1 << UV_D203_PRED) | (1 << UV_D67_PRED) |
      (1 << UV_SMOOTH_PRED) | (1 << UV_SMOOTH_V_PRED) |
      (1 << UV_SMOOTH_H_PRED) | (1 << UV_PAETH_PRED) | (1 << UV_CFL_PRED),
  UV_INTRA_DC = (1 << UV_DC_PRED),
  UV_INTRA_DC_CFL = (1 << UV_DC_PRED) | (1 << UV_CFL_PRED),
  UV_INTRA_DC_TM = (1 << UV_DC_PRED) | (1 << UV_PAETH_PRED),
  UV_INTRA_DC_PAETH_CFL =
      (1 << UV_DC_PRED) | (1 << UV_PAETH_PRED) | (1 << UV_CFL_PRED),
  UV_INTRA_DC_H_V = (1 << UV_DC_PRED) | (1 << UV_V_PRED) | (1 << UV_H_PRED),
  UV_INTRA_DC_H_V_CFL = (1 << UV_DC_PRED) | (1 << UV_V_PRED) |
                        (1 << UV_H_PRED) | (1 << UV_CFL_PRED),
  UV_INTRA_DC_PAETH_H_V = (1 << UV_DC_PRED) | (1 << UV_PAETH_PRED) |
                          (1 << UV_V_PRED) | (1 << UV_H_PRED),
  UV_INTRA_DC_PAETH_H_V_CFL = (1 << UV_DC_PRED) | (1 << UV_PAETH_PRED) |
                              (1 << UV_V_PRED) | (1 << UV_H_PRED) |
                              (1 << UV_CFL_PRED),
  INTRA_DC = (1 << DC_PRED),
  INTRA_DC_TM = (1 << DC_PRED) | (1 << PAETH_PRED),
  INTRA_DC_H_V = (1 << DC_PRED) | (1 << V_PRED) | (1 << H_PRED),
  INTRA_DC_H_V_SMOOTH =
      (1 << DC_PRED) | (1 << V_PRED) | (1 << H_PRED) | (1 << SMOOTH_PRED),
  INTRA_DC_PAETH_H_V =
      (1 << DC_PRED) | (1 << PAETH_PRED) | (1 << V_PRED) | (1 << H_PRED)
};

enum {
  INTER_ALL = (1 << NEARESTMV) | (1 << NEARMV) | (1 << GLOBALMV) |
              (1 << NEWMV) | (1 << NEAREST_NEARESTMV) | (1 << NEAR_NEARMV) |
              (1 << NEW_NEWMV) | (1 << NEAREST_NEWMV) | (1 << NEAR_NEWMV) |
              (1 << NEW_NEARMV) | (1 << NEW_NEARESTMV) | (1 << GLOBAL_GLOBALMV),
  INTER_NEAREST_NEAR_ZERO = (1 << NEARESTMV) | (1 << NEARMV) | (1 << GLOBALMV) |
                            (1 << NEAREST_NEARESTMV) | (1 << GLOBAL_GLOBALMV) |
                            (1 << NEAREST_NEWMV) | (1 << NEW_NEARESTMV) |
                            (1 << NEW_NEARMV) | (1 << NEAR_NEWMV) |
                            (1 << NEAR_NEARMV),
  INTER_SINGLE_ALL =
      (1 << NEARESTMV) | (1 << NEARMV) | (1 << GLOBALMV) | (1 << NEWMV),
};

enum {
  DISABLE_ALL_INTER_SPLIT = (1 << THR_COMP_GA) | (1 << THR_COMP_LA) |
                            (1 << THR_ALTR) | (1 << THR_GOLD) | (1 << THR_LAST),

  DISABLE_ALL_SPLIT = (1 << THR_INTRA) | DISABLE_ALL_INTER_SPLIT,

  DISABLE_COMPOUND_SPLIT = (1 << THR_COMP_GA) | (1 << THR_COMP_LA),

  LAST_AND_INTRA_SPLIT_ONLY = (1 << THR_COMP_GA) | (1 << THR_COMP_LA) |
                              (1 << THR_ALTR) | (1 << THR_GOLD)
};

enum {
  TXFM_CODING_SF = 1,
  INTER_PRED_SF = 2,
  INTRA_PRED_SF = 4,
  PARTITION_SF = 8,
  LOOP_FILTER_SF = 16,
  RD_SKIP_SF = 32,
  RESERVE_2_SF = 64,
  RESERVE_3_SF = 128,
} UENUM1BYTE(DEV_SPEED_FEATURES);

/* This enumeration defines when the rate control recode loop will be
 * enabled.
 */
enum {
  /*
   * No recodes allowed
   */
  DISALLOW_RECODE = 0,
  /*
   * Allow recode only for KF/ARF/GF frames
   */
  ALLOW_RECODE_KFARFGF = 1,
  /*
   * Allow recode for all frame types based on bitrate constraints.
   */
  ALLOW_RECODE = 2,
} UENUM1BYTE(RECODE_LOOP_TYPE);

enum {
  SUBPEL_TREE = 0,
  SUBPEL_TREE_PRUNED = 1,       // Prunes 1/2-pel searches
  SUBPEL_TREE_PRUNED_MORE = 2,  // Prunes 1/2-pel searches more aggressively
  SUBPEL_SEARCH_METHODS
} UENUM1BYTE(SUBPEL_SEARCH_METHOD);

enum {
  // Try the full image with different values.
  LPF_PICK_FROM_FULL_IMAGE,
  // Try the full image filter search with non-dual filter only.
  LPF_PICK_FROM_FULL_IMAGE_NON_DUAL,
  // Try a small portion of the image with different values.
  LPF_PICK_FROM_SUBIMAGE,
  // Estimate the level based on quantizer and frame type
  LPF_PICK_FROM_Q,
  // Pick 0 to disable LPF if LPF was enabled last frame
  LPF_PICK_MINIMAL_LPF
} UENUM1BYTE(LPF_PICK_METHOD);
typedef enum {
  CDEF_FULL_SEARCH,      
  CDEF_FAST_SEARCH_LVL1, 
  CDEF_FAST_SEARCH_LVL2, 
  CDEF_FAST_SEARCH_LVL3, 
  CDEF_FAST_SEARCH_LVL4, 
  CDEF_FAST_SEARCH_LVL5, 
  CDEF_PICK_FROM_Q,      
  CDEF_PICK_METHODS
} CDEF_PICK_METHOD;

enum {
  // Terminate search early based on distortion so far compared to
  // qp step, distortion in the neighborhood of the frame, etc.
  FLAG_EARLY_TERMINATE = 1 << 0,

  // Skips comp inter modes if the best so far is an intra mode.
  FLAG_SKIP_COMP_BESTINTRA = 1 << 1,

  // Skips oblique intra modes if the best so far is an inter mode.
  FLAG_SKIP_INTRA_BESTINTER = 1 << 3,

  // Skips oblique intra modes  at angles 27, 63, 117, 153 if the best
  // intra so far is not one of the neighboring directions.
  FLAG_SKIP_INTRA_DIRMISMATCH = 1 << 4,

  // Skips intra modes other than DC_PRED if the source variance is small
  FLAG_SKIP_INTRA_LOWVAR = 1 << 5,
} UENUM1BYTE(MODE_SEARCH_SKIP_LOGIC);

enum {
  // No tx type pruning
  TX_TYPE_PRUNE_0 = 0,
  // adaptively prunes the least perspective tx types out of all 16
  // (tuned to provide negligible quality loss)
  TX_TYPE_PRUNE_1 = 1,
  // similar, but applies much more aggressive pruning to get better speed-up
  TX_TYPE_PRUNE_2 = 2,
  TX_TYPE_PRUNE_3 = 3,
  // More aggressive pruning based on tx type score and allowed tx count
  TX_TYPE_PRUNE_4 = 4,
  TX_TYPE_PRUNE_5 = 5,
} UENUM1BYTE(TX_TYPE_PRUNE_MODE);

enum {
  // No reaction to rate control on a detected slide/scene change.
  NO_DETECTION = 0,

  // Set to larger Q based only on the detected slide/scene change and
  // current/past Q.
  FAST_DETECTION_MAXQ = 1,
} UENUM1BYTE(OVERSHOOT_DETECTION_CBR);

enum {
  // Turns off multi-winner mode. So we will do txfm search on either all modes
  // if winner mode is off, or we will only on txfm search on a single winner
  // mode.
  MULTI_WINNER_MODE_OFF = 0,

  // Limits the number of winner modes to at most 2
  MULTI_WINNER_MODE_FAST = 1,

  // Uses the default number of winner modes, which is 3 for intra mode, and 1
  // for inter mode.
  MULTI_WINNER_MODE_DEFAULT = 2,

  // Maximum number of winner modes allowed.
  MULTI_WINNER_MODE_LEVELS,
} UENUM1BYTE(MULTI_WINNER_MODE_TYPE);

enum {
  PRUNE_NEARMV_OFF = 0,     // Turn off nearmv pruning
  PRUNE_NEARMV_LEVEL1 = 1,  // Prune nearmv for qindex (0-85)
  PRUNE_NEARMV_LEVEL2 = 2,  // Prune nearmv for qindex (0-170)
  PRUNE_NEARMV_LEVEL3 = 3,  // Prune nearmv more aggressively for qindex (0-170)
  PRUNE_NEARMV_MAX = PRUNE_NEARMV_LEVEL3,
} UENUM1BYTE(PRUNE_NEARMV_LEVEL);

enum {
  // Default transform search used in evaluation of best inter candidates
  // (MODE_EVAL stage) and motion mode winner processing (WINNER_MODE_EVAL
  // stage).
  TX_SEARCH_DEFAULT = 0,
  // Transform search in motion mode rd during MODE_EVAL stage.
  TX_SEARCH_MOTION_MODE,
  // Transform search in compound type mode rd during MODE_EVAL stage.
  TX_SEARCH_COMP_TYPE_MODE,
  // All transform search cases
  TX_SEARCH_CASES
} UENUM1BYTE(TX_SEARCH_CASE);

typedef struct {
  TX_TYPE_PRUNE_MODE prune_2d_txfm_mode;

  // Limit the intra transform search type.
  // 1 : Limit the intra transform search type to the ones in the table
  // av1_derived_intra_tx_used_flag[INTRA_MODES].
  // 2 : Limit the intra transform search type to the default transform.
  int fast_intra_tx_type_search;

  // INT_MAX: Disable fast search.
  // 1 - 1024: Probability threshold used for conditionally forcing tx type,
  // during mode search.
  // 0: Force tx type to be DCT_DCT unconditionally, during
  // mode search.
  int fast_inter_tx_type_prob_thresh;

  // Prune less likely chosen transforms for each intra mode. The speed
  // feature ranges from 0 to 2, for different speed / compression trade offs.
  int use_reduced_intra_txset;

  // Use a skip flag prediction model to detect blocks with skip = 1 early
  // and avoid doing full TX type search for such blocks.
  int use_skip_flag_prediction;

  // Threshold used by the ML based method to predict TX block split decisions.
  int ml_tx_split_thresh;

  // skip remaining transform type search when we found the rdcost of skip is
  // better than applying transform
  int skip_tx_search;

  // Prune tx type search using previous frame stats.
  int prune_tx_type_using_stats;
  // Prune tx type search using estimated RDcost
  int prune_tx_type_est_rd;

  // Flag used to control the winner mode processing for tx type pruning for
  // inter blocks. It enables further tx type mode pruning based on ML model for
  // mode evaluation and disables tx type mode pruning for winner mode
  // processing.
  int winner_mode_tx_type_pruning;
} TX_TYPE_SEARCH;

enum {
  // Search partitions using RD criterion
  SEARCH_PARTITION,

  // Always use a fixed size partition
  FIXED_PARTITION,

  // Partition using source variance
  VAR_BASED_PARTITION,

#if CONFIG_RT_ML_PARTITIONING
  // Partition using ML model
  ML_BASED_PARTITION
#endif
} UENUM1BYTE(PARTITION_SEARCH_TYPE);

enum {
  NOT_IN_USE,
  DIRECT_PRED,
  RELAXED_PRED,
  ADAPT_PRED
} UENUM1BYTE(MAX_PART_PRED_MODE);

enum {
  LAST_MV_DATA,
  CURRENT_Q,
  QTR_ONLY,
} UENUM1BYTE(MV_PREC_LOGIC);

enum {
  SUPERRES_AUTO_ALL,   // Tries all possible superres ratios
  SUPERRES_AUTO_DUAL,  // Tries no superres and q-based superres ratios
  SUPERRES_AUTO_SOLO,  // Only apply the q-based superres ratio
} UENUM1BYTE(SUPERRES_AUTO_SEARCH_TYPE);
typedef enum {
  INTERNAL_COST_UPD_OFF,       
  INTERNAL_COST_UPD_TILE,      
  INTERNAL_COST_UPD_SBROW_SET, 
  INTERNAL_COST_UPD_SBROW,     
  INTERNAL_COST_UPD_SB,        
} INTERNAL_COST_UPDATE_TYPE;

typedef enum {
  NO_PRUNING = -1,
  SIMPLE_AGG_LVL0,     
  SIMPLE_AGG_LVL1,     
  SIMPLE_AGG_LVL2,     
  SIMPLE_AGG_LVL3,     
  SIMPLE_AGG_LVL4,     
  SIMPLE_AGG_LVL5,     
  QIDX_BASED_AGG_LVL1, 
  TOTAL_SIMPLE_AGG_LVLS = QIDX_BASED_AGG_LVL1, 
  TOTAL_QINDEX_BASED_AGG_LVLS =
      QIDX_BASED_AGG_LVL1 -
      SIMPLE_AGG_LVL5, 
  TOTAL_AGG_LVLS = TOTAL_SIMPLE_AGG_LVLS +
                   TOTAL_QINDEX_BASED_AGG_LVLS, 
} SIMPLE_MOTION_SEARCH_PRUNE_LEVEL;

typedef enum {
  PRUNE_MESH_SEARCH_DISABLED = 0, 
  PRUNE_MESH_SEARCH_LVL_1 = 1,    
  PRUNE_MESH_SEARCH_LVL_2 = 2,    
} PRUNE_MESH_SEARCH_LEVEL;

typedef enum {
  EARLY_TERM_DISABLED =
      0, 
  EARLY_TERM_IDX_1 =
      1, 
  EARLY_TERM_IDX_2 =
      2, 
  EARLY_TERM_IDX_3 =
      3, 
  EARLY_TERM_IDX_4 =
      4, 
  EARLY_TERM_INDICES, 
} INTER_SEARCH_EARLY_TERM_IDX;

typedef struct HIGH_LEVEL_SPEED_FEATURES {
  int frame_parameter_update;

  RECODE_LOOP_TYPE recode_loop;

  int recode_tolerance;

  MV_PREC_LOGIC high_precision_mv_usage;

  int static_segmentation;

  SUPERRES_AUTO_SEARCH_TYPE superres_auto_search_type;

  int disable_extra_sc_testing;

  int second_alt_ref_filtering;

  int adjust_num_frames_for_arf_filtering;

  int accurate_bit_estimate;

  int weight_calc_level_in_tf;

  int allow_sub_blk_me_in_tf;

  int ref_frame_mvs_lvl;

  int screen_detection_mode2_fast_detection;
} HIGH_LEVEL_SPEED_FEATURES;

typedef struct FIRST_PASS_SPEED_FEATURES {
  int reduce_mv_step_param;

  int skip_motion_search_threshold;

  int disable_recon;

  int skip_zeromv_motion_search;
} FIRST_PASS_SPEED_FEATURES;

typedef struct TPL_SPEED_FEATURES {
  // GOP length adaptive decision.
  // If set to 0, tpl model decides whether a shorter gf interval is better.
  // If set to 1, tpl stats of ARFs from base layer, (base+1) layer and
  // (base+2) layer decide whether a shorter gf interval is better.
  // If set to 2, tpl stats of ARFs from base layer, (base+1) layer and GF boost
  // decide whether a shorter gf interval is better.
  // If set to 3, gop length adaptive decision is disabled.
  int gop_length_decision_method;
  // Prune the intra modes search by tpl.
  // If set to 0, we will search all intra modes from DC_PRED to PAETH_PRED.
  // If set to 1, we only search DC_PRED, V_PRED, and H_PRED.
  int prune_intra_modes;
  // This parameter controls which step in the n-step process we start at.
  int reduce_first_step_size;
  // Skip motion estimation based on the precision of center MVs and the
  // difference between center MVs.
  // If set to 0, motion estimation is skipped for duplicate center MVs
  // (default). If set to 1, motion estimation is skipped for duplicate
  // full-pixel center MVs. If set to 2, motion estimation is skipped if the
  // difference between center MVs is less than the threshold.
  int skip_alike_starting_mv;

  // When to stop subpel search.
  SUBPEL_FORCE_STOP subpel_force_stop;

  // Which search method to use.
  SEARCH_METHODS search_method;

  // Prune starting mvs in TPL based on sad scores.
  int prune_starting_mv;

  // Prune reference frames in TPL.
  int prune_ref_frames_in_tpl;

  // Support compound predictions.
  int allow_compound_pred;

  // Calculate rate and distortion based on Y plane only.
  int use_y_only_rate_distortion;

  // Use SAD instead of SATD during intra/inter mode search.
  // If set to 0, use SATD always.
  // If set to 1, use SAD during intra/inter mode search for frames in the
  // higher temporal layers of the hierarchical prediction structure.
  // If set to 2, use SAD during intra/inter mode search for all frames.
  // This sf is disabled for the first GF group of the key-frame interval,
  // i.e., SATD is used during intra/inter mode search of the first GF group.
  int use_sad_for_mode_decision;

  // Skip tpl processing for frames of type LF_UPDATE.
  // This sf is disabled for the first GF group of the key-frame interval.
  int reduce_num_frames;
} TPL_SPEED_FEATURES;

typedef struct GLOBAL_MOTION_SPEED_FEATURES {
  GM_SEARCH_TYPE gm_search_type;

  // During global motion estimation, prune remaining reference frames in a
  // given direction(past/future), if the evaluated ref_frame in that direction
  // yields gm_type as INVALID/TRANSLATION/IDENTITY
  int prune_ref_frame_for_gm_search;

  // When the current GM type is set to ZEROMV, prune ZEROMV if its performance
  // is worse than NEWMV under SSE metric.
  // 0 : no pruning
  // 1 : conservative pruning
  // 2 : aggressive pruning
  int prune_zero_mv_with_sse;

  // Disable global motion estimation based on stats of previous frames in the
  // GF group
  int disable_gm_search_based_on_stats;

  // Downsampling pyramid level to use for global motion estimation
  int downsample_level;

  // Number of refinement steps to apply after initial model generation
  int num_refinement_steps;

  // Error advantage threshold level used to determine whether global motion
  // compensation should be enabled
  int gm_erroradv_tr_level;
} GLOBAL_MOTION_SPEED_FEATURES;

typedef struct PARTITION_SPEED_FEATURES {
  PARTITION_SEARCH_TYPE partition_search_type;

  // Used if partition_search_type = FIXED_PARTITION
  BLOCK_SIZE fixed_partition_size;

  // Prune extended partition types search based on the current best partition
  // and the combined rdcost of the subblocks estimated from previous
  // partitions. Can take values 0 - 2, 0 referring to no pruning, and 1 - 2
  // increasing aggressiveness of pruning in order.
  int prune_ext_partition_types_search_level;

  // Prune part4 based on block size
  int prune_part4_search;

  // Use a ML model to prune rectangular, ab and 4-way horz
  // and vert partitions
  int ml_prune_partition;

  // Use a ML model to adaptively terminate partition search after trying
  // PARTITION_SPLIT. Can take values 0 - 2, 0 meaning not being enabled, and
  // 1 - 2 increasing aggressiveness in order.
  int ml_early_term_after_part_split_level;

  // Skip rectangular partition test when partition type none gives better
  // rd than partition type split. Can take values 0 - 2, 0 referring to no
  // skipping, and 1 - 2 increasing aggressiveness of skipping in order.
  int less_rectangular_check_level;

  // Use square partition only beyond this block size.
  BLOCK_SIZE use_square_partition_only_threshold;

  // Sets max square partition levels for this superblock based on
  // motion vector and prediction error distribution produced from 16x16
  // simple motion search
  MAX_PART_PRED_MODE auto_max_partition_based_on_simple_motion;

  // Min and max square partition size we enable (block_size) as per auto
  // min max, but also used by adjust partitioning, and pick_partitioning.
  BLOCK_SIZE default_min_partition_size;
  BLOCK_SIZE default_max_partition_size;

  // Sets level of adjustment of variance-based partitioning during
  // rd_use_partition 0 - no partition adjustment, 1 - try to merge partitions
  // for small blocks and high QP, 2 - try to merge partitions, 3 - try to merge
  // and split leaf partitions and 0 - 3 decreasing aggressiveness in order.
  int adjust_var_based_rd_partitioning;

  // Partition search early breakout thresholds.
  int64_t partition_search_breakout_dist_thr;
  int partition_search_breakout_rate_thr;

  // Thresholds for ML based partition search breakout.
  float ml_partition_search_breakout_thresh[PARTITION_BLOCK_SIZES];

  // ML based partition search breakout model index
  int ml_partition_search_breakout_model_index;

  // ML based partition search breakout model index
  int ml_4_partition_search_level_index;

  // Aggressiveness levels for pruning split and rectangular partitions based on
  // simple_motion_search. SIMPLE_AGG_LVL0 to SIMPLE_AGG_LVL5 correspond to
  // simple motion search based pruning. QIDX_BASED_AGG_LVL1 corresponds to
  // qindex based and simple motion search based pruning.
  int simple_motion_search_prune_agg;

  // Perform simple_motion_search on each possible subblock and use it to prune
  // PARTITION_HORZ and PARTITION_VERT.
  int simple_motion_search_prune_rect;

  // Perform simple motion search before none_partition to decide if we
  // want to remove all partitions other than PARTITION_SPLIT. If set to 0, this
  // model is disabled. If set to 1, the model attempts to perform
  // PARTITION_SPLIT only. If set to 2, the model also attempts to prune
  // PARTITION_SPLIT.
  int simple_motion_search_split;

  // Use features from simple_motion_search to terminate prediction block
  // partition after PARTITION_NONE
  int simple_motion_search_early_term_none;

  // Controls whether to reduce the number of motion search steps. If this is 0,
  // then simple_motion_search has the same number of steps as
  // single_motion_search (assuming no other speed features). Otherwise, reduce
  // the number of steps by the value contained in this variable.
  int simple_motion_search_reduce_search_steps;

  // This variable controls the maximum block size where intra blocks can be
  // used in inter frames.
  // TODO(aconverse): Fold this into one of the other many mode skips
  BLOCK_SIZE max_intra_bsize;

  // Use CNN with luma pixels on source frame on each of the 64x64 subblock to
  // perform partition pruning in intra frames.
  // 0: No Pruning
  // 1: Prune split and rectangular partitions only
  // 2: Prune none, split and rectangular partitions
  int intra_cnn_based_part_prune_level;

  // Disable extended partition search if the current bsize is greater than the
  // threshold. Must be a square block size BLOCK_8X8 or higher.
  BLOCK_SIZE ext_partition_eval_thresh;

  // Use best partition decision so far to tune 'ext_partition_eval_thresh'
  int ext_part_eval_based_on_cur_best;

  // Disable rectangular partitions for larger block sizes.
  int rect_partition_eval_thresh;

  // Prune extended partition search based on whether the split/rect partitions
  // provided an improvement in the previous search.
  // 0 : no pruning
  // 1 : prune 1:4 partition search using winner info from split partitions
  // 2 : prune 1:4 and AB partition search using split and HORZ/VERT info
  int prune_ext_part_using_split_info;

  // Prunt rectangular, AB and 4-way partition based on q index and block size
  // 0 : no pruning
  // 1 : prune sub_8x8 at very low quantizers
  // 2 : prune all block size based on qindex
  int prune_rectangular_split_based_on_qidx;

  // Prune rectangular partitions based on 4x4 sub-block variance
  // false : no pruning
  // true : prune rectangular partitions based on 4x4 sub-block variance
  // deviation
  //
  // For allintra encode, this speed feature reduces instruction count by 6.4%
  // for speed=6 with coding performance change less than 0.24%. For AVIF image
  // encode, this speed feature reduces encode time by 8.14% for speed 6 on a
  // typical image dataset with coding performance change less than 0.16%. This
  // speed feature is not applicable to speed >= 7.
  bool prune_rect_part_using_4x4_var_deviation;

  // Prune rectangular partitions based on prediction mode chosen by NONE
  // partition.
  // false : no pruning
  // true : prunes rectangular partition as described below
  // If prediction mode chosen by NONE partition is
  // DC_PRED or SMOOTH_PRED: Prunes both horizontal and vertical partitions if
  // at least one of the left and top neighbor blocks is larger than the
  // current block.
  // Directional Mode: Prunes either of the horizontal and vertical partition
  // based on center angle of the prediction mode chosen by NONE partition. For
  // example, vertical partition is pruned if center angle of the prediction
  // mode chosen by NONE partition is close to 180 degrees (i.e. horizontal
  // direction) and vice versa.
  // For allintra encode, this speed feature reduces instruction count by 5.1%
  // for speed=6 with coding performance change less than 0.22%. For AVIF image
  // encode, this speed feature reduces encode time by 4.44% for speed 6 on a
  // typical image dataset with coding performance change less than 0.15%.
  // For speed >= 7, variance-based logic is used to determine the partition
  // structure instead of recursive partition search. Therefore, this speed
  // feature is not applicable in such cases.
  bool prune_rect_part_using_none_pred_mode;

  // Terminate partition search for child partition,
  // when NONE and SPLIT partition rd_costs are INT64_MAX.
  int early_term_after_none_split;

  // Level used to adjust threshold for av1_ml_predict_breakout(). At lower
  // levels, more conservative threshold is used, and value of 0 indicates
  // av1_ml_predict_breakout() is disabled. Value of 3 corresponds to default
  // case with no adjustment to lbd thresholds.
  int ml_predict_breakout_level;

  // Prune sub_8x8 (BLOCK_4X4, BLOCK_4X8 and BLOCK_8X4) partitions.
  // 0 : no pruning
  // 1 : pruning based on neighbour block information
  // 2 : prune always
  int prune_sub_8x8_partition_level;

  // Prune rectangular split based on simple motion search split/no_split score.
  // 0: disable pruning, 1: enable pruning
  int simple_motion_search_rect_split;

  // The current encoder adopts a DFS search for block partitions.
  // Therefore the mode selection and associated rdcost is ready for smaller
  // blocks before the mode selection for some partition types.
  // AB partition could use previous rd information and skip mode search.
  // An example is:
  //
  //  current block
  //  +---+---+
  //  |       |
  //  +       +
  //  |       |
  //  +-------+
  //
  //  SPLIT partition has been searched first before trying HORZ_A
  //  +---+---+
  //  | R | R |
  //  +---+---+
  //  | R | R |
  //  +---+---+
  //
  //  HORZ_A
  //  +---+---+
  //  |   |   |
  //  +---+---+
  //  |       |
  //  +-------+
  //
  //  With this speed feature, the top two sub blocks can directly use rdcost
  //  searched in split partition, and the mode info is also copied from
  //  saved info. Similarly, the bottom rectangular block can also use
  //  the available information from previous rectangular search.
  int reuse_prev_rd_results_for_part_ab;

  // Reuse the best prediction modes found in PARTITION_SPLIT and PARTITION_RECT
  // when encoding PARTITION_AB.
  int reuse_best_prediction_for_part_ab;

  // The current partition search records the best rdcost so far and uses it
  // in mode search and transform search to early skip when some criteria is
  // met. For example, when the current rdcost is larger than the best rdcost,
  // or the model rdcost is larger than the best rdcost times some thresholds.
  // By default, this feature is turned on to speed up the encoder partition
  // search.
  // If disabling it, at speed 0, 30 frames, we could get
  // about -0.25% quality gain (psnr, ssim, vmaf), with about 13% slowdown.
  int use_best_rd_for_pruning;

  // Skip evaluation of non-square partitions based on the corresponding NONE
  // partition.
  // 0: no pruning
  // 1: prune extended partitions if NONE is skippable
  // 2: on top of 1, prune rectangular partitions if NONE is inter, not a newmv
  // mode and skippable
  int skip_non_sq_part_based_on_none;

  // Disables 8x8 and below partitions for low quantizers.
  int disable_8x8_part_based_on_qidx;

  // Disables either of PARTITION_HORZ_4 or PARTITION_VERT_4 using SSE from
  // simple motion search.
  bool prune_h_or_v_4part_using_sms_info;

  // Decoder side speed feature to add penalty for use of smaller partitions.
  // Takes values 0 - 2, 0 indicating no penalty and higher level indicating
  // increased penalty.
  int split_partition_penalty_level;
} PARTITION_SPEED_FEATURES;

typedef struct MV_SPEED_FEATURES {
  // Motion search method (Diamond, NSTEP, Hex, Big Diamond, Square, etc).
  SEARCH_METHODS search_method;

  // Enable the use of faster, less accurate mv search method
  // 0: Disable
  // 1 - 3: Disable for larger bsize
  // 4: Based on bsize, SAD and qp
  // TODO(chiyotsai@google.com): Take the clip's resolution and mv activity into
  // account.
  int use_bsize_dependent_search_method;

  // If this is set to 1, we limit the motion search range to 2 times the
  // largest motion vector found in the last frame.
  int auto_mv_step_size;

  // Subpel_search_method can only be subpel_tree which does a subpixel
  // logarithmic search that keeps stepping at 1/2 pixel units until
  // you stop getting a gain, and then goes on to 1/4 and repeats
  // the same process. Along the way it skips many diagonals.
  SUBPEL_SEARCH_METHOD subpel_search_method;

  // Maximum number of steps in logarithmic subpel search before giving up.
  int subpel_iters_per_step;

  // When to stop subpel search.
  SUBPEL_FORCE_STOP subpel_force_stop;

  // When to stop subpel search in simple motion search.
  SUBPEL_FORCE_STOP simple_motion_subpel_force_stop;

  // If true, sub-pixel search uses the exact convolve function used for final
  // encoding and decoding; otherwise, it uses bilinear interpolation.
  SUBPEL_SEARCH_TYPE use_accurate_subpel_search;

  // Threshold for allowing exhaustive motion search.
  int exhaustive_searches_thresh;

  // Pattern to be used for any exhaustive mesh searches (except intraBC ME).
  MESH_PATTERN mesh_patterns[MAX_MESH_STEP];

  // Pattern to be used for exhaustive mesh searches of intraBC ME.
  MESH_PATTERN intrabc_mesh_patterns[MAX_MESH_STEP];

  // Reduce single motion search range based on MV result of prior ref_mv_idx.
  int reduce_search_range;

  // Prune mesh search.
  PRUNE_MESH_SEARCH_LEVEL prune_mesh_search;

  // Use the rd cost around the best FULLPEL_MV to speed up subpel search
  int use_fullpel_costlist;

  // Set the full pixel search level of obmc
  // 0: obmc_full_pixel_diamond
  // 1: obmc_refining_search_sad (faster)
  int obmc_full_pixel_search_level;

  // Accurate full pixel motion search based on TPL stats.
  int full_pixel_search_level;

  // Allow intrabc motion search
  int use_intrabc;

  // Prune intrabc candidate block hash search
  // 0: check every block hash candidate
  // 1: check the first 64 block hash candidates only
  int prune_intrabc_candidate_block_hash_search;

  // Intrabc search level
  // 0: top + left search, all block sizes, always hash plus pixel search
  // 1: top search only, 4x4, 8x8 and 16x16 block sizes only, perform pixel
  //    search if and only if hash search failed to find a candidate
  int intrabc_search_level;

  // Whether the maximum intrabc block size to hash is 8x8
  // 0: Hash from 4x4 up to superblock size
  // 1: Hash 4x4 and 8x8 only
  int hash_max_8x8_intrabc_blocks;

  // Whether to downsample the rows in sad calculation during motion search.
  // This is only active when there are at least 16 rows. When this sf is
  // active, if there is a large discrepancy in the SAD values for the final
  // motion vector between skipping vs not skipping, motion search is redone
  // with skip row features off.
  // 0: Disabled (do not downsample rows)
  // 1: Skip SAD calculation of odd rows if the SAD deviation of the even and
  //    odd rows for the starting MV is small. Redo motion search with sf off
  //    when SAD deviation is high for the final motion vector.
  // 2: Skip SAD calculation of odd rows. SAD deviation is not tested for the
  //    start MV and tested only for the final MV.
  int use_downsampled_sad;

  // Enable/disable extensive joint motion search.
  int disable_extensive_joint_motion_search;

  // Enable second best mv check in joint mv search.
  // 0: allow second MV (use rd cost as the metric)
  // 1: use var as the metric
  // 2: disable second MV
  int disable_second_mv;

  // Skips full pixel search based on closeness of start mv and ref mv
  // of previous search.
  // 0: Disabled
  // 1: Skips the full pixel search upto 4 neighbor full-pel start MV and ref MV
  // positions.
  // 2: Skips the full pixel search upto 8 neighbor full-pel start MV and ref MV
  // positions.
  int skip_fullpel_search_using_startmv_refmv;

  // Method to use for refining WARPED_CAUSAL motion vectors
  // TODO(rachelbarker): Can this be unified with OBMC in some way?
  WARP_SEARCH_METHOD warp_search_method;

  // Maximum number of iterations in WARPED_CAUSAL refinement search
  int warp_search_iters;
} MV_SPEED_FEATURES;

typedef struct INTER_MODE_SPEED_FEATURES {
  // 2-pass inter mode model estimation where the preliminary pass skips
  // transform search and uses a model to estimate rd, while the final pass
  // computes the full transform search. Two types of models are supported:
  // 0: not used
  // 1: used with online dynamic rd model
  // 2: used with static rd model
  int inter_mode_rd_model_estimation;

  // Bypass transform search based on skip rd at following stages
  //   i. Compound type mode search
  //  ii. Motion mode search (mode evaluation and winner motion mode stage)
  // iii. Transform search for best inter candidates
  int txfm_rd_gate_level[TX_SEARCH_CASES];

  // Limit the inter mode tested in the RD loop
  int reduce_inter_modes;

  // This variable is used to cap the maximum number of times we skip testing a
  // mode to be evaluated. A high value means we will be faster.
  int adaptive_rd_thresh;

  // Aggressively prune inter modes when best mode is skippable.
  int prune_inter_modes_if_skippable;

  // Drop less likely to be picked reference frames in the RD search.
  // Has seven levels for now: 0, 1, 2, 3, 4, 5 and 6 where higher levels prune
  // more aggressively than lower ones. (0 means no pruning).
  int selective_ref_frame;

  // Prune reference frames for rectangular partitions.
  // 0 implies no pruning
  // 1 implies prune for extended partition
  // 2 implies prune horiz, vert and extended partition
  int prune_ref_frame_for_rect_partitions;

  // Prune inter modes w.r.t past reference frames
  // 0 no pruning
  // 1 prune inter modes w.r.t ALTREF2 and ALTREF reference frames
  // 2 prune inter modes w.r.t BWDREF, ALTREF2 and ALTREF reference frames
  int alt_ref_search_fp;

  // Prune reference frames for single prediction modes based on temporal
  // distance and pred MV SAD. Feasible values are 0-4. The feature is
  // disabled for 0. An increasing value indicates more aggressive pruning
  // threshold.
  int prune_single_ref;

  // Prune compound reference frames
  // 0 no pruning
  // 1 prune based on temporal distance and pred_mv_sad. However, disallow
  //   pruning of important reference frame pairs decided based on temporal
  //   distance and quality.
  // 2 prune compound references which do not satisfy the two conditions:
  //   a) The references are at a nearest distance from the current frame in
  //   both past and future direction.
  //   b) The references have minimum pred_mv_sad in both past and future
  //   direction.
  // 3 prune compound references except the one with nearest distance from the
  //   current frame in both past and future direction.
  int prune_comp_ref_frames;

  // Skip the current ref_mv in NEW_MV mode based on mv, rate cost, etc.
  // This speed feature equaling 0 means no skipping.
  // If the speed feature equals 1 or 2, skip the current ref_mv in NEW_MV mode
  // if we have already encountered ref_mv in the drl such that:
  //  1. The other drl has the same mv during the SIMPLE_TRANSLATION search
  //     process as the current mv.
  //  2. The rate needed to encode the current mv is larger than that for the
  //     other ref_mv.
  // The speed feature equaling 1 means using subpel mv in the comparison.
  // The speed feature equaling 2 means using fullpel mv in the comparison.
  // If the speed feature >= 3, skip the current ref_mv in NEW_MV mode based on
  // known full_mv bestsme and drl cost.
  int skip_newmv_in_drl;

  // This speed feature checks duplicate ref MVs among NEARESTMV, NEARMV,
  // GLOBALMV and skips NEARMV or GLOBALMV (in order) if a duplicate is found
  // TODO(any): Instead of skipping repeated ref mv, use the recalculated
  // rd-cost based on mode rate and skip the mode evaluation
  int skip_repeated_ref_mv;

  // Flag used to control the ref_best_rd based gating for chroma
  int perform_best_rd_based_gating_for_chroma;

  // Reuse the inter_intra_mode search result from NEARESTMV mode to other
  // single ref modes
  int reuse_inter_intra_mode;

  // prune wedge and compound segment approximate rd evaluation based on
  // compound average modeled rd
  int prune_comp_type_by_model_rd;

  // prune wedge and compound segment approximate rd evaluation based on
  // compound average rd/ref_best_rd
  int prune_comp_type_by_comp_avg;

  // Skip some ref frames in compound motion search by single motion search
  // result. Has three levels for now: 0 referring to no skipping, and 1 - 3
  // increasing aggressiveness of skipping in order.
  // Note: The search order might affect the result. It assumes that the single
  // reference modes are searched before compound modes. It is better to search
  // same single inter mode as a group.
  int prune_comp_search_by_single_result;

  // Instead of performing a full MV search, do a simple translation first
  // and only perform a full MV search on the motion vectors that performed
  // well.
  int prune_mode_search_simple_translation;

  // Only search compound modes with at least one "good" reference frame.
  // A reference frame is good if, after looking at its performance among
  // the single reference modes, it is one of the two best performers.
  int prune_compound_using_single_ref;

  // Skip extended compound mode (NEAREST_NEWMV, NEW_NEARESTMV, NEAR_NEWMV,
  // NEW_NEARMV) using ref frames of above and left neighbor
  // blocks.
  // 0 : no pruning
  // 1 : prune ext compound modes using neighbor blocks (less aggressiveness)
  // 2 : prune ext compound modes using neighbor blocks (high aggressiveness)
  // 3 : prune ext compound modes unconditionally (highest aggressiveness)
  int prune_ext_comp_using_neighbors;

  // Skip NEW_NEARMV and NEAR_NEWMV extended compound modes
  int skip_ext_comp_nearmv_mode;

  // Skip extended compound mode when ref frame corresponding to NEWMV does not
  // have NEWMV as single mode winner.
  // 0 : no pruning
  // 1 : prune extended compound mode (less aggressiveness)
  // 2 : prune extended compound mode (high aggressiveness)
  int prune_comp_using_best_single_mode_ref;

  // Skip NEARESTMV and NEARMV using weight computed in ref mv list population
  //
  // Pruning is enabled only when both the top and left neighbor blocks are
  // available and when the current block already has a valid inter prediction.
  int prune_nearest_near_mv_using_refmv_weight;

  // Based on previous ref_mv_idx search result, prune the following search.
  int prune_ref_mv_idx_search;

  // Disable one sided compound modes.
  int disable_onesided_comp;

  // Prune obmc search using previous frame stats.
  // INT_MAX : disable obmc search
  int prune_obmc_prob_thresh;

  // Prune warped motion search using previous frame stats.
  int prune_warped_prob_thresh;

  // Variance threshold to enable/disable Interintra wedge search
  unsigned int disable_interintra_wedge_var_thresh;

  // Variance threshold to enable/disable Interinter wedge search
  unsigned int disable_interinter_wedge_var_thresh;

  // De-couple wedge and mode search during interintra RDO.
  int fast_interintra_wedge_search;

  // Whether fast wedge sign estimate is used
  int fast_wedge_sign_estimate;

  // Enable/disable ME for interinter wedge search.
  int disable_interinter_wedge_newmv_search;

  // Decide when and how to use joint_comp.
  DIST_WTD_COMP_FLAG use_dist_wtd_comp_flag;

  // Clip the frequency of updating the mv cost.
  INTERNAL_COST_UPDATE_TYPE mv_cost_upd_level;

  // Clip the frequency of updating the coeff cost.
  INTERNAL_COST_UPDATE_TYPE coeff_cost_upd_level;

  // Clip the frequency of updating the mode cost.
  INTERNAL_COST_UPDATE_TYPE mode_cost_upd_level;

  // Prune inter modes based on tpl stats
  // 0 : no pruning
  // 1 : Allow pruning of LAST2 frame
  // 2 - 4: Allow pruning of all reference frames with increased aggressiveness
  // of pruning in order
  int prune_inter_modes_based_on_tpl;

  // Skip NEARMV and NEAR_NEARMV modes using ref frames of above and left
  // neighbor blocks and qindex.
  PRUNE_NEARMV_LEVEL prune_nearmv_using_neighbors;

  // Model based breakout after interpolation filter search
  // 0: no breakout
  // 1: use model based rd breakout
  int model_based_post_interp_filter_breakout;

  // Reuse compound type rd decision when exact match is found
  // 0: No reuse
  // 1: Reuse the compound type decision
  int reuse_compound_type_decision;

  // Enable/disable masked compound.
  int disable_masked_comp;

  // Enable/disable MV refinement for compound modes corresponds to compound
  // types COMPOUND_AVERAGE, COMPOUND_DISTWTD (currently, this compound type
  // is disabled for speeds >= 2 using the sf 'use_dist_wtd_comp_flag') and
  // COMPOUND_DIFFWTD based on the availability. Levels 0 to 3 indicate
  // increasing order of aggressiveness to disable MV refinement.
  // 0: MV Refinement is enabled and for NEW_NEWMV mode used two iterations of
  // refinement in av1_joint_motion_search().
  // 1: MV Refinement is disabled for COMPOUND_DIFFWTD and enabled for
  // COMPOUND_AVERAGE & COMPOUND_DISTWTD.
  // 2: MV Refinement is enabled for COMPOUND_AVERAGE & COMPOUND_DISTWTD for
  // NEW_NEWMV mode with one iteration of refinement in
  // av1_joint_motion_search() and MV Refinement is disabled for other compound
  // type modes.
  // 3: MV Refinement is disabled.
  int enable_fast_compound_mode_search;

  // Reuse masked compound type search results
  int reuse_mask_search_results;

  // Enable/disable fast search for wedge masks
  int enable_fast_wedge_mask_search;

  // Early breakout from transform search of inter modes
  int inter_mode_txfm_breakout;

  // Limit number of inter modes for txfm search if a newmv mode gets
  // evaluated among the top modes.
  // 0: no pruning
  // 1 to 3 indicate increasing order of aggressiveness
  int limit_inter_mode_cands;

  // Cap the no. of txfm searches for a given prediction mode.
  // 0: no cap, 1: cap beyond first 4 searches, 2: cap beyond first 3 searches.
  int limit_txfm_eval_per_mode;

  // Prune warped motion search based on block size.
  int extra_prune_warped;

  // Do not search compound modes for ARF.
  // The intuition is that ARF is predicted by frames far away from it,
  // whose temporal correlations with the ARF are likely low.
  // It is therefore likely that compound modes do not work as well for ARF
  // as other inter frames.
  // Speed/quality impact:
  // Speed 1: 12% faster, 0.1% psnr loss.
  // Speed 2: 2%  faster, 0.05% psnr loss.
  // No change for speed 3 and up, because |disable_onesided_comp| is true.
  int skip_arf_compound;

  // Percentage of scaling used to increase the rd cost of warp mode so that
  // encoder decisions are biased against local warp, favoring low complexity
  // modes.
  int bias_warp_mode_rd_scale_pct;

  // Percentage of scaling used to increase the rd cost of obmc motion mode so
  // that encoder decisions are biased against local obmc, favoring low
  // complexity modes.
  float bias_obmc_mode_rd_scale_pct;

  // Avoid further evaluation of compound modes using top estimate RD Costs of
  // compound average.
  // Values are 0 (not used),1 - 3 with progressively increasing
  // aggressiveness, i.e., decreasing number of top candidates.
  int skip_cmp_using_top_cmp_avg_est_rd_lvl;

  // Skip interinter wedge search based on MSE between the two predictors.
  int skip_interinter_wedge_search_based_on_mse;
} INTER_MODE_SPEED_FEATURES;

typedef struct INTERP_FILTER_SPEED_FEATURES {
  // Do limited interpolation filter search for dual filters, since best choice
  // usually includes EIGHTTAP_REGULAR.
  int use_fast_interpolation_filter_search;

  // Disable dual filter
  int disable_dual_filter;

  // Save results of av1_interpolation_filter_search for a block
  // Check mv and ref_frames before search, if they are very close with previous
  // saved results, filter search can be skipped.
  int use_interp_filter;

  // skip sharp_filter evaluation based on regular and smooth filter rd for
  // dual_filter=0 case
  int skip_sharp_interp_filter_search;

  // skip interpolation filter search for a block in chessboard pattern
  int cb_pred_filter_search;

  // adaptive interp_filter search to allow skip of certain filter types.
  int adaptive_interp_filter_search;

  // Forces interpolation filter to EIGHTTAP_REGULAR and skips interpolation
  // filter search.
  int skip_interp_filter_search;

  // Bias towards sharp filter
  int use_more_sharp_interp;

  // Skip model RD evaluation of chroma planes during interpolation filter
  // search.
  int skip_model_rd_uv;
} INTERP_FILTER_SPEED_FEATURES;

typedef struct INTRA_MODE_SPEED_FEATURES {
  // These bit masks allow you to enable or disable intra modes for each
  // transform size separately.
  int intra_y_mode_mask[TX_SIZES];
  int intra_uv_mode_mask[TX_SIZES];

  // flag to allow skipping intra mode for inter frame prediction
  int skip_intra_in_interframe;

  // Prune intra mode candidates based on source block histogram of gradient.
  // Applies to luma plane only.
  // Feasible values are 0..4. The feature is disabled for 0. An increasing
  // value indicates more aggressive pruning threshold.
  int intra_pruning_with_hog;

  // Prune intra mode candidates based on source block histogram of gradient.
  // Applies to chroma plane only.
  // Feasible values are 0..4. The feature is disabled for 0. An increasing
  // value indicates more aggressive pruning threshold.
  int chroma_intra_pruning_with_hog;

  // Enable/disable smooth intra modes.
  int disable_smooth_intra;

  // Prune UV_SMOOTH_PRED mode for chroma based on chroma source variance.
  // false : No pruning
  // true  : Prune UV_SMOOTH_PRED mode based on chroma source variance
  //
  // For allintra encode, this speed feature reduces instruction count
  // by 1.90%, 2.21% and 1.97% for speed 6, 7 and 8 with coding performance
  // change less than 0.04%. For AVIF image encode, this speed feature reduces
  // encode time by 1.56%, 2.14% and 0.90% for speed 6, 7 and 8 on a typical
  // image dataset with coding performance change less than 0.05%.
  bool prune_smooth_intra_mode_for_chroma;

  // Prune filter intra modes in intra frames.
  // 0 : No pruning
  // 1 : Evaluate applicable filter intra modes based on best intra mode so far
  // 2 : Do not evaluate filter intra modes
  int prune_filter_intra_level;

  // prune palette search
  // 0: No pruning
  // 1: Perform coarse search to prune the palette colors. For winner colors,
  // neighbors are also evaluated using a finer search.
  // 2: Perform 2 way palette search from max colors to min colors (and min
  // colors to remaining colors) and terminate the search if current number of
  // palette colors is not the winner.
  int prune_palette_search_level;

  // Terminate early in luma palette_size search. Speed feature values indicate
  // increasing level of pruning.
  // 0: No early termination
  // 1: Terminate early for higher luma palette_size, if header rd cost of lower
  // palette_size is more than 2 * best_rd. This level of pruning is more
  // conservative when compared to sf level 2 as the cases which will get pruned
  // with sf level 1 is a subset of the cases which will get pruned with sf
  // level 2.
  // 2: Terminate early for higher luma palette_size, if header rd cost of lower
  // palette_size is more than best_rd.
  // For allintra encode, this sf reduces instruction count by 2.49%, 1.07%,
  // 2.76%, 2.30%, 1.84%, 2.69%, 2.04%, 2.05% and 1.44% for speed 0, 1, 2, 3, 4,
  // 5, 6, 7 and 8 on screen content set with coding performance change less
  // than 0.01% for speed <= 2 and less than 0.03% for speed >= 3. For AVIF
  // image encode, this sf reduces instruction count by 1.94%, 1.13%, 1.29%,
  // 0.93%, 0.89%, 1.03%, 1.07%, 1.20% and 0.18% for speed 0, 1, 2, 3, 4, 5, 6,
  // 7 and 8 on a typical image dataset with coding performance change less than
  // 0.01%.
  int prune_luma_palette_size_search_level;

  // Prune chroma intra modes based on luma intra mode winner.
  // 0: No pruning
  // 1: Prune chroma intra modes other than UV_DC_PRED, UV_SMOOTH_PRED,
  // UV_CFL_PRED and the mode that corresponds to luma intra mode winner.
  int prune_chroma_modes_using_luma_winner;

  // Clip the frequency of updating the mv cost for intrabc.
  INTERNAL_COST_UPDATE_TYPE dv_cost_upd_level;

  // We use DCT_DCT transform followed by computing SATD (Sum of Absolute
  // Transformed Differences) as an estimation of RD score to quickly find the
  // best possible Chroma from Luma (CFL) parameter. Then we do a full RD search
  // near the best possible parameter. The search range is set here.
  // The range of cfl_searh_range should be [1, 33], and the following are the
  // recommended values.
  // 1: Fastest mode.
  // 3: Default mode that provides good speedup without losing compression
  // performance at speed 0.
  // 33: Exhaustive rd search (33 == CFL_MAGS_SIZE). This mode should only
  // be used for debugging purpose.
  int cfl_search_range;

  // TOP_INTRA_MODEL_COUNT is 4 that is the number of top model rd to store in
  // intra mode decision. Here, add a speed feature to reduce this number for
  // higher speeds.
  int top_intra_model_count_allowed;

  // Adapt top_intra_model_count_allowed locally to prune luma intra modes using
  // neighbor block and quantizer information.
  int adapt_top_model_rd_count_using_neighbors;

  // Prune the evaluation of odd delta angles of directional luma intra modes by
  // using the rdcosts of neighbouring delta angles.
  // For allintra encode, this speed feature reduces instruction count
  // by 4.461%, 3.699% and 3.536% for speed 6, 7 and 8 on a typical video
  // dataset with coding performance change less than 0.26%. For AVIF image
  // encode, this speed feature reduces encode time by 2.849%, 2.471%,
  // and 2.051% for speed 6, 7 and 8 on a typical image dataset with coding
  // performance change less than 0.27%.
  int prune_luma_odd_delta_angles_in_intra;

  // Terminate early in chroma palette_size search.
  // 0: No early termination
  // 1: Terminate early for higher palette_size, if header rd cost of lower
  // palette_size is more than best_rd.
  // For allintra encode, this sf reduces instruction count by 0.45%,
  // 0.62%, 1.73%, 2.50%, 2.89%, 3.09% and 3.86% for speed 0 to 6 on screen
  // content set with coding performance change less than 0.01%.
  // For AVIF image encode, this sf reduces instruction count by 0.45%, 0.81%,
  // 0.85%, 1.05%, 1.45%, 1.66% and 1.95% for speed 0 to 6 on a typical image
  // dataset with no quality drop.
  int early_term_chroma_palette_size_search;

  // Skips the evaluation of filter intra modes in inter frames if rd evaluation
  // of luma intra dc mode results in invalid rd stats.
  int skip_filter_intra_in_inter_frames;
} INTRA_MODE_SPEED_FEATURES;

typedef struct TX_SPEED_FEATURES {
  // Init search depth for square and rectangular transform partitions.
  // Values:
  // 0 - search full tree, 1: search 1 level, 2: search the highest level only
  int inter_tx_size_search_init_depth_sqr;
  int inter_tx_size_search_init_depth_rect;
  int intra_tx_size_search_init_depth_sqr;
  int intra_tx_size_search_init_depth_rect;

  // If any dimension of a coding block size above 64, always search the
  // largest transform only, since the largest transform block size is 64x64.
  int tx_size_search_lgr_block;

  TX_TYPE_SEARCH tx_type_search;

  // Skip split transform block partition when the collocated bigger block
  // is selected as all zero coefficients.
  int txb_split_cap;

  // Shortcut the transform block partition and type search when the target
  // rdcost is relatively lower.
  // Values are 0 (not used) , or 1 - 2 with progressively increasing
  // aggressiveness
  int adaptive_txb_search_level;

  // Prune level for tx_size_type search for inter based on rd model
  // 0: no pruning
  // 1-2: progressively increasing aggressiveness of pruning
  int model_based_prune_tx_search_level;

  // Refine TX type after fast TX search.
  int refine_fast_tx_search_results;

  // Prune transform split/no_split eval based on residual properties. A value
  // of 0 indicates no pruning, and the aggressiveness of pruning progressively
  // increases from levels 1 to 3.
  int prune_tx_size_level;

  // Prune the evaluation of transform depths as decided by the NN model.
  // false: No pruning.
  // true : Avoid the evaluation of specific transform depths using NN model.
  //
  // For allintra encode, this speed feature reduces instruction count
  // by 4.76%, 8.92% and 11.28% for speed 6, 7 and 8 with coding performance
  // change less than 0.32%. For AVIF image encode, this speed feature reduces
  // encode time by 4.65%, 9.16% and 10.45% for speed 6, 7 and 8 on a typical
  // image dataset with coding performance change less than 0.19%.
  bool prune_intra_tx_depths_using_nn;

  // Enable/disable early breakout during transform search of intra modes, by
  // using the minimum rd cost possible. By using this approach, the rd
  // evaluation of applicable transform blocks (in the current block) can be
  // avoided as
  // 1) best_rd evolves during the search in choose_tx_size_type_from_rd()
  // 2) appropriate ref_best_rd is passed in intra_block_yrd()
  //
  // For allintra encode, this speed feature reduces instruction count
  // by 1.11%, 1.08%, 1.02% and 0.93% for speed 3, 6, 7 and 8 with coding
  // performance change less than 0.02%. For AVIF image encode, this speed
  // feature reduces encode time by 0.93%, 1.46%, 1.07%, 0.84%, 0.99% and 0.73%
  // for speed 3, 4, 5, 6, 7 and 8 on a typical image dataset with coding
  // performance change less than 0.004%.
  bool use_rd_based_breakout_for_intra_tx_search;

  // Prune RD evaluation of transform split using RD Costs of transform no-split
  // of inter modes that are evaluated so far.
  // Values are 0 (not used),  1 - 2 with progressively increasing
  // aggressiveness, i.e., decreasing number of top candidates
  int prune_inter_tx_split_rd_eval_lvl;

  // If 1, use a trellis rd multiplier that favors chroma plane more.
  int use_chroma_trellis_rd_mult;
} TX_SPEED_FEATURES;

typedef struct RD_CALC_SPEED_FEATURES {
  // Fast approximation of av1_model_rd_from_var_lapndz
  int simple_model_rd_from_var;

  // Perform faster distortion computation during the R-D evaluation by trying
  // to approximate the prediction error with transform coefficients (faster but
  // less accurate) rather than computing distortion in the pixel domain (slower
  // but more accurate). The following methods are used for distortion
  // computation:
  // Method 0: Always compute distortion in the pixel domain
  // Method 1: Based on block error, try using transform domain distortion for
  // tx_type search and compute distortion in pixel domain for final RD_STATS
  // Method 2: Based on block error, try to compute distortion in transform
  // domain
  // Methods 1 and 2 may fallback to computing distortion in the pixel domain in
  // case the block error is less than the threshold, which is controlled by the
  // speed feature tx_domain_dist_thres_level.
  //
  // The speed feature tx_domain_dist_level decides which of the above methods
  // needs to be used across different mode evaluation stages as described
  // below:
  // Eval type:    Default      Mode        Winner
  // Level 0  :    Method 0    Method 2    Method 0
  // Level 1  :    Method 1    Method 2    Method 0
  // Level 2  :    Method 2    Method 2    Method 0
  // Level 3  :    Method 2    Method 2    Method 2
  int tx_domain_dist_level;

  // Transform domain distortion threshold level
  int tx_domain_dist_thres_level;

  // Trellis (dynamic programming) optimization of quantized values
  TRELLIS_OPT_TYPE optimize_coefficients;

  // Use hash table to store macroblock RD search results
  // to avoid repeated search on the same residue signal.
  int use_mb_rd_hash;

  // Flag used to control the extent of coeff R-D optimization
  int perform_coeff_opt;
} RD_CALC_SPEED_FEATURES;

typedef struct WINNER_MODE_SPEED_FEATURES {
  // Flag used to control the winner mode processing for better R-D optimization
  // of quantized coeffs
  int enable_winner_mode_for_coeff_opt;

  // Flag used to control the winner mode processing for transform size
  // search method
  int enable_winner_mode_for_tx_size_srch;

  // Control transform size search level
  // Eval type: Default       Mode        Winner
  // Level 0  : FULL RD     LARGEST ALL   FULL RD
  // Level 1  : FAST RD     LARGEST ALL   FULL RD
  // Level 2  : LARGEST ALL LARGEST ALL   FULL RD
  // Level 3 :  LARGEST ALL LARGEST ALL   LARGEST ALL
  int tx_size_search_level;

  // Flag used to control the winner mode processing for use transform
  // domain distortion
  int enable_winner_mode_for_use_tx_domain_dist;

  // Flag used to enable processing of multiple winner modes
  MULTI_WINNER_MODE_TYPE multi_winner_mode_type;

  // Motion mode for winner candidates:
  // 0: speed feature OFF
  // 1 / 2 : Use configured number of winner candidates
  int motion_mode_for_winner_cand;

  // Controls the prediction of transform skip block or DC only block.
  //
  // Different speed feature values (0 to 3) decide the aggressiveness of
  // prediction (refer to predict_dc_levels[][] in speed_features.c) to be used
  // during different mode evaluation stages.
  int dc_blk_pred_level;

  // If on, disables interpolation filter search in handle_inter_mode loop, and
  // performs it during winner mode processing by \ref
  // tx_search_best_inter_candidates.
  int winner_mode_ifs;

  // Controls the disabling of winner mode processing. Speed feature levels
  // are ordered in increasing aggressiveness of pruning. The method considered
  // for disabling, depends on the sf level value and it is described as below.
  // 0: Do not disable
  // 1: Disable for blocks with low source variance.
  // 2: Disable for blocks which turn out to be transform skip (skipped based on
  // eob) during MODE_EVAL stage except NEWMV mode.
  // 3: Disable for blocks which turn out to be transform skip during MODE_EVAL
  // stage except NEWMV mode. For high quantizers, prune conservatively based on
  // transform skip (skipped based on eob) except for NEWMV mode.
  // 4: Disable for blocks which turn out to be transform skip during MODE_EVAL
  // stage.
  int prune_winner_mode_eval_level;
} WINNER_MODE_SPEED_FEATURES;

typedef struct LOOP_FILTER_SPEED_FEATURES {
  // This feature controls how the loop filter level is determined.
  LPF_PICK_METHOD lpf_pick;

  // Skip some final iterations in the determination of the best loop filter
  // level.
  int use_coarse_filter_level_search;

  // Reset luma filter levels to zero based on minimum filter levels of
  // reference frames and current frame's pyramid level.
  int adaptive_luma_loop_filter_skip;

  // Reset luma filter levels to zero when the percentage of SSE difference
  // between the unfiltered and filtered versions of the current frame is below
  // a threshold.
  int skip_loop_filter_using_filt_error;

  // Control how the CDEF strength is determined.
  CDEF_PICK_METHOD cdef_pick_method;

  // Decoder side speed feature for adaptive CDEF with strength reduction.
  // Zero out values with low CDEF strengths (luma and/or chroma). This is
  // done as CDEF is a relatively-expensive filter to compute during decode.
  // This speed feature is only enabled in all intra mode.
  bool zero_low_cdef_strengths;

  // Decoder side speed feature for adaptive CDEF control based on MSE
  // 0 : Enable CDEF for all planes
  // 1 : Disable CDEF for chroma planes and disable for luma adaptively based on
  //     current frame's pyramid level and improvement in MSE after CDEF
  //     filtering.
  int adaptive_cdef_mode;

  // Decoder side speed feature to add penalty for use of dual-sgr filters.
  // Takes values 0 - 10, 0 indicating no penalty and each additional level
  // adding a penalty of 1%
  int dual_sgr_penalty_level;

  // Restricts loop restoration to RESTORE_SWITCHABLE by skipping RD cost
  // comparisons for RESTORE_WIENER and RESTORE_SGRPROJ. Also applies a bias
  // during switchable restoration search: each level adds a 0.5% penalty to
  // Wiener and SGR selection.
  // 0 : No restriction or bias (all restoration types allowed)
  // 1+: Skip WIENER/SGRPROJ and apply (level x 0.5%) penalty in
  // search_switchable()
  int switchable_lr_with_bias_level;

  // Enable fast search in self guided restoration
  // 0 : Search over all 16 SGR projection parameters listed
  //     in av1_sgr_params[SGRPROJ_PARAMS].
  // 1 : Approximate search using binary search like mechanism,
  //     a total of 8 SGR projection parameters are searched.
  // 2 : Search only 'ep' values in
  //     sgproj_ep_grp1_seed[SGRPROJ_EP_GRP1_SEARCH_COUNT],
  //     a total of 4 SGR projection parameters are searched.
  int enable_sgr_ep_pruning;

  // Disable loop restoration for Chroma plane
  int disable_loop_restoration_chroma;

  // Disable loop restoration for luma plane
  int disable_loop_restoration_luma;

  // Range of loop restoration unit sizes to search
  // The minimum size is clamped against the superblock size in
  // av1_pick_filter_restoration, so that the code which sets this value does
  // not need to know the superblock size ahead of time.
  int min_lr_unit_size;
  int max_lr_unit_size;

  // Prune RESTORE_WIENER evaluation based on source variance
  // 0 : no pruning
  // 1 : conservative pruning
  // 2 : aggressive pruning
  int prune_wiener_based_on_src_var;

  // Prune self-guided loop restoration based on wiener search results
  // 0 : no pruning
  // 1 : pruning based on rdcost ratio of RESTORE_WIENER and RESTORE_NONE
  // 2 : pruning based on winner restoration type among RESTORE_WIENER and
  // RESTORE_NONE
  int prune_sgr_based_on_wiener;

  // Reduce the wiener filter win size for luma
  int reduce_wiener_window_size;

  // Flag to disable Wiener Loop restoration filter.
  bool disable_wiener_filter;

  // Flag to disable Self-guided Loop restoration filter.
  bool disable_sgr_filter;

  // Disable the refinement search around the wiener filter coefficients.
  bool disable_wiener_coeff_refine_search;

  // Whether to downsample the rows in computation of wiener stats.
  int use_downsampled_wiener_stats;
} LOOP_FILTER_SPEED_FEATURES;

typedef struct REAL_TIME_SPEED_FEATURES {
  // check intra prediction for non-RD mode.
  int check_intra_pred_nonrd;

  // Skip checking intra prediction.
  // 0 - don't skip
  // 1 - skip if TX is skipped and best mode is not NEWMV
  // 2 - skip if TX is skipped
  // Skipping aggressiveness increases from level 1 to 2.
  int skip_intra_pred;

  // Estimate motion before calculating variance in variance-based partition
  // 0 - Only use zero MV
  // 1 - perform coarse ME
  // 2 - perform coarse ME, and also use neighbours' MVs
  // 3 - use neighbours' MVs without performing coarse ME
  int estimate_motion_for_var_based_partition;

  // For nonrd_use_partition: mode of extra check of leaf partition
  // 0 - don't check merge
  // 1 - always check merge
  // 2 - check merge and prune checking final split
  // 3 - check merge and prune checking final split based on bsize and qindex
  int nonrd_check_partition_merge_mode;

  // For nonrd_use_partition: check of leaf partition extra split
  int nonrd_check_partition_split;

  // Implements various heuristics to skip searching modes
  // The heuristics selected are based on  flags
  // defined in the MODE_SEARCH_SKIP_HEURISTICS enum
  unsigned int mode_search_skip_flags;

  // For nonrd: Reduces ref frame search.
  // 0 - low level of search prune in non last frames
  // 1 - pruned search in non last frames
  // 2 - more pruned search in non last frames
  int nonrd_prune_ref_frame_search;

  // This flag controls the use of non-RD mode decision.
  int use_nonrd_pick_mode;

  // Flag that controls discounting for color map cost during palette search.
  // This saves about 5% of CPU and in non-RD speeds delivers better results
  // across rtc_screen set (on speed 10 overall BDRate growth is 13%)
  int discount_color_cost;

  // Use ALTREF frame in non-RD mode decision.
  int use_nonrd_altref_frame;

  // Use compound reference for non-RD mode.
  int use_comp_ref_nonrd;

  // Reference frames for compound prediction for nonrd pickmode:
  // LAST_GOLDEN (0), LAST_LAST2 (1), or LAST_ALTREF (2).
  int ref_frame_comp_nonrd[3];

  // use reduced ref set for real-time mode
  int use_real_time_ref_set;

  // Skip a number of expensive mode evaluations for blocks with very low
  // temporal variance.
  int short_circuit_low_temp_var;

  // Reuse inter prediction in fast non-rd mode.
  int reuse_inter_pred_nonrd;

  // Number of best inter modes to search transform. INT_MAX - search all.
  int num_inter_modes_for_tx_search;

  // Use interpolation filter search in non-RD mode decision.
  int use_nonrd_filter_search;

  // Use simplified RD model for interpolation search and Intra
  int use_simple_rd_model;

  // For nonrd mode: use hybrid intra mode search for intra only frames based on
  // block properties.
  // 0 : use nonrd pick intra for all blocks
  // 1 : use rd for bsize < 16x16, nonrd otherwise
  // 2 : use rd for bsize < 16x16 and src var >= 101, nonrd otherwise
  int hybrid_intra_pickmode;

  // Filter blocks by certain criteria such as SAD, source variance, such that
  // fewer blocks will go through the palette search.
  // For nonrd encoding path, enable this feature reduces encoding time when
  // palette mode is used. Disabling it leads to better compression efficiency.
  // 0: off
  // 1: less aggressive pruning mode
  // 2, 3: more aggressive pruning mode
  int prune_palette_search_nonrd;

  // Compute variance/sse on source difference, prior to encoding superblock.
  int source_metrics_sb_nonrd;

  // Flag to indicate process for handling overshoot on slide/scene change,
  // for real-time CBR mode.
  OVERSHOOT_DETECTION_CBR overshoot_detection_cbr;

  // Check for scene/content change detection on every frame before encoding.
  int check_scene_detection;

  // For keyframes in rtc: adjust the rc_bits_per_mb, to reduce overshoot.
  int rc_adjust_keyframe;

  // On scene change or keyframe: compute spatial variance.
  int rc_compute_spatial_var_sc_kf;

  // For nonrd mode: Prefer larger partition blks in variance based partitioning
  // 0: disabled, 1-3: increasing aggressiveness
  int prefer_large_partition_blocks;

  // uses results of temporal noise estimate
  int use_temporal_noise_estimate;

  // Parameter indicating initial search window to be used in full-pixel search
  // for nonrd_pickmode. Range [0, MAX_MVSEARCH_STEPS - 1]. Lower value
  // indicates larger window. If set to 0, step_param is set based on internal
  // logic in set_mv_search_params().
  int fullpel_search_step_param;

  // Bit mask to enable or disable intra modes for each prediction block size
  // separately, for nonrd_pickmode.  Currently, the sf is not respected when
  // 'force_intra_check' is true in 'av1_estimate_intra_mode()' function. Also,
  // H and V pred modes allowed through this sf can be further pruned when
  //'prune_hv_pred_modes_using_src_sad' sf is true.
  int intra_y_mode_bsize_mask_nrd[BLOCK_SIZES];

  // Prune H and V intra predition modes evalution in inter frame.
  // The sf does not have any impact.
  // i. when frame_source_sad is 1.1 times greater than avg_source_sad
  // ii. when cyclic_refresh_segment_id_boosted is enabled
  // iii. when SB level source sad is greater than kMedSad
  // iv. when color sensitivity is non zero for both the chroma channels
  bool prune_hv_pred_modes_using_src_sad;

  // Skips mode checks more aggressively in nonRD mode
  int nonrd_aggressive_skip;

  // Skip cdef on 64x64 blocks/
  // 0: disabled
  // 1: skip when NEWMV or INTRA is not picked or color sensitivity is off.
  // When color sensitivity is on for a superblock, all 64x64 blocks within
  // will not skip.
  // 2: more aggressive mode where skip is done for all frames where
  // rc->high_source_sad = 0 (non slide-changes), and color sensitivity off.
  int skip_cdef_sb;

  // Force selective cdf update.
  int selective_cdf_update;

  // Force only single reference (LAST) for prediction.
  int force_only_last_ref;

  // Forces larger partition blocks in variance based partitioning for intra
  // frames
  int force_large_partition_blocks_intra;

  // Use fixed partition for superblocks based on source_sad.
  // 0: disabled
  // 1: enabled
  int use_fast_fixed_part;

  // Increase source_sad thresholds in nonrd pickmode.
  int increase_source_sad_thresh;

  // Skip evaluation of no split in tx size selection for merge partition
  int skip_tx_no_split_var_based_partition;

  // Intermediate termination of newMV mode evaluation based on so far best mode
  // sse
  int skip_newmv_mode_based_on_sse;

  // Define gf length multiplier.
  // Level 0: use large multiplier, level 1: use medium multiplier.
  int gf_length_lvl;

  // Prune inter modes with golden frame as reference for NEARMV and NEWMV modes
  int prune_inter_modes_with_golden_ref;

  // Prune inter modes w.r.t golden or alt-ref frame based on sad
  int prune_inter_modes_wrt_gf_arf_based_on_sad;

  // Prune inter mode search in rd path based on current block's temporal
  // variance wrt LAST reference.
  int prune_inter_modes_using_temp_var;

  // Reduce MV precision to halfpel for higher int MV value & frame-level motion
  // 0: disabled
  // 1-2: Reduce precision to halfpel, fullpel based on conservative
  // thresholds, aggressiveness increases with increase in level
  // 3: Reduce precision to halfpel using more aggressive thresholds
  int reduce_mv_pel_precision_highmotion;

  // Reduce MV precision for low complexity blocks
  // 0: disabled
  // 1: Reduce the mv resolution for zero mv if the variance is low
  // 2: Switch to halfpel, fullpel based on low block spatial-temporal
  // complexity.
  int reduce_mv_pel_precision_lowcomplex;

  // Prune intra mode evaluation in inter frames based on mv range.
  BLOCK_SIZE prune_intra_mode_based_on_mv_range;
  // The number of times to left shift the splitting thresholds in variance
  // based partitioning. The minimum values should be 7 to avoid left shifting
  // by a negative number.
  int var_part_split_threshold_shift;

  // Qindex based variance partition threshold index, which determines
  // the aggressiveness of partition pruning
  // 0: disabled for speeds 9,10
  // 1,2: (rd-path) lowers qindex thresholds conditionally (for low SAD sb)
  // 3,4: (non-rd path) uses pre-tuned qindex thresholds
  int var_part_based_on_qidx;

  // Enable GF refresh based on Q value.
  int gf_refresh_based_on_qp;

  // Temporal filtering
  // The value can be 1 or 2, which indicates the threshold to use.
  // Must be off for lossless mode.
  int use_rtc_tf;

  // Use of the identity transform in nonrd_pickmode,
  int use_idtx_nonrd;

  // Prune the use of the identity transform in nonrd_pickmode:
  // only for smaller blocks and higher spatial variance, and when skip_txfm
  // is not already set.
  int prune_idtx_nonrd;

  // Force to only use dct for palette search in nonrd pickmode.
  int dct_only_palette_nonrd;

  // Skip loopfilter, for static content after slide change
  // or key frame, once quality has ramped up.
  // 0: disabled
  // 1: skip only after quality is ramped up.
  // 2: aggrssive mode, where skip is done for all frames that
  // where rc->high_source_sad = 0 (no slide-changes).
  int skip_lf_screen;

  // Threshold on the active/inactive region percent to disable
  // the loopfilter and cdef. Setting to 100 disables this feature.
  int thresh_active_maps_skip_lf_cdef;

  // For nonrd: early exit out of variance partition that sets the
  // block size to superblock size, and sets mode to zeromv-last skip.
  // 0: disabled
  // 1: zeromv-skip is enabled at SB level only
  // 2: zeromv-skip is enabled at SB level and coding block level
  int part_early_exit_zeromv;

  // Early terminate inter mode search based on sse in non-rd path.
  INTER_SEARCH_EARLY_TERM_IDX sse_early_term_inter_search;

  // SAD based adaptive altref selection
  int sad_based_adp_altref_lag;

  // Enable/disable partition direct merging.
  int partition_direct_merging;

  // Level of aggressiveness for obtaining tx size based on qstep
  int tx_size_level_based_on_qstep;

  // Avoid the partitioning of a 16x16 block in variance based partitioning
  // (VBP) by making use of minimum and maximum sub-block variances.
  // For allintra encode, this speed feature reduces instruction count by 5.39%
  // for speed 9 on a typical video dataset with coding performance gain
  // of 1.44%.
  // For AVIF image encode, this speed feature reduces encode time
  // by 8.44% for speed 9 on a typical image dataset with coding performance
  // gain of 0.78%.
  bool vbp_prune_16x16_split_using_min_max_sub_blk_var;

  // A qindex threshold that determines whether to use qindex based CDEF filter
  // strength estimation for screen content types. The strength estimation model
  // used for screen contents prefers to allow cdef filtering for more frames.
  // This sf is used to limit the frames which go through cdef filtering and
  // following explains the setting of the same.
  // MAXQ (255): This disables the usage of this sf. Here, frame does not use a
  // screen content model thus reduces the number of frames that go through cdef
  // filtering.
  // MINQ (0): Frames always use screen content model thus increasing the number
  // of frames that go through cdef filtering.
  // This speed feature has a substantial gain on coding metrics, with moderate
  // increase encoding time. Select threshold based on speed vs quality
  // trade-off.
  int screen_content_cdef_filter_qindex_thresh;

  // Prune compound mode if its variance is higher than the variance of single
  // modes.
  bool prune_compoundmode_with_singlecompound_var;

  // Allow mode cost update at frame level every couple frames. This
  // overrides the command line setting --mode-cost-upd-freq=3 (never update
  // except on key frame and first delta).
  bool frame_level_mode_cost_update;

  // Prune H_PRED during intra mode evaluation in the nonrd path based on best
  // mode so far.
  //
  // For allintra encode, this speed feature reduces instruction count by 1.10%
  // for speed 9 with coding performance change less than 0.04%.
  // For AVIF image encode, this speed feature reduces encode time by 1.03% for
  // speed 9 on a typical image dataset with coding performance change less than
  // 0.08%.
  bool prune_h_pred_using_best_mode_so_far;

  // Enable pruning of intra mode evaluations in nonrd path based on source
  // variance and best mode so far. The pruning logic is enabled only if the
  // mode is not a winner mode of both the neighboring blocks (left/top).
  //
  // For allintra encode, this speed feature reduces instruction count by 3.96%
  // for speed 9 with coding performance change less than 0.38%.
  // For AVIF image encode, this speed feature reduces encode time by 3.46% for
  // speed 9 on a typical image dataset with coding performance change less than
  // -0.06%.
  bool enable_intra_mode_pruning_using_neighbors;

  // Prune intra mode evaluations in nonrd path based on best sad so far.
  //
  // For allintra encode, this speed feature reduces instruction count by 3.05%
  // for speed 9 with coding performance change less than 0.24%.
  // For AVIF image encode, this speed feature reduces encode time by 1.87% for
  // speed 9 on a typical image dataset with coding performance change less than
  // 0.16%.
  bool prune_intra_mode_using_best_sad_so_far;

  // If compound is enabled, and the current block size is \geq BLOCK_16X16,
  // limit the compound modes to GLOBAL_GLOBALMV. This does not apply to the
  // base layer of svc.
  bool check_only_zero_zeromv_on_large_blocks;

  // Allow for disabling cdf update for non reference frames in svc mode.
  bool disable_cdf_update_non_reference_frame;

  // Prune compound modes if the single modes variances do not perform well.
  bool prune_compoundmode_with_singlemode_var;

  // Skip searching all compound mode if the variance of single_mode residue is
  // sufficiently low.
  bool skip_compound_based_on_var;

  // Sets force_zeromv_skip based on the source sad available. Aggressiveness
  // increases with increase in the level set for speed feature.
  // 0: No setting
  // 1: If source sad is kZeroSad
  // 2: If source sad <= kVeryLowSad
  int set_zeromv_skip_based_on_source_sad;

  // Downgrades the block-level subpel motion search to
  // av1_find_best_sub_pixel_tree_pruned_more for higher QP and when fullpel
  // search performed well, zeromv has low sad or low source_var
  bool use_adaptive_subpel_search;

  // A flag used in RTC case to control frame_refs_short_signaling. Note that
  // the final decision is made in check_frame_refs_short_signaling(). The flag
  // can only be turned on when res < 360p and speed >= 9, in which case only
  // LAST and GOLDEN ref frames are used now.
  bool enable_ref_short_signaling;

  // A flag that controls if we check or bypass GLOBALMV in rtc single ref frame
  // case.
  bool check_globalmv_on_single_ref;

  // Allows for increasing the color_threshold for palette prediction.
  // This generally leads to better coding efficiency but with some speed loss.
  // Only used for screen content and for nonrd_pickmode.
  bool increase_color_thresh_palette;

  // Flag to indicate selecting of higher threshold for scenee change detection.
  int higher_thresh_scene_detection;

  // FLag to indicate skip testing of NEWMV for flat blocks.
  int skip_newmv_flat_blocks_screen;

  // Flag to force skip encoding for non_reference_frame on slide/scene changes.
  int skip_encoding_non_reference_slide_change;

  // Flag to indicate more aggressive QP downward adjustment for screen static
  // content, to make convergence to min_qp faster.
  int rc_faster_convergence_static;

  // Skip NEWMV mode evaluation based on sad for screen content.
  int skip_newmv_mode_sad_screen;
} REAL_TIME_SPEED_FEATURES;

typedef struct SPEED_FEATURES {
  HIGH_LEVEL_SPEED_FEATURES hl_sf;

  FIRST_PASS_SPEED_FEATURES fp_sf;

  TPL_SPEED_FEATURES tpl_sf;

  GLOBAL_MOTION_SPEED_FEATURES gm_sf;

  PARTITION_SPEED_FEATURES part_sf;

  MV_SPEED_FEATURES mv_sf;

  INTER_MODE_SPEED_FEATURES inter_sf;

  INTERP_FILTER_SPEED_FEATURES interp_sf;

  INTRA_MODE_SPEED_FEATURES intra_sf;

  TX_SPEED_FEATURES tx_sf;

  RD_CALC_SPEED_FEATURES rd_sf;

  WINNER_MODE_SPEED_FEATURES winner_mode_sf;

  LOOP_FILTER_SPEED_FEATURES lpf_sf;

  REAL_TIME_SPEED_FEATURES rt_sf;
} SPEED_FEATURES;
struct AV1_COMP;

void av1_set_speed_features_framesize_independent(struct AV1_COMP *cpi,
                                                  int speed);

void av1_set_speed_features_framesize_dependent(struct AV1_COMP *cpi,
                                                int speed);
void av1_set_speed_features_qindex_dependent(struct AV1_COMP *cpi, int speed);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // AOM_AV1_ENCODER_SPEED_FEATURES_H_