/*
 * Copyright (c) 2019, 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 "aom_ports/system_state.h"

#include "av1/encoder/encoder.h"
#include "av1/encoder/level.h"

#define UNDEFINED_LEVEL                                                 \
  {                                                                     \
    .level = SEQ_LEVEL_MAX, .max_picture_size = 0, .max_h_size = 0,     \
    .max_v_size = 0, .max_display_rate = 0, .max_decode_rate = 0,       \
    .max_header_rate = 0, .main_mbps = 0, .high_mbps = 0, .main_cr = 0, \
    .high_cr = 0, .max_tiles = 0, .max_tile_cols = 0                    \
  }

static const AV1LevelSpec av1_level_defs[SEQ_LEVELS] = {
  { .level = SEQ_LEVEL_2_0,
    .max_picture_size = 147456,
    .max_h_size = 2048,
    .max_v_size = 1152,
    .max_display_rate = 4423680L,
    .max_decode_rate = 5529600L,
    .max_header_rate = 150,
    .main_mbps = 1.5,
    .high_mbps = 0,
    .main_cr = 2.0,
    .high_cr = 0,
    .max_tiles = 8,
    .max_tile_cols = 4 },
  { .level = SEQ_LEVEL_2_1,
    .max_picture_size = 278784,
    .max_h_size = 2816,
    .max_v_size = 1584,
    .max_display_rate = 8363520L,
    .max_decode_rate = 10454400L,
    .max_header_rate = 150,
    .main_mbps = 3.0,
    .high_mbps = 0,
    .main_cr = 2.0,
    .high_cr = 0,
    .max_tiles = 8,
    .max_tile_cols = 4 },
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
  { .level = SEQ_LEVEL_3_0,
    .max_picture_size = 665856,
    .max_h_size = 4352,
    .max_v_size = 2448,
    .max_display_rate = 19975680L,
    .max_decode_rate = 24969600L,
    .max_header_rate = 150,
    .main_mbps = 6.0,
    .high_mbps = 0,
    .main_cr = 2.0,
    .high_cr = 0,
    .max_tiles = 16,
    .max_tile_cols = 6 },
  { .level = SEQ_LEVEL_3_1,
    .max_picture_size = 1065024,
    .max_h_size = 5504,
    .max_v_size = 3096,
    .max_display_rate = 31950720L,
    .max_decode_rate = 39938400L,
    .max_header_rate = 150,
    .main_mbps = 10.0,
    .high_mbps = 0,
    .main_cr = 2.0,
    .high_cr = 0,
    .max_tiles = 16,
    .max_tile_cols = 6 },
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
  { .level = SEQ_LEVEL_4_0,
    .max_picture_size = 2359296,
    .max_h_size = 6144,
    .max_v_size = 3456,
    .max_display_rate = 70778880L,
    .max_decode_rate = 77856768L,
    .max_header_rate = 300,
    .main_mbps = 12.0,
    .high_mbps = 30.0,
    .main_cr = 4.0,
    .high_cr = 4.0,
    .max_tiles = 32,
    .max_tile_cols = 8 },
  { .level = SEQ_LEVEL_4_1,
    .max_picture_size = 2359296,
    .max_h_size = 6144,
    .max_v_size = 3456,
    .max_display_rate = 141557760L,
    .max_decode_rate = 155713536L,
    .max_header_rate = 300,
    .main_mbps = 20.0,
    .high_mbps = 50.0,
    .main_cr = 4.0,
    .high_cr = 4.0,
    .max_tiles = 32,
    .max_tile_cols = 8 },
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
  { .level = SEQ_LEVEL_5_0,
    .max_picture_size = 8912896,
    .max_h_size = 8192,
    .max_v_size = 4352,
    .max_display_rate = 267386880L,
    .max_decode_rate = 273715200L,
    .max_header_rate = 300,
    .main_mbps = 30.0,
    .high_mbps = 100.0,
    .main_cr = 6.0,
    .high_cr = 4.0,
    .max_tiles = 64,
    .max_tile_cols = 8 },
  { .level = SEQ_LEVEL_5_1,
    .max_picture_size = 8912896,
    .max_h_size = 8192,
    .max_v_size = 4352,
    .max_display_rate = 534773760L,
    .max_decode_rate = 547430400L,
    .max_header_rate = 300,
    .main_mbps = 40.0,
    .high_mbps = 160.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 64,
    .max_tile_cols = 8 },
  { .level = SEQ_LEVEL_5_2,
    .max_picture_size = 8912896,
    .max_h_size = 8192,
    .max_v_size = 4352,
    .max_display_rate = 1069547520L,
    .max_decode_rate = 1094860800L,
    .max_header_rate = 300,
    .main_mbps = 60.0,
    .high_mbps = 240.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 64,
    .max_tile_cols = 8 },
  { .level = SEQ_LEVEL_5_3,
    .max_picture_size = 8912896,
    .max_h_size = 8192,
    .max_v_size = 4352,
    .max_display_rate = 1069547520L,
    .max_decode_rate = 1176502272L,
    .max_header_rate = 300,
    .main_mbps = 60.0,
    .high_mbps = 240.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 64,
    .max_tile_cols = 8 },
  { .level = SEQ_LEVEL_6_0,
    .max_picture_size = 35651584,
    .max_h_size = 16384,
    .max_v_size = 8704,
    .max_display_rate = 1069547520L,
    .max_decode_rate = 1176502272L,
    .max_header_rate = 300,
    .main_mbps = 60.0,
    .high_mbps = 240.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 128,
    .max_tile_cols = 16 },
  { .level = SEQ_LEVEL_6_1,
    .max_picture_size = 35651584,
    .max_h_size = 16384,
    .max_v_size = 8704,
    .max_display_rate = 2139095040L,
    .max_decode_rate = 2189721600L,
    .max_header_rate = 300,
    .main_mbps = 100.0,
    .high_mbps = 480.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 128,
    .max_tile_cols = 16 },
  { .level = SEQ_LEVEL_6_2,
    .max_picture_size = 35651584,
    .max_h_size = 16384,
    .max_v_size = 8704,
    .max_display_rate = 4278190080L,
    .max_decode_rate = 4379443200L,
    .max_header_rate = 300,
    .main_mbps = 160.0,
    .high_mbps = 800.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 128,
    .max_tile_cols = 16 },
  { .level = SEQ_LEVEL_6_3,
    .max_picture_size = 35651584,
    .max_h_size = 16384,
    .max_v_size = 8704,
    .max_display_rate = 4278190080L,
    .max_decode_rate = 4706009088L,
    .max_header_rate = 300,
    .main_mbps = 160.0,
    .high_mbps = 800.0,
    .main_cr = 8.0,
    .high_cr = 4.0,
    .max_tiles = 128,
    .max_tile_cols = 16 },
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
  UNDEFINED_LEVEL,
};

typedef enum {
  LUMA_PIC_SIZE_TOO_LARGE,
  LUMA_PIC_H_SIZE_TOO_LARGE,
  LUMA_PIC_V_SIZE_TOO_LARGE,
  LUMA_PIC_H_SIZE_TOO_SMALL,
  LUMA_PIC_V_SIZE_TOO_SMALL,
  TOO_MANY_TILE_COLUMNS,
  TOO_MANY_TILES,
  TILE_RATE_TOO_HIGH,
  TILE_TOO_LARGE,
  SUPERRES_TILE_WIDTH_TOO_LARGE,
  CROPPED_TILE_WIDTH_TOO_SMALL,
  CROPPED_TILE_HEIGHT_TOO_SMALL,
  TILE_WIDTH_INVALID,
  FRAME_HEADER_RATE_TOO_HIGH,
  DISPLAY_RATE_TOO_HIGH,
  DECODE_RATE_TOO_HIGH,
  CR_TOO_SMALL,
  TILE_SIZE_HEADER_RATE_TOO_HIGH,

  TARGET_LEVEL_FAIL_IDS,
  TARGET_LEVEL_OK,
} TARGET_LEVEL_FAIL_ID;

static const char *level_fail_messages[TARGET_LEVEL_FAIL_IDS] = {
  "The picture size is too large.",
  "The picture width is too large.",
  "The picture height is too large.",
  "The picture width is too small.",
  "The picture height is too small.",
  "Too many tile columns are used.",
  "Too many tiles are used.",
  "The tile rate is too high.",
  "The tile size is too large.",
  "The superres tile width is too large.",
  "The cropped tile width is less than 8.",
  "The cropped tile height is less than 8.",
  "The tile width is invalid.",
  "The frame header rate is too high.",
  "The display luma sample rate is too high.",
  "The decoded luma sample rate is too high.",
  "The compression ratio is too small.",
  "The product of max tile size and header rate is too high.",
};

static double get_min_cr(const AV1LevelSpec *const level_spec, int tier,
                         int is_still_picture, int64_t decoded_sample_rate) {
  if (is_still_picture) return 0.8;
  if (level_spec->level < SEQ_LEVEL_4_0) tier = 0;
  const double min_cr_basis = tier ? level_spec->high_cr : level_spec->main_cr;
  const double speed_adj =
      (double)decoded_sample_rate / level_spec->max_display_rate;
  return AOMMAX(min_cr_basis * speed_adj, 0.8);
}

static void get_temporal_parallel_params(int scalability_mode_idc,
                                         int *temporal_parallel_num,
                                         int *temporal_parallel_denom) {
  if (scalability_mode_idc < 0) {
    *temporal_parallel_num = 1;
    *temporal_parallel_denom = 1;
    return;
  }

  // TODO(huisu@): handle scalability cases.
  if (scalability_mode_idc == SCALABILITY_SS) {
    (void)scalability_mode_idc;
  } else {
    (void)scalability_mode_idc;
  }
}

#define MAX_TILE_SIZE (4096 * 2304)
#define MIN_CROPPED_TILE_WIDTH 8
#define MIN_CROPPED_TILE_HEIGHT 8
#define MIN_FRAME_WIDTH 16
#define MIN_FRAME_HEIGHT 16
#define MAX_TILE_SIZE_HEADER_RATE_PRODUCT 588251136

static TARGET_LEVEL_FAIL_ID check_level_constraints(
    const AV1LevelSpec *const target_level_spec,
    const AV1LevelSpec *const level_spec,
    const AV1LevelStats *const level_stats, int tier, int is_still_picture) {
  const double min_cr = get_min_cr(target_level_spec, tier, is_still_picture,
                                   level_spec->max_decode_rate);
  TARGET_LEVEL_FAIL_ID fail_id = TARGET_LEVEL_OK;

  do {
    if (level_spec->max_picture_size > target_level_spec->max_picture_size) {
      fail_id = LUMA_PIC_SIZE_TOO_LARGE;
      break;
    }

    if (level_spec->max_h_size > target_level_spec->max_h_size) {
      fail_id = LUMA_PIC_H_SIZE_TOO_LARGE;
      break;
    }

    if (level_spec->max_v_size > target_level_spec->max_v_size) {
      fail_id = LUMA_PIC_V_SIZE_TOO_LARGE;
      break;
    }

    if (level_spec->max_tile_cols > target_level_spec->max_tile_cols) {
      fail_id = TOO_MANY_TILE_COLUMNS;
      break;
    }

    if (level_spec->max_tiles > target_level_spec->max_tiles) {
      fail_id = TOO_MANY_TILES;
      break;
    }

    if (level_spec->max_header_rate > target_level_spec->max_header_rate) {
      fail_id = FRAME_HEADER_RATE_TOO_HIGH;
      break;
    }

    if (level_spec->max_display_rate > target_level_spec->max_display_rate) {
      fail_id = DISPLAY_RATE_TOO_HIGH;
      break;
    }

    if (level_spec->max_decode_rate > target_level_spec->max_decode_rate) {
      fail_id = DECODE_RATE_TOO_HIGH;
      break;
    }

    if (level_spec->max_tile_rate > target_level_spec->max_tiles * 120) {
      fail_id = TILE_RATE_TOO_HIGH;
      break;
    }

    if (level_stats->max_tile_size > MAX_TILE_SIZE) {
      fail_id = TILE_TOO_LARGE;
      break;
    }

    if (level_stats->max_superres_tile_width > MAX_TILE_WIDTH) {
      fail_id = SUPERRES_TILE_WIDTH_TOO_LARGE;
      break;
    }

    if (level_stats->min_cropped_tile_width < MIN_CROPPED_TILE_WIDTH) {
      fail_id = CROPPED_TILE_WIDTH_TOO_SMALL;
      break;
    }

    if (level_stats->min_cropped_tile_height < MIN_CROPPED_TILE_HEIGHT) {
      fail_id = CROPPED_TILE_HEIGHT_TOO_SMALL;
      break;
    }

    if (level_stats->min_frame_width < MIN_FRAME_WIDTH) {
      fail_id = LUMA_PIC_H_SIZE_TOO_SMALL;
      break;
    }

    if (level_stats->min_frame_height < MIN_FRAME_HEIGHT) {
      fail_id = LUMA_PIC_V_SIZE_TOO_SMALL;
      break;
    }

    if (!level_stats->tile_width_is_valid) {
      fail_id = TILE_WIDTH_INVALID;
      break;
    }

    if (level_stats->min_cr < min_cr) {
      fail_id = CR_TOO_SMALL;
      break;
    }

    if (target_level_spec->level > SEQ_LEVEL_5_1) {
      int temporal_parallel_num;
      int temporal_parallel_denom;
      const int scalability_mode_idc = -1;
      get_temporal_parallel_params(scalability_mode_idc, &temporal_parallel_num,
                                   &temporal_parallel_denom);
      const int val = level_stats->max_tile_size * level_spec->max_header_rate *
                      temporal_parallel_denom / temporal_parallel_num;
      if (val > MAX_TILE_SIZE_HEADER_RATE_PRODUCT) {
        fail_id = TILE_SIZE_HEADER_RATE_TOO_HIGH;
        break;
      }
    }
  } while (0);

  return fail_id;
}

static INLINE int is_in_operating_point(int operating_point,
                                        int temporal_layer_id,
                                        int spatial_layer_id) {
  if (!operating_point) return 1;

  return ((operating_point >> temporal_layer_id) & 1) &&
         ((operating_point >> (spatial_layer_id + 8)) & 1);
}

static void get_tile_stats(const AV1_COMP *const cpi, int *max_tile_size,
                           int *max_superres_tile_width,
                           int *min_cropped_tile_width,
                           int *min_cropped_tile_height,
                           int *tile_width_valid) {
  const AV1_COMMON *const cm = &cpi->common;
  const int tile_cols = cm->tile_cols;
  const int tile_rows = cm->tile_rows;
  const int superres_scale_denominator = cm->superres_scale_denominator;

  *max_tile_size = 0;
  *max_superres_tile_width = 0;
  *min_cropped_tile_width = INT_MAX;
  *min_cropped_tile_height = INT_MAX;
  *tile_width_valid = 1;

  for (int tile_row = 0; tile_row < tile_rows; ++tile_row) {
    for (int tile_col = 0; tile_col < tile_cols; ++tile_col) {
      const TileInfo *const tile_info =
          &cpi->tile_data[tile_row * cm->tile_cols + tile_col].tile_info;
      const int tile_width =
          (tile_info->mi_col_end - tile_info->mi_col_start) * MI_SIZE;
      const int tile_height =
          (tile_info->mi_row_end - tile_info->mi_row_start) * MI_SIZE;
      const int tile_size = tile_width * tile_height;
      *max_tile_size = AOMMAX(*max_tile_size, tile_size);

      const int supperres_tile_width =
          tile_width * superres_scale_denominator / SCALE_NUMERATOR;
      *max_superres_tile_width =
          AOMMAX(*max_superres_tile_width, supperres_tile_width);

      const int cropped_tile_width =
          cm->width - tile_info->mi_col_start * MI_SIZE;
      const int cropped_tile_height =
          cm->height - tile_info->mi_row_start * MI_SIZE;
      *min_cropped_tile_width =
          AOMMIN(*min_cropped_tile_width, cropped_tile_width);
      *min_cropped_tile_height =
          AOMMIN(*min_cropped_tile_height, cropped_tile_height);

      const int is_right_most_tile = tile_info->mi_col_end == cm->mi_cols;
      if (!is_right_most_tile) {
        if (av1_superres_scaled(cm))
          *tile_width_valid &= tile_width >= 128;
        else
          *tile_width_valid &= tile_width >= 64;
      }
    }
  }
}

static int store_frame_record(int64_t ts_start, int64_t ts_end, int pic_size,
                              int frame_header_count, int tiles, int show_frame,
                              int show_existing_frame,
                              FrameWindowBuffer *const buffer) {
  if (buffer->num < FRAME_WINDOW_SIZE) {
    ++buffer->num;
  } else {
    buffer->start = (buffer->start + 1) % FRAME_WINDOW_SIZE;
  }
  const int new_idx = (buffer->start + buffer->num - 1) % FRAME_WINDOW_SIZE;
  FrameRecord *const record = &buffer->buf[new_idx];
  record->ts_start = ts_start;
  record->ts_end = ts_end;
  record->pic_size = pic_size;
  record->frame_header_count = frame_header_count;
  record->tiles = tiles;
  record->show_frame = show_frame;
  record->show_existing_frame = show_existing_frame;

  return new_idx;
}

// Count the number of frames encoded in the last "duration" ticks, in display
// time.
static int count_frames(const FrameWindowBuffer *const buffer,
                        int64_t duration) {
  const int current_idx = (buffer->start + buffer->num - 1) % FRAME_WINDOW_SIZE;
  // Assume current frame is shown frame.
  assert(buffer->buf[current_idx].show_frame);

  const int64_t current_time = buffer->buf[current_idx].ts_end;
  const int64_t time_limit = AOMMAX(current_time - duration, 0);
  int num_frames = 1;
  int index = current_idx - 1;
  for (int i = buffer->num - 2; i >= 0; --i, --index, ++num_frames) {
    if (index < 0) index = FRAME_WINDOW_SIZE - 1;
    const FrameRecord *const record = &buffer->buf[index];
    if (!record->show_frame) continue;
    const int64_t ts_start = record->ts_start;
    if (ts_start < time_limit) break;
  }

  return num_frames;
}

// Scan previously encoded frames and update level metrics accordingly.
static void scan_past_frames(const FrameWindowBuffer *const buffer,
                             int num_frames_to_scan,
                             AV1LevelSpec *const level_spec) {
  const int num_frames_in_buffer = buffer->num;
  int index = (buffer->start + num_frames_in_buffer - 1) % FRAME_WINDOW_SIZE;
  int frame_headers = 0;
  int tiles = 0;
  int64_t display_samples = 0;
  int64_t decoded_samples = 0;
  for (int i = 0; i < AOMMIN(num_frames_in_buffer, num_frames_to_scan); ++i) {
    const FrameRecord *const record = &buffer->buf[index];
    if (!record->show_existing_frame) {
      frame_headers += record->frame_header_count;
      decoded_samples += record->pic_size;
    }
    if (record->show_frame) {
      display_samples += record->pic_size;
    }
    tiles += record->tiles;
    --index;
    if (index < 0) index = FRAME_WINDOW_SIZE - 1;
  }
  level_spec->max_header_rate =
      AOMMAX(level_spec->max_header_rate, frame_headers);
  level_spec->max_display_rate =
      AOMMAX(level_spec->max_display_rate, display_samples);
  level_spec->max_decode_rate =
      AOMMAX(level_spec->max_decode_rate, decoded_samples);
  level_spec->max_tile_rate = AOMMAX(level_spec->max_tile_rate, tiles);
}

void av1_update_level_info(AV1_COMP *cpi, size_t size, int64_t ts_start,
                           int64_t ts_end) {
  AV1_COMMON *const cm = &cpi->common;
  const int upscaled_width = cm->superres_upscaled_width;
  const int width = cm->width;
  const int height = cm->height;
  const int tile_cols = cm->tile_cols;
  const int tile_rows = cm->tile_rows;
  const int tiles = tile_cols * tile_rows;
  const int luma_pic_size = upscaled_width * height;
  const int frame_header_count = cpi->frame_header_count;
  const int show_frame = cm->show_frame;
  const int show_existing_frame = cm->show_existing_frame;

  // Store info. of current frame into FrameWindowBuffer.
  FrameWindowBuffer *const buffer = &cpi->frame_window_buffer;
  store_frame_record(ts_start, ts_end, luma_pic_size, frame_header_count, tiles,
                     show_frame, show_existing_frame, buffer);
  // Count the number of frames encoded in the past 1 second.
  const int encoded_frames_in_last_second =
      show_frame ? count_frames(buffer, TICKS_PER_SEC) : 0;

  int max_tile_size;
  int min_cropped_tile_width;
  int min_cropped_tile_height;
  int max_superres_tile_width;
  int tile_width_is_valid;
  get_tile_stats(cpi, &max_tile_size, &max_superres_tile_width,
                 &min_cropped_tile_width, &min_cropped_tile_height,
                 &tile_width_is_valid);

  const SequenceHeader *const seq_params = &cm->seq_params;
  const BITSTREAM_PROFILE profile = seq_params->profile;
  const int pic_size_profile_factor =
      profile == PROFILE_0 ? 15 : (profile == PROFILE_1 ? 30 : 36);
  const size_t frame_compressed_size = (size > 129 ? size - 128 : 1);
  const size_t frame_uncompressed_size =
      (luma_pic_size * pic_size_profile_factor) >> 3;

  aom_clear_system_state();
  const double compression_ratio =
      frame_uncompressed_size / (double)frame_compressed_size;
  const double total_time_encoded =
      (cpi->last_end_time_stamp_seen - cpi->first_time_stamp_ever) /
      (double)TICKS_PER_SEC;

  const int temporal_layer_id = cm->temporal_layer_id;
  const int spatial_layer_id = cm->spatial_layer_id;
  const int is_still_picture = seq_params->still_picture;
  // update level_stats
  // TODO(kyslov@) fix the implementation according to buffer model
  for (int i = 0; i < seq_params->operating_points_cnt_minus_1 + 1; ++i) {
    if (!is_in_operating_point(seq_params->operating_point_idc[i],
                               temporal_layer_id, spatial_layer_id)) {
      continue;
    }

    AV1LevelInfo *const level_info = &cpi->level_info[i];
    AV1LevelStats *const level_stats = &level_info->level_stats;

    level_stats->max_tile_size =
        AOMMAX(level_stats->max_tile_size, max_tile_size);
    level_stats->max_superres_tile_width =
        AOMMAX(level_stats->max_superres_tile_width, max_superres_tile_width);
    level_stats->min_cropped_tile_width =
        AOMMIN(level_stats->min_cropped_tile_width, min_cropped_tile_width);
    level_stats->min_cropped_tile_height =
        AOMMIN(level_stats->min_cropped_tile_height, min_cropped_tile_height);
    level_stats->tile_width_is_valid &= tile_width_is_valid;
    level_stats->min_frame_width = AOMMIN(level_stats->min_frame_width, width);
    level_stats->min_frame_height =
        AOMMIN(level_stats->min_frame_height, height);
    level_stats->total_compressed_size += frame_compressed_size;
    if (show_frame) level_stats->total_time_encoded = total_time_encoded;
    level_stats->min_cr = AOMMIN(level_stats->min_cr, compression_ratio);

    // update level_spec
    // TODO(kyslov@) update all spec fields
    AV1LevelSpec *const level_spec = &level_info->level_spec;
    level_spec->max_picture_size =
        AOMMAX(level_spec->max_picture_size, luma_pic_size);
    level_spec->max_h_size =
        AOMMAX(level_spec->max_h_size, cm->superres_upscaled_width);
    level_spec->max_v_size = AOMMAX(level_spec->max_v_size, height);
    level_spec->max_tile_cols = AOMMAX(level_spec->max_tile_cols, tile_cols);
    level_spec->max_tiles = AOMMAX(level_spec->max_tiles, tiles);

    if (show_frame) {
      scan_past_frames(buffer, encoded_frames_in_last_second, level_spec);
    }

    // Check whether target level is met.
    const AV1_LEVEL target_seq_level_idx = cpi->target_seq_level_idx[i];
    if (target_seq_level_idx < SEQ_LEVELS) {
      const AV1LevelSpec *const target_level_spec =
          av1_level_defs + target_seq_level_idx;
      const int tier = seq_params->tier[i];
      const TARGET_LEVEL_FAIL_ID fail_id = check_level_constraints(
          target_level_spec, level_spec, level_stats, tier, is_still_picture);
      if (fail_id != TARGET_LEVEL_OK) {
        const int target_level_major = 2 + (target_seq_level_idx >> 2);
        const int target_level_minor = target_seq_level_idx & 3;
        aom_internal_error(&cm->error, AOM_CODEC_ERROR,
                           "Failed to encode to the target level %d_%d. %s",
                           target_level_major, target_level_minor,
                           level_fail_messages[fail_id]);
      }
    }
  }
}

aom_codec_err_t av1_get_seq_level_idx(const AV1_COMP *cpi, int *seq_level_idx) {
  const SequenceHeader *const seq_params = &cpi->common.seq_params;
  if (!cpi->keep_level_stats) {
    for (int op = 0; op < seq_params->operating_points_cnt_minus_1 + 1; ++op) {
      seq_level_idx[op] = (int)SEQ_LEVEL_MAX;
    }
    return AOM_CODEC_OK;
  }

  const int is_still_picture = seq_params->still_picture;
  for (int op = 0; op < seq_params->operating_points_cnt_minus_1 + 1; ++op) {
    seq_level_idx[op] = (int)SEQ_LEVEL_MAX;
    const int tier = seq_params->tier[op];
    const AV1LevelInfo *const level_info = &cpi->level_info[op];
    const AV1LevelStats *const level_stats = &level_info->level_stats;
    const AV1LevelSpec *const level_spec = &level_info->level_spec;
    for (int level = 0; level < SEQ_LEVELS; ++level) {
      const AV1LevelSpec *const target_level_spec = av1_level_defs + level;
      const TARGET_LEVEL_FAIL_ID fail_id = check_level_constraints(
          target_level_spec, level_spec, level_stats, tier, is_still_picture);
      if (fail_id == TARGET_LEVEL_OK) {
        seq_level_idx[op] = level;
        break;
      }
    }
  }

  return AOM_CODEC_OK;
}