/*

 * Copyright (c) 2020, 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 "av1/encoder/encoder_alloc.h"

#include "av1/encoder/superres_scale.h"

#include "av1/encoder/random.h"

// Compute the horizontal frequency components' energy in a frame

// by calculuating the 16x4 Horizontal DCT. This is to be used to

// decide the superresolution parameters.

static void analyze_hor_freq(const AV1_COMP *cpi, double *energy) {

  uint64_t freq_energy[16] = { 0 };

  const YV12_BUFFER_CONFIG *buf = cpi->source;

  const int bd = cpi->td.mb.e_mbd.bd;

  const int width = buf->y_crop_width;

  const int height = buf->y_crop_height;

  DECLARE_ALIGNED(16, int32_t, coeff[16 * 4]);

  int n = 0;

  memset(freq_energy, 0, sizeof(freq_energy));

  if (buf->flags & YV12_FLAG_HIGHBITDEPTH) {

    const int16_t *src16 = (const int16_t *)CONVERT_TO_SHORTPTR(buf->y_buffer);

    for (int i = 0; i < height - 4; i += 4) {

      for (int j = 0; j < width - 16; j += 16) {

        av1_fwd_txfm2d_16x4(src16 + i * buf->y_stride + j, coeff, buf->y_stride,

                            H_DCT, bd);

        for (int k = 1; k < 16; ++k) {

          const uint64_t this_energy =

              ((int64_t)coeff[k] * coeff[k]) +

              ((int64_t)coeff[k + 16] * coeff[k + 16]) +

              ((int64_t)coeff[k + 32] * coeff[k + 32]) +

              ((int64_t)coeff[k + 48] * coeff[k + 48]);

          freq_energy[k] += ROUND_POWER_OF_TWO(this_energy, 2 + 2 * (bd - 8));

        }

        n++;

      }

    }

  } else {

    assert(bd == 8);

    DECLARE_ALIGNED(16, int16_t, src16[16 * 4]);

    for (int i = 0; i < height - 4; i += 4) {

      for (int j = 0; j < width - 16; j += 16) {

        for (int ii = 0; ii < 4; ++ii)

          for (int jj = 0; jj < 16; ++jj)

            src16[ii * 16 + jj] =

                buf->y_buffer[(i + ii) * buf->y_stride + (j + jj)];

        av1_fwd_txfm2d_16x4(src16, coeff, 16, H_DCT, bd);

        for (int k = 1; k < 16; ++k) {

          const uint64_t this_energy =

              ((int64_t)coeff[k] * coeff[k]) +

              ((int64_t)coeff[k + 16] * coeff[k + 16]) +

              ((int64_t)coeff[k + 32] * coeff[k + 32]) +

              ((int64_t)coeff[k + 48] * coeff[k + 48]);

          freq_energy[k] += ROUND_POWER_OF_TWO(this_energy, 2);

        }

        n++;

      }

    }

  }

  if (n) {

    for (int k = 1; k < 16; ++k) energy[k] = (double)freq_energy[k] / n;

    // Convert to cumulative energy

    for (int k = 14; k > 0; --k) energy[k] += energy[k + 1];

  } else {

    for (int k = 1; k < 16; ++k) energy[k] = 1e+20;

  }

}

static uint8_t calculate_next_resize_scale(const AV1_COMP *cpi) {

  // Choose an arbitrary random number

  static unsigned int seed = 56789;

  const ResizeCfg *resize_cfg = &cpi->oxcf.resize_cfg;

  if (is_stat_generation_stage(cpi)) return SCALE_NUMERATOR;

  uint8_t new_denom = SCALE_NUMERATOR;

  if (cpi->common.seq_params->reduced_still_picture_hdr) return SCALE_NUMERATOR;

  switch (resize_cfg->resize_mode) {

    case RESIZE_NONE: new_denom = SCALE_NUMERATOR; break;

    case RESIZE_FIXED:

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

        new_denom = resize_cfg->resize_kf_scale_denominator;

      else

        new_denom = resize_cfg->resize_scale_denominator;

      break;

    case RESIZE_RANDOM: new_denom = lcg_rand16(&seed) % 9 + 8; break;

    default: assert(0);

  }

  return new_denom;

}

int av1_superres_in_recode_allowed(const AV1_COMP *const cpi) {

  const AV1EncoderConfig *const oxcf = &cpi->oxcf;

  // Empirically found to not be beneficial for image coding.

  return oxcf->superres_cfg.superres_mode == AOM_SUPERRES_AUTO &&

         cpi->sf.hl_sf.superres_auto_search_type != SUPERRES_AUTO_SOLO &&

         cpi->rc.frames_to_key > 1;

}

#define SUPERRES_ENERGY_BY_Q2_THRESH_KEYFRAME_SOLO 0.012

#define SUPERRES_ENERGY_BY_Q2_THRESH_KEYFRAME 0.008

#define SUPERRES_ENERGY_BY_Q2_THRESH_ARFFRAME 0.008

#define SUPERRES_ENERGY_BY_AC_THRESH 0.2

static double get_energy_by_q2_thresh(const GF_GROUP *gf_group,

                                      const RATE_CONTROL *rc,

                                      int gf_frame_index) {

  // TODO(now): Return keyframe thresh * factor based on frame type / pyramid

  // level.

  if (gf_group->update_type[gf_frame_index] == ARF_UPDATE) {

    return SUPERRES_ENERGY_BY_Q2_THRESH_ARFFRAME;

  } else if (gf_group->update_type[gf_frame_index] == KF_UPDATE) {

    if (rc->frames_to_key <= 1)

      return SUPERRES_ENERGY_BY_Q2_THRESH_KEYFRAME_SOLO;

    else

      return SUPERRES_ENERGY_BY_Q2_THRESH_KEYFRAME;

  } else {

    assert(0);

  }

  return 0;

}

static uint8_t get_superres_denom_from_qindex_energy(int qindex, double *energy,

                                                     double threshq,

                                                     double threshp) {

  const double q = av1_convert_qindex_to_q(qindex, AOM_BITS_8);

  const double tq = threshq * q * q;

  const double tp = threshp * energy[1];

  const double thresh = AOMMIN(tq, tp);

  int k;

  for (k = SCALE_NUMERATOR * 2; k > SCALE_NUMERATOR; --k) {

    if (energy[k - 1] > thresh) break;

  }

  return 3 * SCALE_NUMERATOR - k;

}

static uint8_t get_superres_denom_for_qindex(const AV1_COMP *cpi, int qindex,

                                             int sr_kf, int sr_arf) {

  // Use superres for Key-frames and Alt-ref frames only.

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

  if (gf_group->update_type[cpi->gf_frame_index] != KF_UPDATE &&

      gf_group->update_type[cpi->gf_frame_index] != ARF_UPDATE) {

    return SCALE_NUMERATOR;

  }

  if (gf_group->update_type[cpi->gf_frame_index] == KF_UPDATE && !sr_kf) {

    return SCALE_NUMERATOR;

  }

  if (gf_group->update_type[cpi->gf_frame_index] == ARF_UPDATE && !sr_arf) {

    return SCALE_NUMERATOR;

  }

  double energy[16];

  analyze_hor_freq(cpi, energy);

  const double energy_by_q2_thresh =

      get_energy_by_q2_thresh(gf_group, &cpi->rc, cpi->gf_frame_index);

  int denom = get_superres_denom_from_qindex_energy(

      qindex, energy, energy_by_q2_thresh, SUPERRES_ENERGY_BY_AC_THRESH);

  /*

  printf("\nenergy = [");

  for (int k = 1; k < 16; ++k) printf("%f, ", energy[k]);

  printf("]\n");

  printf("boost = %d\n",

         (gf_group->update_type[cpi->gf_frame_index] == KF_UPDATE)

             ? cpi->ppi->p_rc.kf_boost

             : cpi->rc.gfu_boost);

  printf("denom = %d\n", denom);

  */

  if (av1_superres_in_recode_allowed(cpi)) {

    assert(cpi->superres_mode != AOM_SUPERRES_NONE);

    // Force superres to be tried in the recode loop, as full-res is also going

    // to be tried anyway.

    denom = AOMMAX(denom, SCALE_NUMERATOR + 1);

  }

  return denom;

}

static uint8_t calculate_next_superres_scale(AV1_COMP *cpi) {

  // Choose an arbitrary random number

  static unsigned int seed = 34567;

  const AV1EncoderConfig *oxcf = &cpi->oxcf;

  const SuperResCfg *const superres_cfg = &oxcf->superres_cfg;

  const FrameDimensionCfg *const frm_dim_cfg = &oxcf->frm_dim_cfg;

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

  if (is_stat_generation_stage(cpi)) return SCALE_NUMERATOR;

  uint8_t new_denom = SCALE_NUMERATOR;

  // Make sure that superres mode of the frame is consistent with the

  // sequence-level flag.

  assert(IMPLIES(superres_cfg->superres_mode != AOM_SUPERRES_NONE,

                 cpi->common.seq_params->enable_superres));

  assert(IMPLIES(!cpi->common.seq_params->enable_superres,

                 superres_cfg->superres_mode == AOM_SUPERRES_NONE));

  // Make sure that superres mode for current encoding is consistent with user

  // provided superres mode.

  assert(IMPLIES(superres_cfg->superres_mode != AOM_SUPERRES_AUTO,

                 cpi->superres_mode == superres_cfg->superres_mode));

  // Note: we must look at the current superres_mode to be tried in 'cpi' here,

  // not the user given mode in 'oxcf'.

  switch (cpi->superres_mode) {

    case AOM_SUPERRES_NONE: new_denom = SCALE_NUMERATOR; break;

    case AOM_SUPERRES_FIXED:

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

        new_denom = superres_cfg->superres_kf_scale_denominator;

      else

        new_denom = superres_cfg->superres_scale_denominator;

      break;

    case AOM_SUPERRES_RANDOM: new_denom = lcg_rand16(&seed) % 9 + 8; break;

    case AOM_SUPERRES_QTHRESH: {

      // Do not use superres when screen content tools are used.

      if (cpi->common.features.allow_screen_content_tools) break;

      if (rc_cfg->mode == AOM_VBR || rc_cfg->mode == AOM_CQ)

        av1_set_target_rate(cpi, frm_dim_cfg->width, frm_dim_cfg->height);

      // Now decide the use of superres based on 'q'.

      int bottom_index, top_index;

      const int q = av1_rc_pick_q_and_bounds(

          cpi, frm_dim_cfg->width, frm_dim_cfg->height, cpi->gf_frame_index,

          &bottom_index, &top_index);

      const int qthresh = (frame_is_intra_only(&cpi->common))

                              ? superres_cfg->superres_kf_qthresh

                              : superres_cfg->superres_qthresh;

      if (q <= qthresh) {

        new_denom = SCALE_NUMERATOR;

      } else {

        new_denom = get_superres_denom_for_qindex(cpi, q, 1, 1);

      }

      break;

    }

    case AOM_SUPERRES_AUTO: {

      if (cpi->common.features.allow_screen_content_tools) break;

      if (rc_cfg->mode == AOM_VBR || rc_cfg->mode == AOM_CQ)

        av1_set_target_rate(cpi, frm_dim_cfg->width, frm_dim_cfg->height);

      // Now decide the use of superres based on 'q'.

      int bottom_index, top_index;

      const int q = av1_rc_pick_q_and_bounds(

          cpi, frm_dim_cfg->width, frm_dim_cfg->height, cpi->gf_frame_index,

          &bottom_index, &top_index);

      const SUPERRES_AUTO_SEARCH_TYPE sr_search_type =

          cpi->sf.hl_sf.superres_auto_search_type;

      const int qthresh = (sr_search_type == SUPERRES_AUTO_SOLO) ? 128 : 0;

      if (q <= qthresh) {

        new_denom = SCALE_NUMERATOR;  // Don't use superres.

      } else {

        if (sr_search_type == SUPERRES_AUTO_ALL) {

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

            new_denom = superres_cfg->superres_kf_scale_denominator;

          else

            new_denom = superres_cfg->superres_scale_denominator;

        } else {

          new_denom = get_superres_denom_for_qindex(cpi, q, 1, 1);

        }

      }

      break;

    }

    default: assert(0);

  }

  return new_denom;

}

static int dimension_is_ok(int orig_dim, int resized_dim, int denom) {

  return (resized_dim * SCALE_NUMERATOR >= orig_dim * denom / 2);

}

static int dimensions_are_ok(int owidth, int oheight, size_params_type *rsz) {

  // Only need to check the width, as scaling is horizontal only.

  (void)oheight;

  return dimension_is_ok(owidth, rsz->resize_width, rsz->superres_denom);

}

static int validate_size_scales(RESIZE_MODE resize_mode,

                                aom_superres_mode superres_mode, int owidth,

                                int oheight, size_params_type *rsz) {

  if (dimensions_are_ok(owidth, oheight, rsz)) {  // Nothing to do.

    return 1;

  }

  // Calculate current resize scale.

  int resize_denom =

      AOMMAX(DIVIDE_AND_ROUND(owidth * SCALE_NUMERATOR, rsz->resize_width),

             DIVIDE_AND_ROUND(oheight * SCALE_NUMERATOR, rsz->resize_height));

  if (resize_mode != RESIZE_RANDOM && superres_mode == AOM_SUPERRES_RANDOM) {

    // Alter superres scale as needed to enforce conformity.

    rsz->superres_denom =

        (2 * SCALE_NUMERATOR * SCALE_NUMERATOR) / resize_denom;

    if (!dimensions_are_ok(owidth, oheight, rsz)) {

      if (rsz->superres_denom > SCALE_NUMERATOR) --rsz->superres_denom;

    }

  } else if (resize_mode == RESIZE_RANDOM &&

             superres_mode != AOM_SUPERRES_RANDOM) {

    // Alter resize scale as needed to enforce conformity.

    resize_denom =

        (2 * SCALE_NUMERATOR * SCALE_NUMERATOR) / rsz->superres_denom;

    rsz->resize_width = owidth;

    rsz->resize_height = oheight;

    av1_calculate_scaled_size(&rsz->resize_width, &rsz->resize_height,

                              resize_denom);

    if (!dimensions_are_ok(owidth, oheight, rsz)) {

      if (resize_denom > SCALE_NUMERATOR) {

        --resize_denom;

        rsz->resize_width = owidth;

        rsz->resize_height = oheight;

        av1_calculate_scaled_size(&rsz->resize_width, &rsz->resize_height,

                                  resize_denom);

      }

    }

  } else if (resize_mode == RESIZE_RANDOM &&

             superres_mode == AOM_SUPERRES_RANDOM) {

    // Alter both resize and superres scales as needed to enforce conformity.

    do {

      if (resize_denom > rsz->superres_denom)

        --resize_denom;

      else

        --rsz->superres_denom;

      rsz->resize_width = owidth;

      rsz->resize_height = oheight;

      av1_calculate_scaled_size(&rsz->resize_width, &rsz->resize_height,

                                resize_denom);

    } while (!dimensions_are_ok(owidth, oheight, rsz) &&

             (resize_denom > SCALE_NUMERATOR ||

              rsz->superres_denom > SCALE_NUMERATOR));

  } else {  // We are allowed to alter neither resize scale nor superres

            // scale.

    return 0;

  }

  return dimensions_are_ok(owidth, oheight, rsz);

}

// Calculates resize and superres params for next frame

static size_params_type calculate_next_size_params(AV1_COMP *cpi) {

  const AV1EncoderConfig *oxcf = &cpi->oxcf;

  ResizePendingParams *resize_pending_params = &cpi->resize_pending_params;

  const FrameDimensionCfg *const frm_dim_cfg = &oxcf->frm_dim_cfg;

  size_params_type rsz = { frm_dim_cfg->width, frm_dim_cfg->height,

                           SCALE_NUMERATOR };

  int resize_denom = SCALE_NUMERATOR;

  if (has_no_stats_stage(cpi) && cpi->ppi->use_svc &&

      (cpi->common.width != cpi->oxcf.frm_dim_cfg.width ||

       cpi->common.height != cpi->oxcf.frm_dim_cfg.height)) {

    rsz.resize_width = cpi->common.width;

    rsz.resize_height = cpi->common.height;

    return rsz;

  }

  if (is_stat_generation_stage(cpi)) return rsz;

  if (resize_pending_params->width && resize_pending_params->height) {

    rsz.resize_width = resize_pending_params->width;

    rsz.resize_height = resize_pending_params->height;

    resize_pending_params->width = resize_pending_params->height = 0;

    if (oxcf->superres_cfg.superres_mode == AOM_SUPERRES_NONE) return rsz;

  } else {

    resize_denom = calculate_next_resize_scale(cpi);

    rsz.resize_width = frm_dim_cfg->width;

    rsz.resize_height = frm_dim_cfg->height;

    av1_calculate_scaled_size(&rsz.resize_width, &rsz.resize_height,

                              resize_denom);

  }

  rsz.superres_denom = calculate_next_superres_scale(cpi);

  if (!validate_size_scales(oxcf->resize_cfg.resize_mode, cpi->superres_mode,

                            frm_dim_cfg->width, frm_dim_cfg->height, &rsz))

    assert(0 && "Invalid scale parameters");

  return rsz;

}

static void setup_frame_size_from_params(AV1_COMP *cpi,

                                         const size_params_type *rsz) {

  int encode_width = rsz->resize_width;

  int encode_height = rsz->resize_height;

  AV1_COMMON *cm = &cpi->common;

  cm->superres_upscaled_width = encode_width;

  cm->superres_upscaled_height = encode_height;

  cm->superres_scale_denominator = rsz->superres_denom;

  av1_calculate_scaled_superres_size(&encode_width, &encode_height,

                                     rsz->superres_denom);

  av1_set_frame_size(cpi, encode_width, encode_height);

}

void av1_setup_frame_size(AV1_COMP *cpi) {

  AV1_COMMON *cm = &cpi->common;

  // Reset superres params from previous frame.

  cm->superres_scale_denominator = SCALE_NUMERATOR;

  const size_params_type rsz = calculate_next_size_params(cpi);

  setup_frame_size_from_params(cpi, &rsz);

  assert(av1_is_min_tile_width_satisfied(cm));

}

void av1_superres_post_encode(AV1_COMP *cpi) {

  AV1_COMMON *cm = &cpi->common;

  assert(cpi->oxcf.superres_cfg.enable_superres);

  assert(!is_lossless_requested(&cpi->oxcf.rc_cfg));

  assert(!cm->features.all_lossless);

  av1_superres_upscale(cm, NULL, cpi->alloc_pyramid);

  // If regular resizing is occurring the source will need to be downscaled to

  // match the upscaled superres resolution. Otherwise the original source is

  // used.

  if (!av1_resize_scaled(cm)) {

    cpi->source = cpi->unscaled_source;

    if (cpi->last_source != NULL) cpi->last_source = cpi->unscaled_last_source;

  } else {

    assert(cpi->unscaled_source->y_crop_width != cm->superres_upscaled_width);

    assert(cpi->unscaled_source->y_crop_height != cm->superres_upscaled_height);

    // Do downscale. cm->(width|height) has been updated by

    // av1_superres_upscale

    cpi->source = realloc_and_scale_source(cpi, cm->superres_upscaled_width,

                                           cm->superres_upscaled_height);

  }

}