/*

 *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.

 *

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

 */

#include <limits.h>

#include <math.h>

#include "vpx_dsp/vpx_dsp_common.h"

#include "vpx_ports/system_state.h"

#include "vp9/encoder/vp9_aq_complexity.h"

#include "vp9/encoder/vp9_aq_variance.h"

#include "vp9/encoder/vp9_encodeframe.h"

#include "vp9/common/vp9_seg_common.h"

#include "vp9/encoder/vp9_segmentation.h"

#define AQ_C_SEGMENTS 5

#define DEFAULT_AQ2_SEG 3  // Neutral Q segment

#define AQ_C_STRENGTHS 3

static const double aq_c_q_adj_factor[AQ_C_STRENGTHS][AQ_C_SEGMENTS] = {

  { 1.75, 1.25, 1.05, 1.00, 0.90 },

  { 2.00, 1.50, 1.15, 1.00, 0.85 },

  { 2.50, 1.75, 1.25, 1.00, 0.80 }

};

static const double aq_c_transitions[AQ_C_STRENGTHS][AQ_C_SEGMENTS] = {

  { 0.15, 0.30, 0.55, 2.00, 100.0 },

  { 0.20, 0.40, 0.65, 2.00, 100.0 },

  { 0.25, 0.50, 0.75, 2.00, 100.0 }

};

static const double aq_c_var_thresholds[AQ_C_STRENGTHS][AQ_C_SEGMENTS] = {

  { -4.0, -3.0, -2.0, 100.00, 100.0 },

  { -3.5, -2.5, -1.5, 100.00, 100.0 },

  { -3.0, -2.0, -1.0, 100.00, 100.0 }

};

static int get_aq_c_strength(int q_index, vpx_bit_depth_t bit_depth) {

  // Approximate base quatizer (truncated to int)

  const int base_quant = vp9_ac_quant(q_index, 0, bit_depth) / 4;

  return (base_quant > 10) + (base_quant > 25);

}

void vp9_setup_in_frame_q_adj(VP9_COMP *cpi) {

  VP9_COMMON *const cm = &cpi->common;

  struct segmentation *const seg = &cm->seg;

  // Make SURE use of floating point in this function is safe.

  vpx_clear_system_state();

  if (frame_is_intra_only(cm) || cm->error_resilient_mode ||

      cpi->refresh_alt_ref_frame || cpi->force_update_segmentation ||

      (cpi->refresh_golden_frame && !cpi->rc.is_src_frame_alt_ref)) {

    int segment;

    const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);

    // Clear down the segment map.

    memset(cpi->segmentation_map, DEFAULT_AQ2_SEG, cm->mi_rows * cm->mi_cols);

    vp9_clearall_segfeatures(seg);

    // Segmentation only makes sense if the target bits per SB is above a

    // threshold. Below this the overheads will usually outweigh any benefit.

    if (cpi->rc.sb64_target_rate < 256) {

      vp9_disable_segmentation(seg);

      return;

    }

    vp9_enable_segmentation(seg);

    // Select delta coding method.

    seg->abs_delta = SEGMENT_DELTADATA;

    // Default segment "Q" feature is disabled so it defaults to the baseline Q.

    vp9_disable_segfeature(seg, DEFAULT_AQ2_SEG, SEG_LVL_ALT_Q);

    // Use some of the segments for in frame Q adjustment.

    for (segment = 0; segment < AQ_C_SEGMENTS; ++segment) {

      int qindex_delta;

      if (segment == DEFAULT_AQ2_SEG) continue;

      qindex_delta = vp9_compute_qdelta_by_rate(

          &cpi->rc, cm->frame_type, cm->base_qindex,

          aq_c_q_adj_factor[aq_strength][segment], cm->bit_depth);

      // For AQ complexity mode, we don't allow Q0 in a segment if the base

      // Q is not 0. Q0 (lossless) implies 4x4 only and in AQ mode 2 a segment

      // Q delta is sometimes applied without going back around the rd loop.

      // This could lead to an illegal combination of partition size and q.

      if ((cm->base_qindex != 0) && ((cm->base_qindex + qindex_delta) == 0)) {

        qindex_delta = -cm->base_qindex + 1;

      }

      if ((cm->base_qindex + qindex_delta) > 0) {

        vp9_enable_segfeature(seg, segment, SEG_LVL_ALT_Q);

        vp9_set_segdata(seg, segment, SEG_LVL_ALT_Q, qindex_delta);

      }

    }

  }

}

#define DEFAULT_LV_THRESH 10.0

#define MIN_DEFAULT_LV_THRESH 8.0

// Select a segment for the current block.

// The choice of segment for a block depends on the ratio of the projected

// bits for the block vs a target average and its spatial complexity.

void vp9_caq_select_segment(VP9_COMP *cpi, MACROBLOCK *mb, BLOCK_SIZE bs,

                            int mi_row, int mi_col, int projected_rate) {

  VP9_COMMON *const cm = &cpi->common;

  const int mi_offset = mi_row * cm->mi_cols + mi_col;

  const int bw = num_8x8_blocks_wide_lookup[BLOCK_64X64];

  const int bh = num_8x8_blocks_high_lookup[BLOCK_64X64];

  const int xmis = VPXMIN(cm->mi_cols - mi_col, num_8x8_blocks_wide_lookup[bs]);

  const int ymis = VPXMIN(cm->mi_rows - mi_row, num_8x8_blocks_high_lookup[bs]);

  int x, y;

  int i;

  unsigned char segment;

  if (0) {

    segment = DEFAULT_AQ2_SEG;

  } else {

    // Rate depends on fraction of a SB64 in frame (xmis * ymis / bw * bh).

    // It is converted to bits * 256 units.

    const int target_rate =

        (cpi->rc.sb64_target_rate * xmis * ymis * 256) / (bw * bh);

    double logvar;

    double low_var_thresh;

    const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);

    vpx_clear_system_state();

    low_var_thresh = (cpi->oxcf.pass == 2) ? VPXMAX(cpi->twopass.mb_av_energy,

                                                    MIN_DEFAULT_LV_THRESH)

                                           : DEFAULT_LV_THRESH;

    vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);

    logvar = vp9_log_block_var(cpi, mb, bs);

    segment = AQ_C_SEGMENTS - 1;  // Just in case no break out below.

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

      // Test rate against a threshold value and variance against a threshold.

      // Increasing segment number (higher variance and complexity) = higher Q.

      if ((projected_rate < target_rate * aq_c_transitions[aq_strength][i]) &&

          (logvar < (low_var_thresh + aq_c_var_thresholds[aq_strength][i]))) {

        segment = i;

        break;

      }

    }

  }

  // Fill in the entires in the segment map corresponding to this SB64.

  for (y = 0; y < ymis; y++) {

    for (x = 0; x < xmis; x++) {

      cpi->segmentation_map[mi_offset + y * cm->mi_cols + x] = segment;

    }

  }

}