/*

 * Copyright (c) 2016, Alliance for Open Media. All rights reserved.

 *

 * This source code is subject to the terms of the BSD 2 Clause License and

 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License

 * was not distributed with this source code in the LICENSE file, you can

 * obtain it at www.aomedia.org/license/software. If the Alliance for Open

 * Media Patent License 1.0 was not distributed with this source code in the

 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.

 */

#include <assert.h>

#include <limits.h>

#include "config/aom_scale_rtcd.h"

#include "aom_dsp/aom_dsp_common.h"

#include "aom_dsp/psnr.h"

#include "aom_mem/aom_mem.h"

#include "aom_ports/mem.h"

#include "av1/common/av1_common_int.h"

#include "av1/common/av1_loopfilter.h"

#include "av1/common/quant_common.h"

#include "av1/encoder/av1_quantize.h"

#include "av1/encoder/encoder.h"

#include "av1/encoder/picklpf.h"

// AV1 loop filter applies to the whole frame according to mi_rows and mi_cols,

// which are calculated based on aligned width and aligned height,

// In addition, if super res is enabled, it copies the whole frame

// according to the aligned width and height (av1_superres_upscale()).

// So we need to copy the whole filtered region, instead of the cropped region.

// For example, input image size is: 160x90.

// Then src->y_crop_width = 160, src->y_crop_height = 90.

// The aligned frame size is: src->y_width = 160, src->y_height = 96.

// AV1 aligns frame size to a multiple of 8, if there is

// chroma subsampling, it is able to ensure the chroma is also

// an integer number of mi units. mi unit is 4x4, 8 = 4 * 2, and 2 luma mi

// units correspond to 1 chroma mi unit if there is subsampling.

// See: aom_realloc_frame_buffer() in yv12config.c.

static void yv12_copy_plane(const YV12_BUFFER_CONFIG *src_bc,

                            YV12_BUFFER_CONFIG *dst_bc, int plane) {

  switch (plane) {

    case 0: aom_yv12_copy_y(src_bc, dst_bc, 0); break;

    case 1: aom_yv12_copy_u(src_bc, dst_bc, 0); break;

    case 2: aom_yv12_copy_v(src_bc, dst_bc, 0); break;

    default: assert(plane >= 0 && plane <= 2); break;

  }

}

static int get_max_filter_level(const AV1_COMP *cpi) {

  if (is_stat_consumption_stage_twopass(cpi)) {

    return cpi->ppi->twopass.section_intra_rating > 8 ? MAX_LOOP_FILTER * 3 / 4

                                                      : MAX_LOOP_FILTER;

  } else {

    return MAX_LOOP_FILTER;

  }

}

static int64_t try_filter_frame(const YV12_BUFFER_CONFIG *sd,

                                AV1_COMP *const cpi, int filt_level,

                                int partial_frame, int plane, int dir) {

  MultiThreadInfo *const mt_info = &cpi->mt_info;

  int num_workers = mt_info->num_mod_workers[MOD_LPF];

  AV1_COMMON *const cm = &cpi->common;

  int64_t filt_err;

  assert(plane >= 0 && plane <= 2);

  int filter_level[2] = { filt_level, filt_level };

  if (plane == 0 && dir == 0) filter_level[1] = cm->lf.filter_level[1];

  if (plane == 0 && dir == 1) filter_level[0] = cm->lf.filter_level[0];

  // set base filters for use of get_filter_level (av1_loopfilter.c) when in

  // DELTA_LF mode

  switch (plane) {

    case 0:

      cm->lf.filter_level[0] = filter_level[0];

      cm->lf.filter_level[1] = filter_level[1];

      break;

    case 1: cm->lf.filter_level_u = filter_level[0]; break;

    case 2: cm->lf.filter_level_v = filter_level[0]; break;

  }

  // lpf_opt_level = 1 : Enables dual/quad loop-filtering.

  int lpf_opt_level = is_inter_tx_size_search_level_one(&cpi->sf.tx_sf);

  av1_loop_filter_frame_mt(&cm->cur_frame->buf, cm, &cpi->td.mb.e_mbd, plane,

                           plane + 1, partial_frame, mt_info->workers,

                           num_workers, &mt_info->lf_row_sync, lpf_opt_level);

  filt_err = aom_get_sse_plane(sd, &cm->cur_frame->buf, plane,

                               cm->seq_params->use_highbitdepth);

  // Re-instate the unfiltered frame

  yv12_copy_plane(&cpi->last_frame_uf, &cm->cur_frame->buf, plane);

  return filt_err;

}

static int search_filter_level(const YV12_BUFFER_CONFIG *sd, AV1_COMP *cpi,

                               int partial_frame,

                               const int *last_frame_filter_level, int plane,

                               int dir, int64_t *best_filter_sse) {

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

  const int min_filter_level = 0;

  const int max_filter_level = get_max_filter_level(cpi);

  int filt_direction = 0;

  int64_t best_err;

  int filt_best;

  // Start the search at the previous frame filter level unless it is now out of

  // range.

  int lvl;

  switch (plane) {

    case 0:

      switch (dir) {

        case 2:

          lvl = (last_frame_filter_level[0] + last_frame_filter_level[1] + 1) >>

                1;

          break;

        case 0:

        case 1: lvl = last_frame_filter_level[dir]; break;

        default: assert(dir >= 0 && dir <= 2); return 0;

      }

      break;

    case 1: lvl = last_frame_filter_level[2]; break;

    case 2: lvl = last_frame_filter_level[3]; break;

    default: assert(plane >= 0 && plane <= 2); return 0;

  }

  int filt_mid = clamp(lvl, min_filter_level, max_filter_level);

  int filter_step = filt_mid < 16 ? 4 : filt_mid / 4;

  // Sum squared error at each filter level

  int64_t ss_err[MAX_LOOP_FILTER + 1];

  const int use_coarse_search = cpi->sf.lpf_sf.use_coarse_filter_level_search;

  assert(use_coarse_search <= 1);

  static const int min_filter_step_lookup[2] = { 0, 2 };

  // min_filter_step_thesh determines the stopping criteria for the search.

  // The search is terminated when filter_step equals min_filter_step_thesh.

  const int min_filter_step_thesh = min_filter_step_lookup[use_coarse_search];

  // Set each entry to -1

  memset(ss_err, 0xFF, sizeof(ss_err));

  yv12_copy_plane(&cm->cur_frame->buf, &cpi->last_frame_uf, plane);

  best_err = try_filter_frame(sd, cpi, filt_mid, partial_frame, plane, dir);

  filt_best = filt_mid;

  ss_err[filt_mid] = best_err;

  while (filter_step > min_filter_step_thesh) {

    const int filt_high = AOMMIN(filt_mid + filter_step, max_filter_level);

    const int filt_low = AOMMAX(filt_mid - filter_step, min_filter_level);

    // Bias against raising loop filter in favor of lowering it.

    int64_t bias = (best_err >> (15 - (filt_mid / 8))) * filter_step;

    if ((is_stat_consumption_stage_twopass(cpi)) &&

        (cpi->ppi->twopass.section_intra_rating < 20))

      bias = (bias * cpi->ppi->twopass.section_intra_rating) / 20;

    // yx, bias less for large block size

    if (cm->features.tx_mode != ONLY_4X4) bias >>= 1;

    if (filt_direction <= 0 && filt_low != filt_mid) {

      // Get Low filter error score

      if (ss_err[filt_low] < 0) {

        ss_err[filt_low] =

            try_filter_frame(sd, cpi, filt_low, partial_frame, plane, dir);

      }

      // If value is close to the best so far then bias towards a lower loop

      // filter value.

      if (ss_err[filt_low] < (best_err + bias)) {

        // Was it actually better than the previous best?

        if (ss_err[filt_low] < best_err) {

          best_err = ss_err[filt_low];

        }

        filt_best = filt_low;

      }

    }

    // Now look at filt_high

    if (filt_direction >= 0 && filt_high != filt_mid) {

      if (ss_err[filt_high] < 0) {

        ss_err[filt_high] =

            try_filter_frame(sd, cpi, filt_high, partial_frame, plane, dir);

      }

      // If value is significantly better than previous best, bias added against

      // raising filter value

      if (ss_err[filt_high] < (best_err - bias)) {

        best_err = ss_err[filt_high];

        filt_best = filt_high;

      }

    }

    // Half the step distance if the best filter value was the same as last time

    if (filt_best == filt_mid) {

      filter_step /= 2;

      filt_direction = 0;

    } else {

      filt_direction = (filt_best < filt_mid) ? -1 : 1;

      filt_mid = filt_best;

    }

  }

  *best_filter_sse = ss_err[filt_best];

  return filt_best;

}

void av1_pick_filter_level(const YV12_BUFFER_CONFIG *sd, AV1_COMP *cpi,

                           LPF_PICK_METHOD method) {

  AV1_COMMON *const cm = &cpi->common;

  const SequenceHeader *const seq_params = cm->seq_params;

  const int num_planes = av1_num_planes(cm);

  struct loopfilter *const lf = &cm->lf;

  int disable_filter_rt_screen = 0;

  (void)sd;

  // Enable loop filter sharpness only for allintra encoding mode,

  // as frames do not have to serve as references to others

  lf->sharpness_level =

      cpi->oxcf.mode == ALLINTRA ? cpi->oxcf.algo_cfg.sharpness : 0;

  if (cpi->oxcf.algo_cfg.enable_adaptive_sharpness) {

    // Loop filter sharpness levels are highly nonlinear. Visually, lf sharpness

    // 1 is closer to 7 than it is to 0, so in practice adaptive sharpness is

    // written to pick levels 0, 1 and 7 to keep it simple.

    int max_lf_sharpness;

    if (cm->quant_params.base_qindex <= 120) {

      max_lf_sharpness = 7;

    } else if (cm->quant_params.base_qindex <= 160) {

      max_lf_sharpness = 1;

    } else {

      max_lf_sharpness = 0;

    }

    lf->sharpness_level = AOMMIN(lf->sharpness_level, max_lf_sharpness);

  }

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

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

      cpi->sf.rt_sf.skip_lf_screen)

    disable_filter_rt_screen = av1_cyclic_refresh_disable_lf_cdef(cpi);

  if (disable_filter_rt_screen ||

      cpi->oxcf.algo_cfg.loopfilter_control == LOOPFILTER_NONE ||

      (cpi->oxcf.algo_cfg.loopfilter_control == LOOPFILTER_REFERENCE &&

       cpi->ppi->rtc_ref.non_reference_frame)) {

    lf->filter_level[0] = 0;

    lf->filter_level[1] = 0;

    return;

  }

  if (method == LPF_PICK_MINIMAL_LPF) {

    lf->filter_level[0] = 0;

    lf->filter_level[1] = 0;

  } else if (method >= LPF_PICK_FROM_Q) {

    const int min_filter_level = 0;

    const int max_filter_level = get_max_filter_level(cpi);

    const int q = av1_ac_quant_QTX(cm->quant_params.base_qindex, 0,

                                   seq_params->bit_depth);

    // based on tests result for rtc test set

    // 0.04590 boosted or 0.02295 non-booseted in 18-bit fixed point

    const int strength_boost_q_treshold = 0;

    int inter_frame_multiplier =

        (q > strength_boost_q_treshold ||

         (cpi->sf.rt_sf.use_nonrd_pick_mode &&

          cpi->common.width * cpi->common.height > 352 * 288))

            ? 12034

            : 6017;

    // Increase strength on base TL0 for temporal layers, for low-resoln,

    // based on frame source_sad.

    if (cpi->svc.number_temporal_layers > 1 &&

        cpi->svc.temporal_layer_id == 0 &&

        cpi->common.width * cpi->common.height <= 352 * 288 &&

        cpi->sf.rt_sf.use_nonrd_pick_mode) {

      if (cpi->rc.frame_source_sad > 100000)

        inter_frame_multiplier = inter_frame_multiplier << 1;

      else if (cpi->rc.frame_source_sad > 50000)

        inter_frame_multiplier = 3 * (inter_frame_multiplier >> 1);

    } else if (cpi->sf.rt_sf.use_fast_fixed_part) {

      inter_frame_multiplier = inter_frame_multiplier << 1;

    }

    // These values were determined by linear fitting the result of the

    // searched level for 8 bit depth:

    // Keyframes: filt_guess = q * 0.06699 - 1.60817

    // Other frames: filt_guess = q * inter_frame_multiplier + 2.48225

    //

    // And high bit depth separately:

    // filt_guess = q * 0.316206 + 3.87252

    int filt_guess;

    switch (seq_params->bit_depth) {

      case AOM_BITS_8:

        filt_guess =

            (cm->current_frame.frame_type == KEY_FRAME)

                ? ROUND_POWER_OF_TWO(q * 17563 - 421574, 18)

                : ROUND_POWER_OF_TWO(q * inter_frame_multiplier + 650707, 18);

        break;

      case AOM_BITS_10:

        filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 4060632, 20);

        break;

      case AOM_BITS_12:

        filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 16242526, 22);

        break;

      default:

        assert(0 &&

               "bit_depth should be AOM_BITS_8, AOM_BITS_10 "

               "or AOM_BITS_12");

        return;

    }

    if (seq_params->bit_depth != AOM_BITS_8 &&

        cm->current_frame.frame_type == KEY_FRAME)

      filt_guess -= 4;

    // TODO(chengchen): retrain the model for Y, U, V filter levels

    lf->filter_level[0] = clamp(filt_guess, min_filter_level, max_filter_level);

    lf->filter_level[1] = clamp(filt_guess, min_filter_level, max_filter_level);

    lf->filter_level_u = clamp(filt_guess, min_filter_level, max_filter_level);

    lf->filter_level_v = clamp(filt_guess, min_filter_level, max_filter_level);

    if (cpi->oxcf.algo_cfg.loopfilter_control == LOOPFILTER_SELECTIVELY &&

        !frame_is_intra_only(cm) && !cpi->rc.high_source_sad) {

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

        lf->filter_level[0] = 0;

        lf->filter_level[1] = 0;

      } else {

        const int num4x4 = (cm->width >> 2) * (cm->height >> 2);

        const int newmv_thresh = 7;

        const int distance_since_key_thresh = 5;

        if ((cpi->td.rd_counts.newmv_or_intra_blocks * 100 / num4x4) <

                newmv_thresh &&

            cpi->rc.frames_since_key > distance_since_key_thresh) {

          lf->filter_level[0] = 0;

          lf->filter_level[1] = 0;

        }

      }

    }

  } else {

    int last_frame_filter_level[4] = { 0 };

    if (!frame_is_intra_only(cm)) {

      last_frame_filter_level[0] = cpi->ppi->filter_level[0];

      last_frame_filter_level[1] = cpi->ppi->filter_level[1];

      last_frame_filter_level[2] = cpi->ppi->filter_level_u;

      last_frame_filter_level[3] = cpi->ppi->filter_level_v;

    }

    // The frame buffer last_frame_uf is used to store the non-loop filtered

    // reconstructed frame in search_filter_level().

    if (aom_realloc_frame_buffer(

            &cpi->last_frame_uf, cm->width, cm->height,

            seq_params->subsampling_x, seq_params->subsampling_y,

            seq_params->use_highbitdepth, cpi->oxcf.border_in_pixels,

            cm->features.byte_alignment, NULL, NULL, NULL, false, 0))

      aom_internal_error(cm->error, AOM_CODEC_MEM_ERROR,

                         "Failed to allocate last frame buffer");

    int64_t zero_filter_sse[MAX_MB_PLANE] = { 0 };

    int64_t best_filter_sse[MAX_MB_PLANE] = { 0 };

    if (cpi->sf.lpf_sf.skip_loop_filter_using_filt_error >= 1) {

      for (int plane = 0; plane < num_planes; plane++) {

        zero_filter_sse[plane] = aom_get_sse_plane(

            sd, &cm->cur_frame->buf, plane, cm->seq_params->use_highbitdepth);

      }

    }

    lf->filter_level[0] = lf->filter_level[1] =

        search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,

                            last_frame_filter_level, 0, 2, &best_filter_sse[0]);

    if (method != LPF_PICK_FROM_FULL_IMAGE_NON_DUAL) {

      lf->filter_level[0] = search_filter_level(

          sd, cpi, method == LPF_PICK_FROM_SUBIMAGE, last_frame_filter_level, 0,

          0, &best_filter_sse[0]);

      lf->filter_level[1] = search_filter_level(

          sd, cpi, method == LPF_PICK_FROM_SUBIMAGE, last_frame_filter_level, 0,

          1, &best_filter_sse[0]);

    }

    if (num_planes > 1) {

      lf->filter_level_u = search_filter_level(

          sd, cpi, method == LPF_PICK_FROM_SUBIMAGE, last_frame_filter_level, 1,

          0, &best_filter_sse[1]);

      lf->filter_level_v = search_filter_level(

          sd, cpi, method == LPF_PICK_FROM_SUBIMAGE, last_frame_filter_level, 2,

          0, &best_filter_sse[2]);

    }

    lf->backup_filter_level[0] = lf->filter_level[0];

    lf->backup_filter_level[1] = lf->filter_level[1];

    lf->backup_filter_level_u = lf->filter_level_u;

    lf->backup_filter_level_v = lf->filter_level_v;

    if (cpi->sf.lpf_sf.adaptive_luma_loop_filter_skip >= 1) {

      int32_t min_ref_filter_level[2] = { MAX_LOOP_FILTER, MAX_LOOP_FILTER };

      // Find the minimum luma filter levels across all reference frames.

      for (int ref = LAST_FRAME; ref <= ALTREF_FRAME; ++ref) {

        const RefCntBuffer *const buf = get_ref_frame_buf(cm, ref);

        if (buf == NULL) continue;

        if (buf->filter_level[0] != -1)

          min_ref_filter_level[0] =

              AOMMIN(min_ref_filter_level[0], buf->filter_level[0]);

        if (buf->filter_level[1] != -1)

          min_ref_filter_level[1] =

              AOMMIN(min_ref_filter_level[1], buf->filter_level[1]);

      }

      // Reset luma filter levels to zero based on minimum filter levels of

      // reference frames and current frame's pyramid level.

      unsigned int pyramid_level = cm->current_frame.pyramid_level;

      if (pyramid_level > 1) {

        int filter_threshold;

        if (pyramid_level >= 5)

          filter_threshold = 32;

        else if (pyramid_level >= 4)

          filter_threshold = 16;

        else

          filter_threshold = 8;

        const bool reset_filter_level_y =

            lf->filter_level[0] < filter_threshold &&

            lf->filter_level[1] < filter_threshold &&

            lf->filter_level_u < filter_threshold &&

            lf->filter_level_v < filter_threshold &&

            min_ref_filter_level[0] == 0 && min_ref_filter_level[1] == 0;

        if (reset_filter_level_y) {

          lf->filter_level[0] = 0;

          lf->filter_level[1] = 0;

        }

      }

    }

    if (lf->filter_level[0] != 0 && lf->filter_level[1] != 0 &&

        cpi->sf.lpf_sf.skip_loop_filter_using_filt_error >= 1) {

      const double pct_improvement_thresh = 2.0;

      bool reset_filter_level_y = true;

      // Calculate the percentage improvement in SSE for each plane. This

      // measures the relative reduction in error when applying the filter

      // compared to no filtering.

      for (int plane = 0; plane < num_planes; plane++) {

        const double pct_improvement_sse =

            ((zero_filter_sse[plane] - best_filter_sse[plane]) * 100.0) /

            zero_filter_sse[plane];

        reset_filter_level_y &= pct_improvement_sse < pct_improvement_thresh;

      }

      if (reset_filter_level_y) {

        lf->filter_level[0] = 0;

        lf->filter_level[1] = 0;

      }

    }

    // Store the current frame's filter levels to be referenced

    // while determining the minimum filter level from reference frames.

    cm->cur_frame->filter_level[0] = lf->filter_level[0];

    cm->cur_frame->filter_level[1] = lf->filter_level[1];

  }

}