text: /*
   *  Copyright (c) 2010 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 <assert.h>
  
  #include "mem.h"
  
  #include "vp9_loopfilter.h"
  #include "vp9_onyxc_int.h"
  #include "vp9_quant_common.h"
  
  #include "vp9_encoder.h"
  #include "vp9_picklpf.h"
  #include "vp9_blockd.h"
  #include "vpx_dsp_common.h"
  
  static int get_max_filter_level(const VP9_COMP *cpi) {
      (void)cpi;
  #if 1 // Hsan: filter_level derivation
      return MAX_LOOP_FILTER;
  #else
    if (cpi->oxcf.pass == 2) {
      return cpi->twopass.section_intra_rating > 8 ? MAX_LOOP_FILTER * 3 / 4
                                                   : MAX_LOOP_FILTER;
    } else {
      return MAX_LOOP_FILTER;
    }
  #endif
  }
  
  void eb_vp9_pick_filter_level(
  #if 0
      const YV12_BUFFER_CONFIG *sd,
  #endif
      VP9_COMP *cpi,
      LPF_PICK_METHOD method) {
  
    VP9_COMMON *const cm = &cpi->common;
    struct loop_filter *const lf = &cm->lf;
  
    lf->sharpness_level = 0;
  
    if (method == LPF_PICK_MINIMAL_LPF && lf->filter_level) {
      lf->filter_level = 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 = eb_vp9_ac_quant(cm->base_qindex, 0, cm->bit_depth);
  // These values were determined by linear fitting the result of the
  // searched level, filt_guess = q * 0.316206 + 3.87252
  #if CONFIG_VP9_HIGHBITDEPTH
      int filt_guess;
      switch (cm->bit_depth) {
        case VPX_BITS_8:
          filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 1015158, 18);
          break;
        case VPX_BITS_10:
          filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 4060632, 20);
          break;
        default:
          assert(cm->bit_depth == VPX_BITS_12);
          filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 16242526, 22);
          break;
      }
  #else
      int filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 1015158, 18);
  #endif  // CONFIG_VP9_HIGHBITDEPTH
  
  #if 0 // Hsan: condition not satisfied for SVT-VP9
      if (cpi->oxcf.pass == 0 && cpi->oxcf.rc_mode == VPX_CBR &&
          cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cm->seg.enabled &&
          cpi->oxcf.content != VP9E_CONTENT_SCREEN && cm->frame_type != KEY_FRAME)
        filt_guess = 5 * filt_guess >> 3;
  #endif
  
      if (cm->frame_type == KEY_FRAME) filt_guess -= 4;
  
      lf->filter_level = clamp(filt_guess, min_filter_level, max_filter_level);
  
    } else {
  #if 1 // Hsan: not supported
        assert(0);
  #else
      lf->filter_level =
          search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE);
  #endif
    }
  
  }
  