1/* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11#include <assert.h> 12#include <limits.h> 13 14#include "./vpx_scale_rtcd.h" 15 16#include "vpx_mem/vpx_mem.h" 17 18#include "vp9/common/vp9_loopfilter.h" 19#include "vp9/common/vp9_onyxc_int.h" 20#include "vp9/common/vp9_quant_common.h" 21 22#include "vp9/encoder/vp9_onyx_int.h" 23#include "vp9/encoder/vp9_picklpf.h" 24#include "vp9/encoder/vp9_quantize.h" 25 26static int get_max_filter_level(VP9_COMP *cpi) { 27 return cpi->twopass.section_intra_rating > 8 ? MAX_LOOP_FILTER * 3 / 4 28 : MAX_LOOP_FILTER; 29} 30 31 32static int try_filter_frame(const YV12_BUFFER_CONFIG *sd, VP9_COMP *const cpi, 33 int filt_level, int partial_frame) { 34 VP9_COMMON *const cm = &cpi->common; 35 int filt_err; 36 37 vp9_loop_filter_frame(cm, &cpi->mb.e_mbd, filt_level, 1, partial_frame); 38 filt_err = vp9_calc_ss_err(sd, cm->frame_to_show); 39 40 // Re-instate the unfiltered frame 41 vpx_yv12_copy_y(&cpi->last_frame_uf, cm->frame_to_show); 42 43 return filt_err; 44} 45 46static void search_filter_level(const YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi, 47 int partial_frame) { 48 VP9_COMMON *const cm = &cpi->common; 49 struct loopfilter *const lf = &cm->lf; 50 const int min_filter_level = 0; 51 const int max_filter_level = get_max_filter_level(cpi); 52 int best_err; 53 int filt_best; 54 int filt_direction = 0; 55 // Start the search at the previous frame filter level unless it is now out of 56 // range. 57 int filt_mid = clamp(lf->filter_level, min_filter_level, max_filter_level); 58 int filter_step = filt_mid < 16 ? 4 : filt_mid / 4; 59 // Sum squared error at each filter level 60 int ss_err[MAX_LOOP_FILTER + 1]; 61 62 // Set each entry to -1 63 vpx_memset(ss_err, 0xFF, sizeof(ss_err)); 64 65 // Make a copy of the unfiltered / processed recon buffer 66 vpx_yv12_copy_y(cm->frame_to_show, &cpi->last_frame_uf); 67 68 best_err = try_filter_frame(sd, cpi, filt_mid, partial_frame); 69 filt_best = filt_mid; 70 ss_err[filt_mid] = best_err; 71 72 while (filter_step > 0) { 73 const int filt_high = MIN(filt_mid + filter_step, max_filter_level); 74 const int filt_low = MAX(filt_mid - filter_step, min_filter_level); 75 int filt_err; 76 77 // Bias against raising loop filter in favor of lowering it. 78 int bias = (best_err >> (15 - (filt_mid / 8))) * filter_step; 79 80 if (cpi->twopass.section_intra_rating < 20) 81 bias = bias * cpi->twopass.section_intra_rating / 20; 82 83 // yx, bias less for large block size 84 if (cm->tx_mode != ONLY_4X4) 85 bias >>= 1; 86 87 if (filt_direction <= 0 && filt_low != filt_mid) { 88 // Get Low filter error score 89 if (ss_err[filt_low] < 0) { 90 filt_err = try_filter_frame(sd, cpi, filt_low, partial_frame); 91 ss_err[filt_low] = filt_err; 92 } else { 93 filt_err = ss_err[filt_low]; 94 } 95 // If value is close to the best so far then bias towards a lower loop 96 // filter value. 97 if ((filt_err - bias) < best_err) { 98 // Was it actually better than the previous best? 99 if (filt_err < best_err) 100 best_err = filt_err; 101 102 filt_best = filt_low; 103 } 104 } 105 106 // Now look at filt_high 107 if (filt_direction >= 0 && filt_high != filt_mid) { 108 if (ss_err[filt_high] < 0) { 109 filt_err = try_filter_frame(sd, cpi, filt_high, partial_frame); 110 ss_err[filt_high] = filt_err; 111 } else { 112 filt_err = ss_err[filt_high]; 113 } 114 // Was it better than the previous best? 115 if (filt_err < (best_err - bias)) { 116 best_err = filt_err; 117 filt_best = filt_high; 118 } 119 } 120 121 // Half the step distance if the best filter value was the same as last time 122 if (filt_best == filt_mid) { 123 filter_step /= 2; 124 filt_direction = 0; 125 } else { 126 filt_direction = (filt_best < filt_mid) ? -1 : 1; 127 filt_mid = filt_best; 128 } 129 } 130 131 lf->filter_level = filt_best; 132} 133 134void vp9_pick_filter_level(const YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi, 135 LPF_PICK_METHOD method) { 136 VP9_COMMON *const cm = &cpi->common; 137 struct loopfilter *const lf = &cm->lf; 138 139 lf->sharpness_level = cm->frame_type == KEY_FRAME ? 0 140 : cpi->oxcf.sharpness; 141 142 if (method == LPF_PICK_FROM_Q) { 143 const int min_filter_level = 0; 144 const int max_filter_level = get_max_filter_level(cpi); 145 const int q = vp9_ac_quant(cm->base_qindex, 0); 146 // These values were determined by linear fitting the result of the 147 // searched level, filt_guess = q * 0.316206 + 3.87252 148 int filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 1015158, 18); 149 if (cm->frame_type == KEY_FRAME) 150 filt_guess -= 4; 151 lf->filter_level = clamp(filt_guess, min_filter_level, max_filter_level); 152 } else { 153 search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE); 154 } 155} 156