2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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.
14 #include "./vpx_scale_rtcd.h"
16 #include "vpx_mem/vpx_mem.h"
18 #include "vp9/common/vp9_loopfilter.h"
19 #include "vp9/common/vp9_onyxc_int.h"
20 #include "vp9/common/vp9_quant_common.h"
22 #include "vp9/encoder/vp9_encoder.h"
23 #include "vp9/encoder/vp9_picklpf.h"
24 #include "vp9/encoder/vp9_quantize.h"
26 static int get_max_filter_level(const VP9_COMP *cpi) {
27 if (cpi->oxcf.pass == 2) {
28 return cpi->twopass.section_intra_rating > 8 ? MAX_LOOP_FILTER * 3 / 4
31 return MAX_LOOP_FILTER;
36 static int try_filter_frame(const YV12_BUFFER_CONFIG *sd, VP9_COMP *const cpi,
37 int filt_level, int partial_frame) {
38 VP9_COMMON *const cm = &cpi->common;
41 vp9_loop_filter_frame(cm->frame_to_show, cm, &cpi->mb.e_mbd, filt_level, 1,
43 #if CONFIG_VP9_HIGHBITDEPTH
44 if (cm->use_highbitdepth) {
45 filt_err = vp9_highbd_get_y_sse(sd, cm->frame_to_show, cm->bit_depth);
47 filt_err = vp9_get_y_sse(sd, cm->frame_to_show);
50 filt_err = vp9_get_y_sse(sd, cm->frame_to_show);
51 #endif // CONFIG_VP9_HIGHBITDEPTH
53 // Re-instate the unfiltered frame
54 vpx_yv12_copy_y(&cpi->last_frame_uf, cm->frame_to_show);
59 static int search_filter_level(const YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi,
61 const VP9_COMMON *const cm = &cpi->common;
62 const struct loopfilter *const lf = &cm->lf;
63 const int min_filter_level = 0;
64 const int max_filter_level = get_max_filter_level(cpi);
65 int filt_direction = 0;
66 int best_err, filt_best;
68 // Start the search at the previous frame filter level unless it is now out of
70 int filt_mid = clamp(lf->filter_level, min_filter_level, max_filter_level);
71 int filter_step = filt_mid < 16 ? 4 : filt_mid / 4;
72 // Sum squared error at each filter level
73 int ss_err[MAX_LOOP_FILTER + 1];
75 // Set each entry to -1
76 vpx_memset(ss_err, 0xFF, sizeof(ss_err));
78 // Make a copy of the unfiltered / processed recon buffer
79 vpx_yv12_copy_y(cm->frame_to_show, &cpi->last_frame_uf);
81 best_err = try_filter_frame(sd, cpi, filt_mid, partial_frame);
83 ss_err[filt_mid] = best_err;
85 while (filter_step > 0) {
86 const int filt_high = MIN(filt_mid + filter_step, max_filter_level);
87 const int filt_low = MAX(filt_mid - filter_step, min_filter_level);
89 // Bias against raising loop filter in favor of lowering it.
90 int bias = (best_err >> (15 - (filt_mid / 8))) * filter_step;
92 if ((cpi->oxcf.pass == 2) && (cpi->twopass.section_intra_rating < 20))
93 bias = (bias * cpi->twopass.section_intra_rating) / 20;
95 // yx, bias less for large block size
96 if (cm->tx_mode != ONLY_4X4)
99 if (filt_direction <= 0 && filt_low != filt_mid) {
100 // Get Low filter error score
101 if (ss_err[filt_low] < 0) {
102 ss_err[filt_low] = try_filter_frame(sd, cpi, filt_low, partial_frame);
104 // If value is close to the best so far then bias towards a lower loop
106 if ((ss_err[filt_low] - bias) < best_err) {
107 // Was it actually better than the previous best?
108 if (ss_err[filt_low] < best_err)
109 best_err = ss_err[filt_low];
111 filt_best = filt_low;
115 // Now look at filt_high
116 if (filt_direction >= 0 && filt_high != filt_mid) {
117 if (ss_err[filt_high] < 0) {
118 ss_err[filt_high] = try_filter_frame(sd, cpi, filt_high, partial_frame);
120 // Was it better than the previous best?
121 if (ss_err[filt_high] < (best_err - bias)) {
122 best_err = ss_err[filt_high];
123 filt_best = filt_high;
127 // Half the step distance if the best filter value was the same as last time
128 if (filt_best == filt_mid) {
132 filt_direction = (filt_best < filt_mid) ? -1 : 1;
133 filt_mid = filt_best;
140 void vp9_pick_filter_level(const YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi,
141 LPF_PICK_METHOD method) {
142 VP9_COMMON *const cm = &cpi->common;
143 struct loopfilter *const lf = &cm->lf;
145 lf->sharpness_level = cm->frame_type == KEY_FRAME ? 0
146 : cpi->oxcf.sharpness;
148 if (method == LPF_PICK_MINIMAL_LPF && lf->filter_level) {
149 lf->filter_level = 0;
150 } else if (method >= LPF_PICK_FROM_Q) {
151 const int min_filter_level = 0;
152 const int max_filter_level = get_max_filter_level(cpi);
153 const int q = vp9_ac_quant(cm->base_qindex, 0, cm->bit_depth);
154 // These values were determined by linear fitting the result of the
155 // searched level, filt_guess = q * 0.316206 + 3.87252
156 #if CONFIG_VP9_HIGHDEPTH
158 switch (cm->bit_depth) {
160 filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 1015158, 18);
163 filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 4060632, 20);
166 filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 16242526, 22);
169 assert(0 && "bit_depth should be VPX_BITS_8, VPX_BITS_10 "
174 int filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 1015158, 18);
175 #endif // CONFIG_VP9_HIGHBITDEPTH
176 if (cm->frame_type == KEY_FRAME)
178 lf->filter_level = clamp(filt_guess, min_filter_level, max_filter_level);
180 lf->filter_level = search_filter_level(sd, cpi,
181 method == LPF_PICK_FROM_SUBIMAGE);