1 /*
2 * Copyright (c) 2014 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 <limits.h>
12 #include <math.h>
13 #include "vpx_ports/system_state.h"
14
15 #include "vp9/encoder/vp9_aq_complexity.h"
16 #include "vp9/encoder/vp9_aq_variance.h"
17 #include "vp9/encoder/vp9_encodeframe.h"
18 #include "vp9/common/vp9_seg_common.h"
19 #include "vp9/encoder/vp9_segmentation.h"
20
21 #define AQ_C_SEGMENTS 5
22 #define DEFAULT_AQ2_SEG 3 // Neutral Q segment
23 #define AQ_C_STRENGTHS 3
24 static const double aq_c_q_adj_factor[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
25 { {1.75, 1.25, 1.05, 1.00, 0.90},
26 {2.00, 1.50, 1.15, 1.00, 0.85},
27 {2.50, 1.75, 1.25, 1.00, 0.80} };
28 static const double aq_c_transitions[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
29 { {0.15, 0.30, 0.55, 2.00, 100.0},
30 {0.20, 0.40, 0.65, 2.00, 100.0},
31 {0.25, 0.50, 0.75, 2.00, 100.0} };
32 static const double aq_c_var_thresholds[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
33 { {-4.0, -3.0, -2.0, 100.00, 100.0},
34 {-3.5, -2.5, -1.5, 100.00, 100.0},
35 {-3.0, -2.0, -1.0, 100.00, 100.0} };
36
37 #define DEFAULT_COMPLEXITY 64
38
39
get_aq_c_strength(int q_index,vpx_bit_depth_t bit_depth)40 static int get_aq_c_strength(int q_index, vpx_bit_depth_t bit_depth) {
41 // Approximate base quatizer (truncated to int)
42 const int base_quant = vp9_ac_quant(q_index, 0, bit_depth) / 4;
43 return (base_quant > 10) + (base_quant > 25);
44 }
45
vp9_setup_in_frame_q_adj(VP9_COMP * cpi)46 void vp9_setup_in_frame_q_adj(VP9_COMP *cpi) {
47 VP9_COMMON *const cm = &cpi->common;
48 struct segmentation *const seg = &cm->seg;
49
50 // Make SURE use of floating point in this function is safe.
51 vpx_clear_system_state();
52
53 if (cm->frame_type == KEY_FRAME ||
54 cpi->refresh_alt_ref_frame ||
55 (cpi->refresh_golden_frame && !cpi->rc.is_src_frame_alt_ref)) {
56 int segment;
57 const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);
58
59 // Clear down the segment map.
60 memset(cpi->segmentation_map, DEFAULT_AQ2_SEG, cm->mi_rows * cm->mi_cols);
61
62 vp9_clearall_segfeatures(seg);
63
64 // Segmentation only makes sense if the target bits per SB is above a
65 // threshold. Below this the overheads will usually outweigh any benefit.
66 if (cpi->rc.sb64_target_rate < 256) {
67 vp9_disable_segmentation(seg);
68 return;
69 }
70
71 vp9_enable_segmentation(seg);
72
73 // Select delta coding method.
74 seg->abs_delta = SEGMENT_DELTADATA;
75
76 // Default segment "Q" feature is disabled so it defaults to the baseline Q.
77 vp9_disable_segfeature(seg, DEFAULT_AQ2_SEG, SEG_LVL_ALT_Q);
78
79 // Use some of the segments for in frame Q adjustment.
80 for (segment = 0; segment < AQ_C_SEGMENTS; ++segment) {
81 int qindex_delta;
82
83 if (segment == DEFAULT_AQ2_SEG)
84 continue;
85
86 qindex_delta =
87 vp9_compute_qdelta_by_rate(&cpi->rc, cm->frame_type, cm->base_qindex,
88 aq_c_q_adj_factor[aq_strength][segment],
89 cm->bit_depth);
90
91
92 // For AQ complexity mode, we dont allow Q0 in a segment if the base
93 // Q is not 0. Q0 (lossless) implies 4x4 only and in AQ mode 2 a segment
94 // Q delta is sometimes applied without going back around the rd loop.
95 // This could lead to an illegal combination of partition size and q.
96 if ((cm->base_qindex != 0) && ((cm->base_qindex + qindex_delta) == 0)) {
97 qindex_delta = -cm->base_qindex + 1;
98 }
99 if ((cm->base_qindex + qindex_delta) > 0) {
100 vp9_enable_segfeature(seg, segment, SEG_LVL_ALT_Q);
101 vp9_set_segdata(seg, segment, SEG_LVL_ALT_Q, qindex_delta);
102 }
103 }
104 }
105 }
106
107 #define DEFAULT_LV_THRESH 10.0
108 #define MIN_DEFAULT_LV_THRESH 8.0
109 #define VAR_STRENGTH_STEP 0.25
110 // Select a segment for the current block.
111 // The choice of segment for a block depends on the ratio of the projected
112 // bits for the block vs a target average and its spatial complexity.
vp9_caq_select_segment(VP9_COMP * cpi,MACROBLOCK * mb,BLOCK_SIZE bs,int mi_row,int mi_col,int projected_rate)113 void vp9_caq_select_segment(VP9_COMP *cpi, MACROBLOCK *mb, BLOCK_SIZE bs,
114 int mi_row, int mi_col, int projected_rate) {
115 VP9_COMMON *const cm = &cpi->common;
116
117 const int mi_offset = mi_row * cm->mi_cols + mi_col;
118 const int bw = num_8x8_blocks_wide_lookup[BLOCK_64X64];
119 const int bh = num_8x8_blocks_high_lookup[BLOCK_64X64];
120 const int xmis = MIN(cm->mi_cols - mi_col, num_8x8_blocks_wide_lookup[bs]);
121 const int ymis = MIN(cm->mi_rows - mi_row, num_8x8_blocks_high_lookup[bs]);
122 int x, y;
123 int i;
124 unsigned char segment;
125
126 if (0) {
127 segment = DEFAULT_AQ2_SEG;
128 } else {
129 // Rate depends on fraction of a SB64 in frame (xmis * ymis / bw * bh).
130 // It is converted to bits * 256 units.
131 const int target_rate = (cpi->rc.sb64_target_rate * xmis * ymis * 256) /
132 (bw * bh);
133 double logvar;
134 double low_var_thresh;
135 const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);
136
137 vpx_clear_system_state();
138 low_var_thresh = (cpi->oxcf.pass == 2)
139 ? MAX(cpi->twopass.mb_av_energy, MIN_DEFAULT_LV_THRESH)
140 : DEFAULT_LV_THRESH;
141
142 vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);
143 logvar = vp9_log_block_var(cpi, mb, bs);
144
145 segment = AQ_C_SEGMENTS - 1; // Just in case no break out below.
146 for (i = 0; i < AQ_C_SEGMENTS; ++i) {
147 // Test rate against a threshold value and variance against a threshold.
148 // Increasing segment number (higher variance and complexity) = higher Q.
149 if ((projected_rate <
150 target_rate * aq_c_transitions[aq_strength][i]) &&
151 (logvar < (low_var_thresh + aq_c_var_thresholds[aq_strength][i]))) {
152 segment = i;
153 break;
154 }
155 }
156 }
157
158 // Fill in the entires in the segment map corresponding to this SB64.
159 for (y = 0; y < ymis; y++) {
160 for (x = 0; x < xmis; x++) {
161 cpi->segmentation_map[mi_offset + y * cm->mi_cols + x] = segment;
162 }
163 }
164 }
165