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_dsp/vpx_dsp_common.h"
14 #include "vpx_ports/system_state.h"
15
16 #include "vp9/encoder/vp9_aq_complexity.h"
17 #include "vp9/encoder/vp9_aq_variance.h"
18 #include "vp9/encoder/vp9_encodeframe.h"
19 #include "vp9/common/vp9_seg_common.h"
20 #include "vp9/encoder/vp9_segmentation.h"
21
22 #define AQ_C_SEGMENTS 5
23 #define DEFAULT_AQ2_SEG 3 // Neutral Q segment
24 #define AQ_C_STRENGTHS 3
25 static const double aq_c_q_adj_factor[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
26 { {1.75, 1.25, 1.05, 1.00, 0.90},
27 {2.00, 1.50, 1.15, 1.00, 0.85},
28 {2.50, 1.75, 1.25, 1.00, 0.80} };
29 static const double aq_c_transitions[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
30 { {0.15, 0.30, 0.55, 2.00, 100.0},
31 {0.20, 0.40, 0.65, 2.00, 100.0},
32 {0.25, 0.50, 0.75, 2.00, 100.0} };
33 static const double aq_c_var_thresholds[AQ_C_STRENGTHS][AQ_C_SEGMENTS] =
34 { {-4.0, -3.0, -2.0, 100.00, 100.0},
35 {-3.5, -2.5, -1.5, 100.00, 100.0},
36 {-3.0, -2.0, -1.0, 100.00, 100.0} };
37
38 #define DEFAULT_COMPLEXITY 64
39
40
get_aq_c_strength(int q_index,vpx_bit_depth_t bit_depth)41 static int get_aq_c_strength(int q_index, vpx_bit_depth_t bit_depth) {
42 // Approximate base quatizer (truncated to int)
43 const int base_quant = vp9_ac_quant(q_index, 0, bit_depth) / 4;
44 return (base_quant > 10) + (base_quant > 25);
45 }
46
vp9_setup_in_frame_q_adj(VP9_COMP * cpi)47 void vp9_setup_in_frame_q_adj(VP9_COMP *cpi) {
48 VP9_COMMON *const cm = &cpi->common;
49 struct segmentation *const seg = &cm->seg;
50
51 // Make SURE use of floating point in this function is safe.
52 vpx_clear_system_state();
53
54 if (cm->frame_type == KEY_FRAME ||
55 cpi->refresh_alt_ref_frame ||
56 (cpi->refresh_golden_frame && !cpi->rc.is_src_frame_alt_ref)) {
57 int segment;
58 const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);
59
60 // Clear down the segment map.
61 memset(cpi->segmentation_map, DEFAULT_AQ2_SEG, cm->mi_rows * cm->mi_cols);
62
63 vp9_clearall_segfeatures(seg);
64
65 // Segmentation only makes sense if the target bits per SB is above a
66 // threshold. Below this the overheads will usually outweigh any benefit.
67 if (cpi->rc.sb64_target_rate < 256) {
68 vp9_disable_segmentation(seg);
69 return;
70 }
71
72 vp9_enable_segmentation(seg);
73
74 // Select delta coding method.
75 seg->abs_delta = SEGMENT_DELTADATA;
76
77 // Default segment "Q" feature is disabled so it defaults to the baseline Q.
78 vp9_disable_segfeature(seg, DEFAULT_AQ2_SEG, SEG_LVL_ALT_Q);
79
80 // Use some of the segments for in frame Q adjustment.
81 for (segment = 0; segment < AQ_C_SEGMENTS; ++segment) {
82 int qindex_delta;
83
84 if (segment == DEFAULT_AQ2_SEG)
85 continue;
86
87 qindex_delta =
88 vp9_compute_qdelta_by_rate(&cpi->rc, cm->frame_type, cm->base_qindex,
89 aq_c_q_adj_factor[aq_strength][segment],
90 cm->bit_depth);
91
92
93 // For AQ complexity mode, we dont allow Q0 in a segment if the base
94 // Q is not 0. Q0 (lossless) implies 4x4 only and in AQ mode 2 a segment
95 // Q delta is sometimes applied without going back around the rd loop.
96 // This could lead to an illegal combination of partition size and q.
97 if ((cm->base_qindex != 0) && ((cm->base_qindex + qindex_delta) == 0)) {
98 qindex_delta = -cm->base_qindex + 1;
99 }
100 if ((cm->base_qindex + qindex_delta) > 0) {
101 vp9_enable_segfeature(seg, segment, SEG_LVL_ALT_Q);
102 vp9_set_segdata(seg, segment, SEG_LVL_ALT_Q, qindex_delta);
103 }
104 }
105 }
106 }
107
108 #define DEFAULT_LV_THRESH 10.0
109 #define MIN_DEFAULT_LV_THRESH 8.0
110 #define VAR_STRENGTH_STEP 0.25
111 // Select a segment for the current block.
112 // The choice of segment for a block depends on the ratio of the projected
113 // 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)114 void vp9_caq_select_segment(VP9_COMP *cpi, MACROBLOCK *mb, BLOCK_SIZE bs,
115 int mi_row, int mi_col, int projected_rate) {
116 VP9_COMMON *const cm = &cpi->common;
117
118 const int mi_offset = mi_row * cm->mi_cols + mi_col;
119 const int bw = num_8x8_blocks_wide_lookup[BLOCK_64X64];
120 const int bh = num_8x8_blocks_high_lookup[BLOCK_64X64];
121 const int xmis = VPXMIN(cm->mi_cols - mi_col, num_8x8_blocks_wide_lookup[bs]);
122 const int ymis = VPXMIN(cm->mi_rows - mi_row, num_8x8_blocks_high_lookup[bs]);
123 int x, y;
124 int i;
125 unsigned char segment;
126
127 if (0) {
128 segment = DEFAULT_AQ2_SEG;
129 } else {
130 // Rate depends on fraction of a SB64 in frame (xmis * ymis / bw * bh).
131 // It is converted to bits * 256 units.
132 const int target_rate = (cpi->rc.sb64_target_rate * xmis * ymis * 256) /
133 (bw * bh);
134 double logvar;
135 double low_var_thresh;
136 const int aq_strength = get_aq_c_strength(cm->base_qindex, cm->bit_depth);
137
138 vpx_clear_system_state();
139 low_var_thresh = (cpi->oxcf.pass == 2)
140 ? VPXMAX(cpi->twopass.mb_av_energy, MIN_DEFAULT_LV_THRESH)
141 : DEFAULT_LV_THRESH;
142
143 vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);
144 logvar = vp9_log_block_var(cpi, mb, bs);
145
146 segment = AQ_C_SEGMENTS - 1; // Just in case no break out below.
147 for (i = 0; i < AQ_C_SEGMENTS; ++i) {
148 // Test rate against a threshold value and variance against a threshold.
149 // Increasing segment number (higher variance and complexity) = higher Q.
150 if ((projected_rate <
151 target_rate * aq_c_transitions[aq_strength][i]) &&
152 (logvar < (low_var_thresh + aq_c_var_thresholds[aq_strength][i]))) {
153 segment = i;
154 break;
155 }
156 }
157 }
158
159 // Fill in the entires in the segment map corresponding to this SB64.
160 for (y = 0; y < ymis; y++) {
161 for (x = 0; x < xmis; x++) {
162 cpi->segmentation_map[mi_offset + y * cm->mi_cols + x] = segment;
163 }
164 }
165 }
166