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 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 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. 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
