1/* 2 * Copyright (c) 2013 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#include "vpx_dsp/bitwriter.h" 11 12#include "vp9/common/vp9_common.h" 13#include "vp9/common/vp9_entropy.h" 14#include "vp9/encoder/vp9_cost.h" 15#include "vp9/encoder/vp9_subexp.h" 16 17#define vp9_cost_upd256 ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd))) 18 19static const int update_bits[255] = { 20 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 21 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 22 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 23 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 24 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 25 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 26 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 27 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 28 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 29 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 30 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 31 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 32 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 33 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 34 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 35 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 0, 36}; 37 38static int recenter_nonneg(int v, int m) { 39 if (v > (m << 1)) 40 return v; 41 else if (v >= m) 42 return ((v - m) << 1); 43 else 44 return ((m - v) << 1) - 1; 45} 46 47static int remap_prob(int v, int m) { 48 int i; 49 static const int map_table[MAX_PROB - 1] = { 50 // generated by: 51 // map_table[j] = split_index(j, MAX_PROB - 1, MODULUS_PARAM); 52 20, 21, 22, 23, 24, 25, 0, 26, 27, 28, 29, 30, 31, 32, 33, 53 34, 35, 36, 37, 1, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 54 48, 49, 2, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 55 3, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 4, 74, 56 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 5, 86, 87, 88, 57 89, 90, 91, 92, 93, 94, 95, 96, 97, 6, 98, 99, 100, 101, 102, 58 103, 104, 105, 106, 107, 108, 109, 7, 110, 111, 112, 113, 114, 115, 116, 59 117, 118, 119, 120, 121, 8, 122, 123, 124, 125, 126, 127, 128, 129, 130, 60 131, 132, 133, 9, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 61 145, 10, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 11, 62 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 12, 170, 171, 63 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 13, 182, 183, 184, 185, 64 186, 187, 188, 189, 190, 191, 192, 193, 14, 194, 195, 196, 197, 198, 199, 65 200, 201, 202, 203, 204, 205, 15, 206, 207, 208, 209, 210, 211, 212, 213, 66 214, 215, 216, 217, 16, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 67 228, 229, 17, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 68 18, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 19, 69 }; 70 v--; 71 m--; 72 if ((m << 1) <= MAX_PROB) 73 i = recenter_nonneg(v, m) - 1; 74 else 75 i = recenter_nonneg(MAX_PROB - 1 - v, MAX_PROB - 1 - m) - 1; 76 77 i = map_table[i]; 78 return i; 79} 80 81static int prob_diff_update_cost(vpx_prob newp, vpx_prob oldp) { 82 int delp = remap_prob(newp, oldp); 83 return update_bits[delp] * 256; 84} 85 86static void encode_uniform(vpx_writer *w, int v) { 87 const int l = 8; 88 const int m = (1 << l) - 191; 89 if (v < m) { 90 vpx_write_literal(w, v, l - 1); 91 } else { 92 vpx_write_literal(w, m + ((v - m) >> 1), l - 1); 93 vpx_write_literal(w, (v - m) & 1, 1); 94 } 95} 96 97static INLINE int write_bit_gte(vpx_writer *w, int word, int test) { 98 vpx_write_literal(w, word >= test, 1); 99 return word >= test; 100} 101 102static void encode_term_subexp(vpx_writer *w, int word) { 103 if (!write_bit_gte(w, word, 16)) { 104 vpx_write_literal(w, word, 4); 105 } else if (!write_bit_gte(w, word, 32)) { 106 vpx_write_literal(w, word - 16, 4); 107 } else if (!write_bit_gte(w, word, 64)) { 108 vpx_write_literal(w, word - 32, 5); 109 } else { 110 encode_uniform(w, word - 64); 111 } 112} 113 114void vp9_write_prob_diff_update(vpx_writer *w, vpx_prob newp, vpx_prob oldp) { 115 const int delp = remap_prob(newp, oldp); 116 encode_term_subexp(w, delp); 117} 118 119int vp9_prob_diff_update_savings_search(const unsigned int *ct, 120 vpx_prob oldp, vpx_prob *bestp, 121 vpx_prob upd) { 122 const int old_b = cost_branch256(ct, oldp); 123 int bestsavings = 0; 124 vpx_prob newp, bestnewp = oldp; 125 const int step = *bestp > oldp ? -1 : 1; 126 127 for (newp = *bestp; newp != oldp; newp += step) { 128 const int new_b = cost_branch256(ct, newp); 129 const int update_b = prob_diff_update_cost(newp, oldp) + vp9_cost_upd256; 130 const int savings = old_b - new_b - update_b; 131 if (savings > bestsavings) { 132 bestsavings = savings; 133 bestnewp = newp; 134 } 135 } 136 *bestp = bestnewp; 137 return bestsavings; 138} 139 140int vp9_prob_diff_update_savings_search_model(const unsigned int *ct, 141 const vpx_prob *oldp, 142 vpx_prob *bestp, 143 vpx_prob upd, 144 int stepsize) { 145 int i, old_b, new_b, update_b, savings, bestsavings, step; 146 int newp; 147 vpx_prob bestnewp, newplist[ENTROPY_NODES], oldplist[ENTROPY_NODES]; 148 vp9_model_to_full_probs(oldp, oldplist); 149 memcpy(newplist, oldp, sizeof(vpx_prob) * UNCONSTRAINED_NODES); 150 for (i = UNCONSTRAINED_NODES, old_b = 0; i < ENTROPY_NODES; ++i) 151 old_b += cost_branch256(ct + 2 * i, oldplist[i]); 152 old_b += cost_branch256(ct + 2 * PIVOT_NODE, oldplist[PIVOT_NODE]); 153 154 bestsavings = 0; 155 bestnewp = oldp[PIVOT_NODE]; 156 157 if (*bestp > oldp[PIVOT_NODE]) { 158 step = -stepsize; 159 for (newp = *bestp; newp > oldp[PIVOT_NODE]; newp += step) { 160 if (newp < 1 || newp > 255) 161 continue; 162 newplist[PIVOT_NODE] = newp; 163 vp9_model_to_full_probs(newplist, newplist); 164 for (i = UNCONSTRAINED_NODES, new_b = 0; i < ENTROPY_NODES; ++i) 165 new_b += cost_branch256(ct + 2 * i, newplist[i]); 166 new_b += cost_branch256(ct + 2 * PIVOT_NODE, newplist[PIVOT_NODE]); 167 update_b = prob_diff_update_cost(newp, oldp[PIVOT_NODE]) + 168 vp9_cost_upd256; 169 savings = old_b - new_b - update_b; 170 if (savings > bestsavings) { 171 bestsavings = savings; 172 bestnewp = newp; 173 } 174 } 175 } else { 176 step = stepsize; 177 for (newp = *bestp; newp < oldp[PIVOT_NODE]; newp += step) { 178 if (newp < 1 || newp > 255) 179 continue; 180 newplist[PIVOT_NODE] = newp; 181 vp9_model_to_full_probs(newplist, newplist); 182 for (i = UNCONSTRAINED_NODES, new_b = 0; i < ENTROPY_NODES; ++i) 183 new_b += cost_branch256(ct + 2 * i, newplist[i]); 184 new_b += cost_branch256(ct + 2 * PIVOT_NODE, newplist[PIVOT_NODE]); 185 update_b = prob_diff_update_cost(newp, oldp[PIVOT_NODE]) + 186 vp9_cost_upd256; 187 savings = old_b - new_b - update_b; 188 if (savings > bestsavings) { 189 bestsavings = savings; 190 bestnewp = newp; 191 } 192 } 193 } 194 195 *bestp = bestnewp; 196 return bestsavings; 197} 198 199void vp9_cond_prob_diff_update(vpx_writer *w, vpx_prob *oldp, 200 const unsigned int ct[2]) { 201 const vpx_prob upd = DIFF_UPDATE_PROB; 202 vpx_prob newp = get_binary_prob(ct[0], ct[1]); 203 const int savings = vp9_prob_diff_update_savings_search(ct, *oldp, &newp, 204 upd); 205 assert(newp >= 1); 206 if (savings > 0) { 207 vpx_write(w, 1, upd); 208 vp9_write_prob_diff_update(w, newp, *oldp); 209 *oldp = newp; 210 } else { 211 vpx_write(w, 0, upd); 212 } 213} 214