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comparison: media/libvpx/vp9/encoder/vp9_subexp.c
media/libvpx/vp9/encoder/vp9_subexp.c
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| 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 | |
| 11 #include "vp9/common/vp9_common.h" | |
| 12 #include "vp9/common/vp9_entropy.h" | |
| 13 | |
| 14 #include "vp9/encoder/vp9_boolhuff.h" | |
| 15 #include "vp9/encoder/vp9_treewriter.h" | |
| 16 | |
| 17 #define vp9_cost_upd ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd)) >> 8) | |
| 18 #define vp9_cost_upd256 ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd))) | |
| 19 | |
| 20 static int update_bits[255]; | |
| 21 | |
| 22 static int count_uniform(int v, int n) { | |
| 23 int l = get_unsigned_bits(n); | |
| 24 int m; | |
| 25 if (l == 0) return 0; | |
| 26 m = (1 << l) - n; | |
| 27 if (v < m) | |
| 28 return l - 1; | |
| 29 else | |
| 30 return l; | |
| 31 } | |
| 32 | |
| 33 static int split_index(int i, int n, int modulus) { | |
| 34 int max1 = (n - 1 - modulus / 2) / modulus + 1; | |
| 35 if (i % modulus == modulus / 2) | |
| 36 i = i / modulus; | |
| 37 else | |
| 38 i = max1 + i - (i + modulus - modulus / 2) / modulus; | |
| 39 return i; | |
| 40 } | |
| 41 | |
| 42 static int recenter_nonneg(int v, int m) { | |
| 43 if (v > (m << 1)) | |
| 44 return v; | |
| 45 else if (v >= m) | |
| 46 return ((v - m) << 1); | |
| 47 else | |
| 48 return ((m - v) << 1) - 1; | |
| 49 } | |
| 50 | |
| 51 static int remap_prob(int v, int m) { | |
| 52 int i; | |
| 53 static const int map_table[MAX_PROB - 1] = { | |
| 54 // generated by: | |
| 55 // map_table[j] = split_index(j, MAX_PROB - 1, MODULUS_PARAM); | |
| 56 20, 21, 22, 23, 24, 25, 0, 26, 27, 28, 29, 30, 31, 32, 33, | |
| 57 34, 35, 36, 37, 1, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, | |
| 58 48, 49, 2, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, | |
| 59 3, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 4, 74, | |
| 60 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 5, 86, 87, 88, | |
| 61 89, 90, 91, 92, 93, 94, 95, 96, 97, 6, 98, 99, 100, 101, 102, | |
| 62 103, 104, 105, 106, 107, 108, 109, 7, 110, 111, 112, 113, 114, 115, 116, | |
| 63 117, 118, 119, 120, 121, 8, 122, 123, 124, 125, 126, 127, 128, 129, 130, | |
| 64 131, 132, 133, 9, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, | |
| 65 145, 10, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 11, | |
| 66 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 12, 170, 171, | |
| 67 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 13, 182, 183, 184, 185, | |
| 68 186, 187, 188, 189, 190, 191, 192, 193, 14, 194, 195, 196, 197, 198, 199, | |
| 69 200, 201, 202, 203, 204, 205, 15, 206, 207, 208, 209, 210, 211, 212, 213, | |
| 70 214, 215, 216, 217, 16, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, | |
| 71 228, 229, 17, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, | |
| 72 18, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 19, | |
| 73 }; | |
| 74 v--; | |
| 75 m--; | |
| 76 if ((m << 1) <= MAX_PROB) | |
| 77 i = recenter_nonneg(v, m) - 1; | |
| 78 else | |
| 79 i = recenter_nonneg(MAX_PROB - 1 - v, MAX_PROB - 1 - m) - 1; | |
| 80 | |
| 81 i = map_table[i]; | |
| 82 return i; | |
| 83 } | |
| 84 | |
| 85 static int count_term_subexp(int word, int k, int num_syms) { | |
| 86 int count = 0; | |
| 87 int i = 0; | |
| 88 int mk = 0; | |
| 89 while (1) { | |
| 90 int b = (i ? k + i - 1 : k); | |
| 91 int a = (1 << b); | |
| 92 if (num_syms <= mk + 3 * a) { | |
| 93 count += count_uniform(word - mk, num_syms - mk); | |
| 94 break; | |
| 95 } else { | |
| 96 int t = (word >= mk + a); | |
| 97 count++; | |
| 98 if (t) { | |
| 99 i = i + 1; | |
| 100 mk += a; | |
| 101 } else { | |
| 102 count += b; | |
| 103 break; | |
| 104 } | |
| 105 } | |
| 106 } | |
| 107 return count; | |
| 108 } | |
| 109 | |
| 110 static int prob_diff_update_cost(vp9_prob newp, vp9_prob oldp) { | |
| 111 int delp = remap_prob(newp, oldp); | |
| 112 return update_bits[delp] * 256; | |
| 113 } | |
| 114 | |
| 115 static void encode_uniform(vp9_writer *w, int v, int n) { | |
| 116 int l = get_unsigned_bits(n); | |
| 117 int m; | |
| 118 if (l == 0) | |
| 119 return; | |
| 120 m = (1 << l) - n; | |
| 121 if (v < m) { | |
| 122 vp9_write_literal(w, v, l - 1); | |
| 123 } else { | |
| 124 vp9_write_literal(w, m + ((v - m) >> 1), l - 1); | |
| 125 vp9_write_literal(w, (v - m) & 1, 1); | |
| 126 } | |
| 127 } | |
| 128 | |
| 129 static void encode_term_subexp(vp9_writer *w, int word, int k, int num_syms) { | |
| 130 int i = 0; | |
| 131 int mk = 0; | |
| 132 while (1) { | |
| 133 int b = (i ? k + i - 1 : k); | |
| 134 int a = (1 << b); | |
| 135 if (num_syms <= mk + 3 * a) { | |
| 136 encode_uniform(w, word - mk, num_syms - mk); | |
| 137 break; | |
| 138 } else { | |
| 139 int t = (word >= mk + a); | |
| 140 vp9_write_literal(w, t, 1); | |
| 141 if (t) { | |
| 142 i = i + 1; | |
| 143 mk += a; | |
| 144 } else { | |
| 145 vp9_write_literal(w, word - mk, b); | |
| 146 break; | |
| 147 } | |
| 148 } | |
| 149 } | |
| 150 } | |
| 151 | |
| 152 void vp9_write_prob_diff_update(vp9_writer *w, vp9_prob newp, vp9_prob oldp) { | |
| 153 const int delp = remap_prob(newp, oldp); | |
| 154 encode_term_subexp(w, delp, SUBEXP_PARAM, 255); | |
| 155 } | |
| 156 | |
| 157 void vp9_compute_update_table() { | |
| 158 int i; | |
| 159 for (i = 0; i < 254; i++) | |
| 160 update_bits[i] = count_term_subexp(i, SUBEXP_PARAM, 255); | |
| 161 } | |
| 162 | |
| 163 int vp9_prob_diff_update_savings_search(const unsigned int *ct, | |
| 164 vp9_prob oldp, vp9_prob *bestp, | |
| 165 vp9_prob upd) { | |
| 166 const int old_b = cost_branch256(ct, oldp); | |
| 167 int bestsavings = 0; | |
| 168 vp9_prob newp, bestnewp = oldp; | |
| 169 const int step = *bestp > oldp ? -1 : 1; | |
| 170 | |
| 171 for (newp = *bestp; newp != oldp; newp += step) { | |
| 172 const int new_b = cost_branch256(ct, newp); | |
| 173 const int update_b = prob_diff_update_cost(newp, oldp) + vp9_cost_upd256; | |
| 174 const int savings = old_b - new_b - update_b; | |
| 175 if (savings > bestsavings) { | |
| 176 bestsavings = savings; | |
| 177 bestnewp = newp; | |
| 178 } | |
| 179 } | |
| 180 *bestp = bestnewp; | |
| 181 return bestsavings; | |
| 182 } | |
| 183 | |
| 184 int vp9_prob_diff_update_savings_search_model(const unsigned int *ct, | |
| 185 const vp9_prob *oldp, | |
| 186 vp9_prob *bestp, | |
| 187 vp9_prob upd, | |
| 188 int b, int r) { | |
| 189 int i, old_b, new_b, update_b, savings, bestsavings, step; | |
| 190 int newp; | |
| 191 vp9_prob bestnewp, newplist[ENTROPY_NODES], oldplist[ENTROPY_NODES]; | |
| 192 vp9_model_to_full_probs(oldp, oldplist); | |
| 193 vpx_memcpy(newplist, oldp, sizeof(vp9_prob) * UNCONSTRAINED_NODES); | |
| 194 for (i = UNCONSTRAINED_NODES, old_b = 0; i < ENTROPY_NODES; ++i) | |
| 195 old_b += cost_branch256(ct + 2 * i, oldplist[i]); | |
| 196 old_b += cost_branch256(ct + 2 * PIVOT_NODE, oldplist[PIVOT_NODE]); | |
| 197 | |
| 198 bestsavings = 0; | |
| 199 bestnewp = oldp[PIVOT_NODE]; | |
| 200 | |
| 201 step = (*bestp > oldp[PIVOT_NODE] ? -1 : 1); | |
| 202 | |
| 203 for (newp = *bestp; newp != oldp[PIVOT_NODE]; newp += step) { | |
| 204 if (newp < 1 || newp > 255) | |
| 205 continue; | |
| 206 newplist[PIVOT_NODE] = newp; | |
| 207 vp9_model_to_full_probs(newplist, newplist); | |
| 208 for (i = UNCONSTRAINED_NODES, new_b = 0; i < ENTROPY_NODES; ++i) | |
| 209 new_b += cost_branch256(ct + 2 * i, newplist[i]); | |
| 210 new_b += cost_branch256(ct + 2 * PIVOT_NODE, newplist[PIVOT_NODE]); | |
| 211 update_b = prob_diff_update_cost(newp, oldp[PIVOT_NODE]) + | |
| 212 vp9_cost_upd256; | |
| 213 savings = old_b - new_b - update_b; | |
| 214 if (savings > bestsavings) { | |
| 215 bestsavings = savings; | |
| 216 bestnewp = newp; | |
| 217 } | |
| 218 } | |
| 219 *bestp = bestnewp; | |
| 220 return bestsavings; | |
| 221 } | |
| 222 | |
| 223 void vp9_cond_prob_diff_update(vp9_writer *w, vp9_prob *oldp, | |
| 224 const unsigned int ct[2]) { | |
| 225 const vp9_prob upd = DIFF_UPDATE_PROB; | |
| 226 vp9_prob newp = get_binary_prob(ct[0], ct[1]); | |
| 227 const int savings = vp9_prob_diff_update_savings_search(ct, *oldp, &newp, | |
| 228 upd); | |
| 229 assert(newp >= 1); | |
| 230 if (savings > 0) { | |
| 231 vp9_write(w, 1, upd); | |
| 232 vp9_write_prob_diff_update(w, newp, *oldp); | |
| 233 *oldp = newp; | |
| 234 } else { | |
| 235 vp9_write(w, 0, upd); | |
| 236 } | |
| 237 } |
