| /* |
| * Copyright (c) 2013 The WebM project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| #include "vp9/common/vp9_common.h" |
| #include "vp9/common/vp9_entropy.h" |
| |
| #include "vp9/encoder/vp9_boolhuff.h" |
| #include "vp9/encoder/vp9_treewriter.h" |
| |
| #define vp9_cost_upd ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd)) >> 8) |
| #define vp9_cost_upd256 ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd))) |
| |
| static int update_bits[255]; |
| |
| static int count_uniform(int v, int n) { |
| int l = get_unsigned_bits(n); |
| int m; |
| if (l == 0) return 0; |
| m = (1 << l) - n; |
| if (v < m) |
| return l - 1; |
| else |
| return l; |
| } |
| |
| static int split_index(int i, int n, int modulus) { |
| int max1 = (n - 1 - modulus / 2) / modulus + 1; |
| if (i % modulus == modulus / 2) |
| i = i / modulus; |
| else |
| i = max1 + i - (i + modulus - modulus / 2) / modulus; |
| return i; |
| } |
| |
| static int recenter_nonneg(int v, int m) { |
| if (v > (m << 1)) |
| return v; |
| else if (v >= m) |
| return ((v - m) << 1); |
| else |
| return ((m - v) << 1) - 1; |
| } |
| |
| static int remap_prob(int v, int m) { |
| int i; |
| static const int map_table[MAX_PROB - 1] = { |
| // generated by: |
| // map_table[j] = split_index(j, MAX_PROB - 1, MODULUS_PARAM); |
| 20, 21, 22, 23, 24, 25, 0, 26, 27, 28, 29, 30, 31, 32, 33, |
| 34, 35, 36, 37, 1, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, |
| 48, 49, 2, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, |
| 3, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 4, 74, |
| 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 5, 86, 87, 88, |
| 89, 90, 91, 92, 93, 94, 95, 96, 97, 6, 98, 99, 100, 101, 102, |
| 103, 104, 105, 106, 107, 108, 109, 7, 110, 111, 112, 113, 114, 115, 116, |
| 117, 118, 119, 120, 121, 8, 122, 123, 124, 125, 126, 127, 128, 129, 130, |
| 131, 132, 133, 9, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, |
| 145, 10, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 11, |
| 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 12, 170, 171, |
| 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 13, 182, 183, 184, 185, |
| 186, 187, 188, 189, 190, 191, 192, 193, 14, 194, 195, 196, 197, 198, 199, |
| 200, 201, 202, 203, 204, 205, 15, 206, 207, 208, 209, 210, 211, 212, 213, |
| 214, 215, 216, 217, 16, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, |
| 228, 229, 17, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, |
| 18, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 19, |
| }; |
| v--; |
| m--; |
| if ((m << 1) <= MAX_PROB) |
| i = recenter_nonneg(v, m) - 1; |
| else |
| i = recenter_nonneg(MAX_PROB - 1 - v, MAX_PROB - 1 - m) - 1; |
| |
| i = map_table[i]; |
| return i; |
| } |
| |
| static int count_term_subexp(int word, int k, int num_syms) { |
| int count = 0; |
| int i = 0; |
| int mk = 0; |
| while (1) { |
| int b = (i ? k + i - 1 : k); |
| int a = (1 << b); |
| if (num_syms <= mk + 3 * a) { |
| count += count_uniform(word - mk, num_syms - mk); |
| break; |
| } else { |
| int t = (word >= mk + a); |
| count++; |
| if (t) { |
| i = i + 1; |
| mk += a; |
| } else { |
| count += b; |
| break; |
| } |
| } |
| } |
| return count; |
| } |
| |
| static int prob_diff_update_cost(vp9_prob newp, vp9_prob oldp) { |
| int delp = remap_prob(newp, oldp); |
| return update_bits[delp] * 256; |
| } |
| |
| static void encode_uniform(vp9_writer *w, int v, int n) { |
| int l = get_unsigned_bits(n); |
| int m; |
| if (l == 0) |
| return; |
| m = (1 << l) - n; |
| if (v < m) { |
| vp9_write_literal(w, v, l - 1); |
| } else { |
| vp9_write_literal(w, m + ((v - m) >> 1), l - 1); |
| vp9_write_literal(w, (v - m) & 1, 1); |
| } |
| } |
| |
| static void encode_term_subexp(vp9_writer *w, int word, int k, int num_syms) { |
| int i = 0; |
| int mk = 0; |
| while (1) { |
| int b = (i ? k + i - 1 : k); |
| int a = (1 << b); |
| if (num_syms <= mk + 3 * a) { |
| encode_uniform(w, word - mk, num_syms - mk); |
| break; |
| } else { |
| int t = (word >= mk + a); |
| vp9_write_literal(w, t, 1); |
| if (t) { |
| i = i + 1; |
| mk += a; |
| } else { |
| vp9_write_literal(w, word - mk, b); |
| break; |
| } |
| } |
| } |
| } |
| |
| void vp9_write_prob_diff_update(vp9_writer *w, vp9_prob newp, vp9_prob oldp) { |
| const int delp = remap_prob(newp, oldp); |
| encode_term_subexp(w, delp, SUBEXP_PARAM, 255); |
| } |
| |
| void vp9_compute_update_table() { |
| int i; |
| for (i = 0; i < 254; i++) |
| update_bits[i] = count_term_subexp(i, SUBEXP_PARAM, 255); |
| } |
| |
| int vp9_prob_diff_update_savings_search(const unsigned int *ct, |
| vp9_prob oldp, vp9_prob *bestp, |
| vp9_prob upd) { |
| const int old_b = cost_branch256(ct, oldp); |
| int bestsavings = 0; |
| vp9_prob newp, bestnewp = oldp; |
| const int step = *bestp > oldp ? -1 : 1; |
| |
| for (newp = *bestp; newp != oldp; newp += step) { |
| const int new_b = cost_branch256(ct, newp); |
| const int update_b = prob_diff_update_cost(newp, oldp) + vp9_cost_upd256; |
| const int savings = old_b - new_b - update_b; |
| if (savings > bestsavings) { |
| bestsavings = savings; |
| bestnewp = newp; |
| } |
| } |
| *bestp = bestnewp; |
| return bestsavings; |
| } |
| |
| int vp9_prob_diff_update_savings_search_model(const unsigned int *ct, |
| const vp9_prob *oldp, |
| vp9_prob *bestp, |
| vp9_prob upd, |
| int b, int r) { |
| int i, old_b, new_b, update_b, savings, bestsavings, step; |
| int newp; |
| vp9_prob bestnewp, newplist[ENTROPY_NODES], oldplist[ENTROPY_NODES]; |
| vp9_model_to_full_probs(oldp, oldplist); |
| vpx_memcpy(newplist, oldp, sizeof(vp9_prob) * UNCONSTRAINED_NODES); |
| for (i = UNCONSTRAINED_NODES, old_b = 0; i < ENTROPY_NODES; ++i) |
| old_b += cost_branch256(ct + 2 * i, oldplist[i]); |
| old_b += cost_branch256(ct + 2 * PIVOT_NODE, oldplist[PIVOT_NODE]); |
| |
| bestsavings = 0; |
| bestnewp = oldp[PIVOT_NODE]; |
| |
| step = (*bestp > oldp[PIVOT_NODE] ? -1 : 1); |
| |
| for (newp = *bestp; newp != oldp[PIVOT_NODE]; newp += step) { |
| if (newp < 1 || newp > 255) |
| continue; |
| newplist[PIVOT_NODE] = newp; |
| vp9_model_to_full_probs(newplist, newplist); |
| for (i = UNCONSTRAINED_NODES, new_b = 0; i < ENTROPY_NODES; ++i) |
| new_b += cost_branch256(ct + 2 * i, newplist[i]); |
| new_b += cost_branch256(ct + 2 * PIVOT_NODE, newplist[PIVOT_NODE]); |
| update_b = prob_diff_update_cost(newp, oldp[PIVOT_NODE]) + |
| vp9_cost_upd256; |
| savings = old_b - new_b - update_b; |
| if (savings > bestsavings) { |
| bestsavings = savings; |
| bestnewp = newp; |
| } |
| } |
| *bestp = bestnewp; |
| return bestsavings; |
| } |
| |
| void vp9_cond_prob_diff_update(vp9_writer *w, vp9_prob *oldp, |
| const unsigned int ct[2]) { |
| const vp9_prob upd = DIFF_UPDATE_PROB; |
| vp9_prob newp = get_binary_prob(ct[0], ct[1]); |
| const int savings = vp9_prob_diff_update_savings_search(ct, *oldp, &newp, |
| upd); |
| assert(newp >= 1); |
| if (savings > 0) { |
| vp9_write(w, 1, upd); |
| vp9_write_prob_diff_update(w, newp, *oldp); |
| *oldp = newp; |
| } else { |
| vp9_write(w, 0, upd); |
| } |
| } |
