ref: cdf1077d5ac268ad52d4512bd992e1a23b229d7b
dir: /vp10/encoder/subexp.c/
/* * 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 "vpx_dsp/bitwriter.h" #include "vp10/common/common.h" #include "vp10/common/entropy.h" #include "vp10/encoder/cost.h" #include "vp10/encoder/subexp.h" #define vp10_cost_upd256 ((int)(vp10_cost_one(upd) - vp10_cost_zero(upd))) static const uint8_t update_bits[255] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11 - CONFIG_MISC_FIXES, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 0, }; 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 uint8_t 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 prob_diff_update_cost(vpx_prob newp, vpx_prob oldp) { int delp = remap_prob(newp, oldp); return update_bits[delp] * 256; } static void encode_uniform(vpx_writer *w, int v) { const int l = 8; const int m = (1 << l) - 191 + CONFIG_MISC_FIXES; if (v < m) { vpx_write_literal(w, v, l - 1); } else { vpx_write_literal(w, m + ((v - m) >> 1), l - 1); vpx_write_literal(w, (v - m) & 1, 1); } } static INLINE int write_bit_gte(vpx_writer *w, int word, int test) { vpx_write_literal(w, word >= test, 1); return word >= test; } static void encode_term_subexp(vpx_writer *w, int word) { if (!write_bit_gte(w, word, 16)) { vpx_write_literal(w, word, 4); } else if (!write_bit_gte(w, word, 32)) { vpx_write_literal(w, word - 16, 4); } else if (!write_bit_gte(w, word, 64)) { vpx_write_literal(w, word - 32, 5); } else { encode_uniform(w, word - 64); } } void vp10_write_prob_diff_update(vpx_writer *w, vpx_prob newp, vpx_prob oldp) { const int delp = remap_prob(newp, oldp); encode_term_subexp(w, delp); } int vp10_prob_diff_update_savings_search(const unsigned int *ct, vpx_prob oldp, vpx_prob *bestp, vpx_prob upd) { const int old_b = cost_branch256(ct, oldp); int bestsavings = 0; vpx_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) + vp10_cost_upd256; const int savings = old_b - new_b - update_b; if (savings > bestsavings) { bestsavings = savings; bestnewp = newp; } } *bestp = bestnewp; return bestsavings; } int vp10_prob_diff_update_savings_search_model(const unsigned int *ct, const vpx_prob *oldp, vpx_prob *bestp, vpx_prob upd, int stepsize) { int i, old_b, new_b, update_b, savings, bestsavings; int newp; const int step_sign = *bestp > oldp[PIVOT_NODE] ? -1 : 1; const int step = stepsize * step_sign; vpx_prob bestnewp, newplist[ENTROPY_NODES], oldplist[ENTROPY_NODES]; vp10_model_to_full_probs(oldp, oldplist); memcpy(newplist, oldp, sizeof(vpx_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]; assert(stepsize > 0); for (newp = *bestp; (newp - oldp[PIVOT_NODE]) * step_sign < 0; newp += step) { if (newp < 1 || newp > 255) continue; newplist[PIVOT_NODE] = newp; vp10_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]) + vp10_cost_upd256; savings = old_b - new_b - update_b; if (savings > bestsavings) { bestsavings = savings; bestnewp = newp; } } *bestp = bestnewp; return bestsavings; } void vp10_cond_prob_diff_update(vpx_writer *w, vpx_prob *oldp, const unsigned int ct[2]) { const vpx_prob upd = DIFF_UPDATE_PROB; vpx_prob newp = get_binary_prob(ct[0], ct[1]); const int savings = vp10_prob_diff_update_savings_search(ct, *oldp, &newp, upd); assert(newp >= 1); if (savings > 0) { vpx_write(w, 1, upd); vp10_write_prob_diff_update(w, newp, *oldp); *oldp = newp; } else { vpx_write(w, 0, upd); } } int vp10_cond_prob_diff_update_savings(vpx_prob *oldp, const unsigned int ct[2]) { const vpx_prob upd = DIFF_UPDATE_PROB; vpx_prob newp = get_binary_prob(ct[0], ct[1]); const int savings = vp10_prob_diff_update_savings_search(ct, *oldp, &newp, upd); return savings; }