ref: cffef113b95cb0ff0a2e18cca0ab2b0e77f96020
dir: /vp9/encoder/vp9_cost.c/
/*
* Copyright (c) 2014 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 <assert.h>
#include "vp9/encoder/vp9_cost.h"
/* round(-log2(i/256.) * (1 << VP9_PROB_COST_SHIFT))
Begins and ends with a bogus entry to satisfy use of prob=0 in the firstpass.
https://code.google.com/p/webm/issues/detail?id=1089 */
const uint16_t vp9_prob_cost[257] = {
4096, 4096, 3584, 3284, 3072, 2907, 2772, 2659, 2560, 2473, 2395, 2325,
2260, 2201, 2147, 2096, 2048, 2003, 1961, 1921, 1883, 1847, 1813, 1780,
1748, 1718, 1689, 1661, 1635, 1609, 1584, 1559, 1536, 1513, 1491, 1470,
1449, 1429, 1409, 1390, 1371, 1353, 1335, 1318, 1301, 1284, 1268, 1252,
1236, 1221, 1206, 1192, 1177, 1163, 1149, 1136, 1123, 1110, 1097, 1084,
1072, 1059, 1047, 1036, 1024, 1013, 1001, 990, 979, 968, 958, 947,
937, 927, 917, 907, 897, 887, 878, 868, 859, 850, 841, 832,
823, 814, 806, 797, 789, 780, 772, 764, 756, 748, 740, 732,
724, 717, 709, 702, 694, 687, 680, 673, 665, 658, 651, 644,
637, 631, 624, 617, 611, 604, 598, 591, 585, 578, 572, 566,
560, 554, 547, 541, 535, 530, 524, 518, 512, 506, 501, 495,
489, 484, 478, 473, 467, 462, 456, 451, 446, 441, 435, 430,
425, 420, 415, 410, 405, 400, 395, 390, 385, 380, 375, 371,
366, 361, 356, 352, 347, 343, 338, 333, 329, 324, 320, 316,
311, 307, 302, 298, 294, 289, 285, 281, 277, 273, 268, 264,
260, 256, 252, 248, 244, 240, 236, 232, 228, 224, 220, 216,
212, 209, 205, 201, 197, 194, 190, 186, 182, 179, 175, 171,
168, 164, 161, 157, 153, 150, 146, 143, 139, 136, 132, 129,
125, 122, 119, 115, 112, 109, 105, 102, 99, 95, 92, 89,
86, 82, 79, 76, 73, 70, 66, 63, 60, 57, 54, 51,
48, 45, 42, 38, 35, 32, 29, 26, 23, 20, 18, 15,
12, 9, 6, 3, 3};
static void cost(int *costs, vpx_tree tree, const vpx_prob *probs,
int i, int c) {
const vpx_prob prob = probs[i / 2];
int b;
for (b = 0; b <= 1; ++b) {
const int cc = c + vp9_cost_bit(prob, b);
const vpx_tree_index ii = tree[i + b];
if (ii <= 0)
costs[-ii] = cc;
else
cost(costs, tree, probs, ii, cc);
}
}
void vp9_cost_tokens(int *costs, const vpx_prob *probs, vpx_tree tree) {
cost(costs, tree, probs, 0, 0);
}
void vp9_cost_tokens_skip(int *costs, const vpx_prob *probs, vpx_tree tree) {
assert(tree[0] <= 0 && tree[1] > 0);
costs[-tree[0]] = vp9_cost_bit(probs[0], 0);
cost(costs, tree, probs, 2, 0);
}