ref: fcccbcbb395ce4cf31b54ce1245cc28e5e3ef4c1
dir: /vp9/encoder/vp9_boolhuff.c/
/*
* Copyright (c) 2010 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_boolhuff.h"
#if defined(SECTIONBITS_OUTPUT)
unsigned __int64 Sectionbits[500];
#endif
#ifdef ENTROPY_STATS
unsigned int active_section = 0;
#endif
const unsigned int vp9_prob_cost[256] = {
2047, 2047, 1791, 1641, 1535, 1452, 1385, 1328, 1279, 1235, 1196, 1161, 1129, 1099, 1072, 1046,
1023, 1000, 979, 959, 940, 922, 905, 889, 873, 858, 843, 829, 816, 803, 790, 778,
767, 755, 744, 733, 723, 713, 703, 693, 684, 675, 666, 657, 649, 641, 633, 625,
617, 609, 602, 594, 587, 580, 573, 567, 560, 553, 547, 541, 534, 528, 522, 516,
511, 505, 499, 494, 488, 483, 477, 472, 467, 462, 457, 452, 447, 442, 437, 433,
428, 424, 419, 415, 410, 406, 401, 397, 393, 389, 385, 381, 377, 373, 369, 365,
361, 357, 353, 349, 346, 342, 338, 335, 331, 328, 324, 321, 317, 314, 311, 307,
304, 301, 297, 294, 291, 288, 285, 281, 278, 275, 272, 269, 266, 263, 260, 257,
255, 252, 249, 246, 243, 240, 238, 235, 232, 229, 227, 224, 221, 219, 216, 214,
211, 208, 206, 203, 201, 198, 196, 194, 191, 189, 186, 184, 181, 179, 177, 174,
172, 170, 168, 165, 163, 161, 159, 156, 154, 152, 150, 148, 145, 143, 141, 139,
137, 135, 133, 131, 129, 127, 125, 123, 121, 119, 117, 115, 113, 111, 109, 107,
105, 103, 101, 99, 97, 95, 93, 92, 90, 88, 86, 84, 82, 81, 79, 77,
75, 73, 72, 70, 68, 66, 65, 63, 61, 60, 58, 56, 55, 53, 51, 50,
48, 46, 45, 43, 41, 40, 38, 37, 35, 33, 32, 30, 29, 27, 25, 24,
22, 21, 19, 18, 16, 15, 13, 12, 10, 9, 7, 6, 4, 3, 1, 1
};
void vp9_start_encode(BOOL_CODER *br, unsigned char *source) {
br->lowvalue = 0;
br->range = 255;
br->value = 0;
br->count = -24;
br->buffer = source;
br->pos = 0;
}
void vp9_stop_encode(BOOL_CODER *br) {
int i;
for (i = 0; i < 32; i++)
encode_bool(br, 0, 128);
}
void vp9_encode_value(BOOL_CODER *br, int data, int bits) {
int bit;
for (bit = bits - 1; bit >= 0; bit--)
encode_bool(br, (1 & (data >> bit)), 0x80);
}
int vp9_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 get_unsigned_bits(unsigned num_values) {
int cat = 0;
if ((num_values--) <= 1) return 0;
while (num_values > 0) {
cat++;
num_values >>= 1;
}
return cat;
}
void vp9_encode_uniform(BOOL_CODER *br, int v, int n) {
int l = get_unsigned_bits(n);
int m;
if (l == 0) return;
m = (1 << l) - n;
if (v < m)
vp9_encode_value(br, v, l - 1);
else {
vp9_encode_value(br, m + ((v - m) >> 1), l - 1);
vp9_encode_value(br, (v - m) & 1, 1);
}
}
int vp9_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;
}
void vp9_encode_term_subexp(BOOL_CODER *br, 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) {
vp9_encode_uniform(br, word - mk, num_syms - mk);
break;
} else {
int t = (word >= mk + a);
vp9_encode_value(br, t, 1);
if (t) {
i = i + 1;
mk += a;
} else {
vp9_encode_value(br, word - mk, b);
break;
}
}
}
}
int vp9_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 += vp9_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;
}