ref: ddb6edd8317904d96db6c06979f48c1690146f69
dir: /vp8/encoder/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 "boolhuff.h"
#include "vp8/common/blockd.h"
#if defined(SECTIONBITS_OUTPUT)
unsigned __int64 Sectionbits[500];
#endif
#ifdef ENTROPY_STATS
unsigned int active_section = 0;
#endif
const unsigned int vp8_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 vp8_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 vp8_stop_encode(BOOL_CODER *br)
{
int i;
for (i = 0; i < 32; i++)
vp8_encode_bool(br, 0, 128);
}
DECLARE_ALIGNED(16, static const unsigned int, norm[256]) =
{
0, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
void vp8_encode_bool(BOOL_CODER *br, int bit, int probability)
{
unsigned int split;
int count = br->count;
unsigned int range = br->range;
unsigned int lowvalue = br->lowvalue;
register unsigned int shift;
#ifdef ENTROPY_STATS
#if defined(SECTIONBITS_OUTPUT)
if (bit)
Sectionbits[active_section] += vp8_prob_cost[255-probability];
else
Sectionbits[active_section] += vp8_prob_cost[probability];
#endif
#endif
split = 1 + (((range - 1) * probability) >> 8);
range = split;
if (bit)
{
lowvalue += split;
range = br->range - split;
}
shift = norm[range];
range <<= shift;
count += shift;
if (count >= 0)
{
int offset = shift - count;
if ((lowvalue << (offset - 1)) & 0x80000000)
{
int x = br->pos - 1;
while (x >= 0 && br->buffer[x] == 0xff)
{
br->buffer[x] = (unsigned char)0;
x--;
}
br->buffer[x] += 1;
}
br->buffer[br->pos++] = (lowvalue >> (24 - offset));
lowvalue <<= offset;
shift = count;
lowvalue &= 0xffffff;
count -= 8 ;
}
lowvalue <<= shift;
br->count = count;
br->lowvalue = lowvalue;
br->range = range;
}
void vp8_encode_value(BOOL_CODER *br, int data, int bits)
{
int bit;
for (bit = bits - 1; bit >= 0; bit--)
vp8_encode_bool(br, (1 & (data >> bit)), 0x80);
}