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/*
* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Context Adaptive Binary Arithmetic Coder.
*/
#include <string.h>
#include "libavutil/common.h"
#include "get_bits.h"
#include "cabac.h"
#include "cabac_functions.h"
uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63] = {
9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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,
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,
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,
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,
};
static const uint8_t lps_range[64][4]= {
{128,176,208,240}, {128,167,197,227}, {128,158,187,216}, {123,150,178,205},
{116,142,169,195}, {111,135,160,185}, {105,128,152,175}, {100,122,144,166},
{ 95,116,137,158}, { 90,110,130,150}, { 85,104,123,142}, { 81, 99,117,135},
{ 77, 94,111,128}, { 73, 89,105,122}, { 69, 85,100,116}, { 66, 80, 95,110},
{ 62, 76, 90,104}, { 59, 72, 86, 99}, { 56, 69, 81, 94}, { 53, 65, 77, 89},
{ 51, 62, 73, 85}, { 48, 59, 69, 80}, { 46, 56, 66, 76}, { 43, 53, 63, 72},
{ 41, 50, 59, 69}, { 39, 48, 56, 65}, { 37, 45, 54, 62}, { 35, 43, 51, 59},
{ 33, 41, 48, 56}, { 32, 39, 46, 53}, { 30, 37, 43, 50}, { 29, 35, 41, 48},
{ 27, 33, 39, 45}, { 26, 31, 37, 43}, { 24, 30, 35, 41}, { 23, 28, 33, 39},
{ 22, 27, 32, 37}, { 21, 26, 30, 35}, { 20, 24, 29, 33}, { 19, 23, 27, 31},
{ 18, 22, 26, 30}, { 17, 21, 25, 28}, { 16, 20, 23, 27}, { 15, 19, 22, 25},
{ 14, 18, 21, 24}, { 14, 17, 20, 23}, { 13, 16, 19, 22}, { 12, 15, 18, 21},
{ 12, 14, 17, 20}, { 11, 14, 16, 19}, { 11, 13, 15, 18}, { 10, 12, 15, 17},
{ 10, 12, 14, 16}, { 9, 11, 13, 15}, { 9, 11, 12, 14}, { 8, 10, 12, 14},
{ 8, 9, 11, 13}, { 7, 9, 11, 12}, { 7, 9, 10, 12}, { 7, 8, 10, 11},
{ 6, 8, 9, 11}, { 6, 7, 9, 10}, { 6, 7, 8, 9}, { 2, 2, 2, 2},
};
static const uint8_t mps_state[64]= {
1, 2, 3, 4, 5, 6, 7, 8,
9,10,11,12,13,14,15,16,
17,18,19,20,21,22,23,24,
25,26,27,28,29,30,31,32,
33,34,35,36,37,38,39,40,
41,42,43,44,45,46,47,48,
49,50,51,52,53,54,55,56,
57,58,59,60,61,62,62,63,
};
static const uint8_t lps_state[64]= {
0, 0, 1, 2, 2, 4, 4, 5,
6, 7, 8, 9, 9,11,11,12,
13,13,15,15,16,16,18,18,
19,19,21,21,22,22,23,24,
24,25,26,26,27,27,28,29,
29,30,30,30,31,32,32,33,
33,33,34,34,35,35,35,36,
36,36,37,37,37,38,38,63,
};
static const uint8_t last_coeff_flag_offset_8x8[63] = {
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
};
/**
*
* @param buf_size size of buf in bits
*/
void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
init_put_bits(&c->pb, buf, buf_size);
c->low= 0;
c->range= 0x1FE;
c->outstanding_count= 0;
c->pb.bit_left++; //avoids firstBitFlag
}
/**
*
* @param buf_size size of buf in bits
*/
void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
c->bytestream_start=
c->bytestream= buf;
c->bytestream_end= buf + buf_size;
#if CABAC_BITS == 16
c->low = (*c->bytestream++)<<18;
c->low+= (*c->bytestream++)<<10;
#else
c->low = (*c->bytestream++)<<10;
#endif
c->low+= ((*c->bytestream++)<<2) + 2;
c->range= 0x1FE;
}
void ff_init_cabac_states(void)
{
int i, j;
static int initialized = 0;
if (initialized)
return;
for(i=0; i<64; i++){
for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save
ff_h264_lps_range[j*2*64+2*i+0]=
ff_h264_lps_range[j*2*64+2*i+1]= lps_range[i][j];
}
ff_h264_mlps_state[128 + 2 * i + 0] = 2 * mps_state[i] + 0;
ff_h264_mlps_state[128 + 2 * i + 1] = 2 * mps_state[i] + 1;
if( i ){
ff_h264_mlps_state[128-2*i-1]= 2*lps_state[i]+0;
ff_h264_mlps_state[128-2*i-2]= 2*lps_state[i]+1;
}else{
ff_h264_mlps_state[128-2*i-1]= 1;
ff_h264_mlps_state[128-2*i-2]= 0;
}
}
for(i=0; i< 63; i++){
ff_h264_last_coeff_flag_offset_8x8[i] = last_coeff_flag_offset_8x8[i];
}
initialized = 1;
}
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