mirror of
https://git.ffmpeg.org/ffmpeg.git
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311 lines
8.7 KiB
C
311 lines
8.7 KiB
C
/*
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* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Context Adaptive Binary Arithmetic Coder.
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*/
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#include <string.h>
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#include "libavutil/common.h"
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#include "get_bits.h"
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#include "cabac.h"
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#include "cabac_functions.h"
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static const uint8_t lps_range[64][4]= {
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{128,176,208,240}, {128,167,197,227}, {128,158,187,216}, {123,150,178,205},
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{116,142,169,195}, {111,135,160,185}, {105,128,152,175}, {100,122,144,166},
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{ 95,116,137,158}, { 90,110,130,150}, { 85,104,123,142}, { 81, 99,117,135},
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{ 77, 94,111,128}, { 73, 89,105,122}, { 69, 85,100,116}, { 66, 80, 95,110},
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{ 62, 76, 90,104}, { 59, 72, 86, 99}, { 56, 69, 81, 94}, { 53, 65, 77, 89},
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{ 51, 62, 73, 85}, { 48, 59, 69, 80}, { 46, 56, 66, 76}, { 43, 53, 63, 72},
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{ 41, 50, 59, 69}, { 39, 48, 56, 65}, { 37, 45, 54, 62}, { 35, 43, 51, 59},
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{ 33, 41, 48, 56}, { 32, 39, 46, 53}, { 30, 37, 43, 50}, { 29, 35, 41, 48},
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{ 27, 33, 39, 45}, { 26, 31, 37, 43}, { 24, 30, 35, 41}, { 23, 28, 33, 39},
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{ 22, 27, 32, 37}, { 21, 26, 30, 35}, { 20, 24, 29, 33}, { 19, 23, 27, 31},
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{ 18, 22, 26, 30}, { 17, 21, 25, 28}, { 16, 20, 23, 27}, { 15, 19, 22, 25},
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{ 14, 18, 21, 24}, { 14, 17, 20, 23}, { 13, 16, 19, 22}, { 12, 15, 18, 21},
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{ 12, 14, 17, 20}, { 11, 14, 16, 19}, { 11, 13, 15, 18}, { 10, 12, 15, 17},
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{ 10, 12, 14, 16}, { 9, 11, 13, 15}, { 9, 11, 12, 14}, { 8, 10, 12, 14},
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{ 8, 9, 11, 13}, { 7, 9, 11, 12}, { 7, 9, 10, 12}, { 7, 8, 10, 11},
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{ 6, 8, 9, 11}, { 6, 7, 9, 10}, { 6, 7, 8, 9}, { 2, 2, 2, 2},
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};
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uint8_t ff_h264_mlps_state[4*64];
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uint8_t ff_h264_lps_range[4*2*64];
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uint8_t ff_h264_lps_state[2*64];
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static uint8_t h264_mps_state[2 * 64];
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static const uint8_t mps_state[64]= {
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1, 2, 3, 4, 5, 6, 7, 8,
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9,10,11,12,13,14,15,16,
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17,18,19,20,21,22,23,24,
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25,26,27,28,29,30,31,32,
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33,34,35,36,37,38,39,40,
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41,42,43,44,45,46,47,48,
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49,50,51,52,53,54,55,56,
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57,58,59,60,61,62,62,63,
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};
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static const uint8_t lps_state[64]= {
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0, 0, 1, 2, 2, 4, 4, 5,
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6, 7, 8, 9, 9,11,11,12,
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13,13,15,15,16,16,18,18,
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19,19,21,21,22,22,23,24,
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24,25,26,26,27,27,28,29,
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29,30,30,30,31,32,32,33,
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33,33,34,34,35,35,35,36,
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36,36,37,37,37,38,38,63,
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};
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const uint8_t ff_h264_norm_shift[512]= {
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9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
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4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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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,
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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,
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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,
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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,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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};
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/**
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*
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* @param buf_size size of buf in bits
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*/
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void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
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init_put_bits(&c->pb, buf, buf_size);
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c->low= 0;
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c->range= 0x1FE;
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c->outstanding_count= 0;
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c->pb.bit_left++; //avoids firstBitFlag
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}
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/**
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*
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* @param buf_size size of buf in bits
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*/
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void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
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c->bytestream_start=
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c->bytestream= buf;
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c->bytestream_end= buf + buf_size;
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#if CABAC_BITS == 16
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c->low = (*c->bytestream++)<<18;
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c->low+= (*c->bytestream++)<<10;
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#else
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c->low = (*c->bytestream++)<<10;
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#endif
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c->low+= ((*c->bytestream++)<<2) + 2;
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c->range= 0x1FE;
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}
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void ff_init_cabac_states(CABACContext *c){
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int i, j;
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for(i=0; i<64; i++){
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for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save
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ff_h264_lps_range[j*2*64+2*i+0]=
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ff_h264_lps_range[j*2*64+2*i+1]= lps_range[i][j];
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}
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ff_h264_mlps_state[128+2*i+0]=
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h264_mps_state[2 * i + 0] = 2 * mps_state[i] + 0;
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ff_h264_mlps_state[128+2*i+1]=
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h264_mps_state[2 * i + 1] = 2 * mps_state[i] + 1;
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if( i ){
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ff_h264_lps_state[2*i+0]=
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ff_h264_mlps_state[128-2*i-1]= 2*lps_state[i]+0;
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ff_h264_lps_state[2*i+1]=
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ff_h264_mlps_state[128-2*i-2]= 2*lps_state[i]+1;
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}else{
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ff_h264_lps_state[2*i+0]=
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ff_h264_mlps_state[128-2*i-1]= 1;
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ff_h264_lps_state[2*i+1]=
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ff_h264_mlps_state[128-2*i-2]= 0;
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}
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}
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}
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#ifdef TEST
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#define SIZE 10240
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#include "libavutil/lfg.h"
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#include "avcodec.h"
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#include "cabac.h"
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static inline void put_cabac_bit(CABACContext *c, int b){
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put_bits(&c->pb, 1, b);
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for(;c->outstanding_count; c->outstanding_count--){
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put_bits(&c->pb, 1, 1-b);
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}
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}
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static inline void renorm_cabac_encoder(CABACContext *c){
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while(c->range < 0x100){
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//FIXME optimize
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if(c->low<0x100){
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put_cabac_bit(c, 0);
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}else if(c->low<0x200){
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c->outstanding_count++;
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c->low -= 0x100;
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}else{
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put_cabac_bit(c, 1);
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c->low -= 0x200;
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}
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c->range+= c->range;
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c->low += c->low;
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}
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}
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static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
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int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
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if(bit == ((*state)&1)){
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c->range -= RangeLPS;
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*state = h264_mps_state[*state];
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}else{
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c->low += c->range - RangeLPS;
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c->range = RangeLPS;
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*state= ff_h264_lps_state[*state];
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}
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renorm_cabac_encoder(c);
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}
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/**
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* @param bit 0 -> write zero bit, !=0 write one bit
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*/
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static void put_cabac_bypass(CABACContext *c, int bit){
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c->low += c->low;
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if(bit){
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c->low += c->range;
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}
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//FIXME optimize
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if(c->low<0x200){
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put_cabac_bit(c, 0);
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}else if(c->low<0x400){
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c->outstanding_count++;
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c->low -= 0x200;
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}else{
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put_cabac_bit(c, 1);
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c->low -= 0x400;
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}
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}
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/**
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*
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* @return the number of bytes written
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*/
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static int put_cabac_terminate(CABACContext *c, int bit){
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c->range -= 2;
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if(!bit){
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renorm_cabac_encoder(c);
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}else{
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c->low += c->range;
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c->range= 2;
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renorm_cabac_encoder(c);
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assert(c->low <= 0x1FF);
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put_cabac_bit(c, c->low>>9);
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put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
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flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
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}
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return (put_bits_count(&c->pb)+7)>>3;
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}
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int main(void){
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CABACContext c;
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uint8_t b[9*SIZE];
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uint8_t r[9*SIZE];
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int i;
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uint8_t state[10]= {0};
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AVLFG prng;
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av_lfg_init(&prng, 1);
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ff_init_cabac_encoder(&c, b, SIZE);
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ff_init_cabac_states(&c);
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for(i=0; i<SIZE; i++){
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if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7;
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else r[i] = (i>>8)&1;
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}
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for(i=0; i<SIZE; i++){
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START_TIMER
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put_cabac_bypass(&c, r[i]&1);
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STOP_TIMER("put_cabac_bypass")
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}
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for(i=0; i<SIZE; i++){
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START_TIMER
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put_cabac(&c, state, r[i]&1);
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STOP_TIMER("put_cabac")
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}
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put_cabac_terminate(&c, 1);
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ff_init_cabac_decoder(&c, b, SIZE);
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memset(state, 0, sizeof(state));
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for(i=0; i<SIZE; i++){
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START_TIMER
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if( (r[i]&1) != get_cabac_bypass(&c) )
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av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
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STOP_TIMER("get_cabac_bypass")
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}
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for(i=0; i<SIZE; i++){
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START_TIMER
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if( (r[i]&1) != get_cabac(&c, state) )
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av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
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STOP_TIMER("get_cabac")
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}
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if(!get_cabac_terminate(&c))
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av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");
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return 0;
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}
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#endif /* TEST */
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