cabac.c
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上传日期:2021-12-09
资源大小:5084k
文件大小:6k
源码类别:
Audio
开发平台:
Visual C++
- /*
- * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
- * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
- *
- * This library 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 of the License, or (at your option) any later version.
- *
- * This library 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 this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- */
- /**
- * @file cabac.c
- * Context Adaptive Binary Arithmetic Coder.
- */
- #include <string.h>
- #include "common.h"
- #include "cabac.h"
- const uint8_t ff_h264_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},
- };
- const uint8_t ff_h264_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,
- };
- const uint8_t ff_h264_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,
- };
- /**
- *
- * @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;
- #ifdef STRICT_LIMITS
- c->sym_count =0;
- #endif
- 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;
- c->low= *c->bytestream++;
- c->low= (c->low<<9) + ((*c->bytestream++)<<1);
- c->range= 0x1FE00;
- c->bits_left= 7;
- }
- void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4],
- uint8_t const *mps_state, uint8_t const *lps_state, int state_count){
- int i, j;
- for(i=0; i<state_count; i++){
- for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save
- c->lps_range[2*i+0][j]=
- c->lps_range[2*i+1][j]= lps_range[i][j];
- }
- c->mps_state[2*i+0]= 2*mps_state[i];
- c->mps_state[2*i+1]= 2*mps_state[i]+1;
- if( i ){
- c->lps_state[2*i+0]= 2*lps_state[i];
- c->lps_state[2*i+1]= 2*lps_state[i]+1;
- }else{
- c->lps_state[2*i+0]= 1;
- c->lps_state[2*i+1]= 0;
- }
- }
- }
- #if 0 //selftest
- #define SIZE 10240
- int main(){
- CABACContext c;
- uint8_t b[9*SIZE];
- uint8_t r[9*SIZE];
- int i;
- uint8_t state[10]= {0};
- ff_init_cabac_encoder(&c, b, SIZE);
- ff_init_cabac_states(&c, ff_h264_lps_range, ff_h264_mps_state, ff_h264_lps_state, 64);
- for(i=0; i<SIZE; i++){
- r[i]= random()%7;
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- put_cabac_bypass(&c, r[i]&1);
- STOP_TIMER("put_cabac_bypass")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- put_cabac(&c, state, r[i]&1);
- STOP_TIMER("put_cabac")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- put_cabac_u(&c, state, r[i], 6, 3, i&1);
- STOP_TIMER("put_cabac_u")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- put_cabac_ueg(&c, state, r[i], 3, 0, 1, 2);
- STOP_TIMER("put_cabac_ueg")
- }
- put_cabac_terminate(&c, 1);
- ff_init_cabac_decoder(&c, b, SIZE);
- memset(state, 0, sizeof(state));
- for(i=0; i<SIZE; i++){
- START_TIMER
- if( (r[i]&1) != get_cabac_bypass(&c) )
- printf("CABAC bypass failure at %dn", i);
- STOP_TIMER("get_cabac_bypass")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- if( (r[i]&1) != get_cabac(&c, state) )
- printf("CABAC failure at %dn", i);
- STOP_TIMER("get_cabac")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- if( r[i] != get_cabac_u(&c, state, (i&1) ? 6 : 7, 3, i&1) )
- printf("CABAC unary (truncated) binarization failure at %dn", i);
- STOP_TIMER("get_cabac_u")
- }
- for(i=0; i<SIZE; i++){
- START_TIMER
- if( r[i] != get_cabac_ueg(&c, state, 3, 0, 1, 2))
- printf("CABAC unary (truncated) binarization failure at %dn", i);
- STOP_TIMER("get_cabac_ueg")
- }
- if(!get_cabac_terminate(&c))
- printf("where's the Terminator?n");
- return 0;
- }
- #endif