diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2003-05-28 22:44:52 +0400 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2003-05-28 22:44:52 +0400 |
commit | d592f67fb6e5abbdb93a6f38f7c2b1bb5686c35b (patch) | |
tree | 6787850b3dd00e39df2c7cdc701a57579317192b /libavcodec/cabac.c | |
parent | 8e7284ba915389212f55a2310b0767f2fb40aed7 (diff) |
CABAC
note, this is just the CABAC (de)coder not complete h264-cabac support
Originally committed as revision 1915 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/cabac.c')
-rw-r--r-- | libavcodec/cabac.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c new file mode 100644 index 0000000000..4d018823f2 --- /dev/null +++ b/libavcodec/cabac.c @@ -0,0 +1,179 @@ +/* + * 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, NULL, NULL); + + 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, uint8_t *buf, int buf_size){ + c->bytestream= buf; + + 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(lps_state[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 bit[9*SIZE]; + int i; + uint8_t state= 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++){ + bit[i]= (random()%7)&1; + } + + for(i=0; i<SIZE; i++){ +START_TIMER + put_cabac_bypass(&c, bit[i]); +STOP_TIMER("put_cabac_bypass") + } + + for(i=0; i<SIZE; i++){ +START_TIMER + put_cabac(&c, &state, bit[i]); +STOP_TIMER("put_cabac") + } + + put_cabac_terminate(&c, 1); + + ff_init_cabac_decoder(&c, b, SIZE); + + state=0; + + for(i=0; i<SIZE; i++){ +START_TIMER + if( bit[i] != get_cabac_bypass(&c) ) + printf("CABAC bypass failure at %d\n", i); +STOP_TIMER("get_cabac_bypass") + } + + for(i=0; i<SIZE; i++){ +START_TIMER + if( bit[i] != get_cabac(&c, &state) ) + printf("CABAC failure at %d\n", i); +STOP_TIMER("get_cabac") + } + + if(!get_cabac_terminate(&c)) + printf("where's the Terminator?\n"); + + return 0; +} + +#endif |