/* * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * FFmpeg 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. * * FFmpeg 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 FFmpeg; 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 uint8_t h264_lps_state[2*64]; static uint8_t h264_mps_state[2*64]; 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(){ int i, j; 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]= h264_mps_state[2 * i + 0] = 2 * mps_state[i] + 0; ff_h264_mlps_state[128+2*i+1]= h264_mps_state[2 * i + 1] = 2 * mps_state[i] + 1; if( i ){ h264_lps_state[2*i+0]= ff_h264_mlps_state[128-2*i-1]= 2*lps_state[i]+0; h264_lps_state[2*i+1]= ff_h264_mlps_state[128-2*i-2]= 2*lps_state[i]+1; }else{ h264_lps_state[2*i+0]= ff_h264_mlps_state[128-2*i-1]= 1; h264_lps_state[2*i+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]; } } #ifdef TEST #define SIZE 10240 #include "libavutil/lfg.h" #include "avcodec.h" #include "cabac.h" static inline void put_cabac_bit(CABACContext *c, int b){ put_bits(&c->pb, 1, b); for(;c->outstanding_count; c->outstanding_count--){ put_bits(&c->pb, 1, 1-b); } } static inline void renorm_cabac_encoder(CABACContext *c){ while(c->range < 0x100){ //FIXME optimize if(c->low<0x100){ put_cabac_bit(c, 0); }else if(c->low<0x200){ c->outstanding_count++; c->low -= 0x100; }else{ put_cabac_bit(c, 1); c->low -= 0x200; } c->range+= c->range; c->low += c->low; } } static void put_cabac(CABACContext *c, uint8_t * const state, int bit){ int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state]; if(bit == ((*state)&1)){ c->range -= RangeLPS; *state = h264_mps_state[*state]; }else{ c->low += c->range - RangeLPS; c->range = RangeLPS; *state= h264_lps_state[*state]; } renorm_cabac_encoder(c); } /** * @param bit 0 -> write zero bit, !=0 write one bit */ static void put_cabac_bypass(CABACContext *c, int bit){ c->low += c->low; if(bit){ c->low += c->range; } //FIXME optimize if(c->low<0x200){ put_cabac_bit(c, 0); }else if(c->low<0x400){ c->outstanding_count++; c->low -= 0x200; }else{ put_cabac_bit(c, 1); c->low -= 0x400; } } /** * * @return the number of bytes written */ static int put_cabac_terminate(CABACContext *c, int bit){ c->range -= 2; if(!bit){ renorm_cabac_encoder(c); }else{ c->low += c->range; c->range= 2; renorm_cabac_encoder(c); av_assert0(c->low <= 0x1FF); put_cabac_bit(c, c->low>>9); put_bits(&c->pb, 2, ((c->low>>7)&3)|1); flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong } return (put_bits_count(&c->pb)+7)>>3; } int main(void){ CABACContext c; uint8_t b[9*SIZE]; uint8_t r[9*SIZE]; int i; uint8_t state[10]= {0}; AVLFG prng; av_lfg_init(&prng, 1); ff_init_cabac_encoder(&c, b, SIZE); ff_init_cabac_states(); for(i=0; i<SIZE; i++){ if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7; else r[i] = (i>>8)&1; } 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") } 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) ) av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i); STOP_TIMER("get_cabac_bypass") } for(i=0; i<SIZE; i++){ START_TIMER if( (r[i]&1) != get_cabac(&c, state) ) av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i); STOP_TIMER("get_cabac") } if(!get_cabac_terminate(&c)) av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n"); return 0; } #endif /* TEST */