diff options
Diffstat (limited to 'libavcodec/cabac.c')
| -rw-r--r-- | libavcodec/cabac.c | 164 |
1 files changed, 159 insertions, 5 deletions
diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c index 6ba9303dc1..187b7dc445 100644 --- a/libavcodec/cabac.c +++ b/libavcodec/cabac.c @@ -2,20 +2,20 @@ * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * 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. * - * Libav is distributed in the hope that it will be useful, + * 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 Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -73,7 +73,8 @@ static const uint8_t lps_range[64][4]= { { 6, 8, 9, 11}, { 6, 7, 9, 10}, { 6, 7, 8, 9}, { 2, 2, 2, 2}, }; -static uint8_t h264_mps_state[2 * 64]; +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, @@ -152,10 +153,14 @@ void ff_init_cabac_states(void) 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; } } @@ -163,3 +168,152 @@ void ff_init_cabac_states(void) 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 */ |