PeerStreamer

/*

 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 *

 */

/**

 * @file cabac.c

 * Context Adaptive Binary Arithmetic Coder.

 */

#include <string.h>

#include "common.h"

#include "bitstream.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,

};

const uint8_t ff_h264_norm_shift[256]= {

 8,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4,

 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,

 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,

};

/**

 *

 * @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;

#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<<(CABAC_BITS + 1);

}

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+4]=

            c->lps_range[2*i+1][j+4]= 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

#include "avcodec.h"

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) )

            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 0

    for(i=0; i<SIZE; i++){

START_TIMER

        if( r[i] != get_cabac_u(&c, state, (i&1) ? 6 : 7, 3, i&1) )

            av_log(NULL, AV_LOG_ERROR, "CABAC unary (truncated) binarization failure at %d\n", 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))

            av_log(NULL, AV_LOG_ERROR, "CABAC unary (truncated) binarization failure at %d\n", i);

STOP_TIMER("get_cabac_ueg")

    }

#endif

    if(!get_cabac_terminate(&c))

        av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");

    return 0;

}

#endif