cabac.c.svn-base

现在关于h.264的源码很多

    int val = i_dqp <= 0 ? (-2*i_dqp) : (2*i_dqp - 1);
    int ctx;

    /* No need to test for PCM / SKIP */
    if( i_mbn_xy >= h->sh.i_first_mb && h->mb.i_last_dqp != 0 &&
        ( h->mb.type[i_mbn_xy] == I_16x16 || (h->mb.cbp[i_mbn_xy]&0x3f) ) )
        ctx = 1;
    else
        ctx = 0;

    while( val > 0 )
    {
        x264_cabac_encode_decision( cb, 60 + ctx, 1 );
        if( ctx < 2 )
            ctx = 2;
        else
            ctx = 3;
        val--;
    }
    x264_cabac_encode_decision( cb, 60 + ctx, 0 );
}

void x264_cabac_mb_skip( x264_t *h, int b_skip )
{
    int ctx = 0;

    if( h->mb.i_mb_type_left >= 0 && !IS_SKIP( h->mb.i_mb_type_left ) )
    {
        ctx++;
    }
    if( h->mb.i_mb_type_top >= 0 && !IS_SKIP( h->mb.i_mb_type_top ) )
    {
        ctx++;
    }

    if( h->sh.i_type == SLICE_TYPE_P )
        x264_cabac_encode_decision( &h->cabac, 11 + ctx, b_skip ? 1 : 0 );
    else /* SLICE_TYPE_B */
        x264_cabac_encode_decision( &h->cabac, 24 + ctx, b_skip ? 1 : 0 );
}

static inline void x264_cabac_mb_sub_p_partition( x264_cabac_t *cb, int i_sub )
{
    if( i_sub == D_L0_8x8 )
    {
        x264_cabac_encode_decision( cb, 21, 1 );
    }
    else if( i_sub == D_L0_8x4 )
    {
        x264_cabac_encode_decision( cb, 21, 0 );
        x264_cabac_encode_decision( cb, 22, 0 );
    }
    else if( i_sub == D_L0_4x8 )
    {
        x264_cabac_encode_decision( cb, 21, 0 );
        x264_cabac_encode_decision( cb, 22, 1 );
        x264_cabac_encode_decision( cb, 23, 1 );
    }
    else if( i_sub == D_L0_4x4 )
    {
        x264_cabac_encode_decision( cb, 21, 0 );
        x264_cabac_encode_decision( cb, 22, 1 );
        x264_cabac_encode_decision( cb, 23, 0 );
    }
}

static inline void x264_cabac_mb_sub_b_partition( x264_cabac_t *cb, int i_sub )
{
#define WRITE_SUB_3(a,b,c) {\
        x264_cabac_encode_decision( cb, 36, a );\
        x264_cabac_encode_decision( cb, 37, b );\
        x264_cabac_encode_decision( cb, 39, c );\
    }
#define WRITE_SUB_5(a,b,c,d,e) {\
        x264_cabac_encode_decision( cb, 36, a );\
        x264_cabac_encode_decision( cb, 37, b );\
        x264_cabac_encode_decision( cb, 38, c );\
        x264_cabac_encode_decision( cb, 39, d );\
        x264_cabac_encode_decision( cb, 39, e );\
    }
#define WRITE_SUB_6(a,b,c,d,e,f) {\
        WRITE_SUB_5(a,b,c,d,e)\
        x264_cabac_encode_decision( cb, 39, f );\
    }

    switch( i_sub )
    {
        case D_DIRECT_8x8:
            x264_cabac_encode_decision( cb, 36, 0 );
            break;
        case D_L0_8x8: WRITE_SUB_3(1,0,0); break;
        case D_L1_8x8: WRITE_SUB_3(1,0,1); break;
        case D_BI_8x8: WRITE_SUB_5(1,1,0,0,0); break;
        case D_L0_8x4: WRITE_SUB_5(1,1,0,0,1); break;
        case D_L0_4x8: WRITE_SUB_5(1,1,0,1,0); break;
        case D_L1_8x4: WRITE_SUB_5(1,1,0,1,1); break;
        case D_L1_4x8: WRITE_SUB_6(1,1,1,0,0,0); break;
        case D_BI_8x4: WRITE_SUB_6(1,1,1,0,0,1); break;
        case D_BI_4x8: WRITE_SUB_6(1,1,1,0,1,0); break;
        case D_L0_4x4: WRITE_SUB_6(1,1,1,0,1,1); break;
        case D_L1_4x4: WRITE_SUB_5(1,1,1,1,0); break;
        case D_BI_4x4: WRITE_SUB_5(1,1,1,1,1); break;
    }
}

static inline void x264_cabac_mb_transform_size( x264_t *h, x264_cabac_t *cb )
{
    int ctx = 399 + h->mb.cache.i_neighbour_transform_size;
    x264_cabac_encode_decision( cb, ctx, h->mb.b_transform_8x8 );
}

static inline void x264_cabac_mb_ref( x264_t *h, x264_cabac_t *cb, int i_list, int idx )
{
    const int i8 = x264_scan8[idx];
    const int i_refa = h->mb.cache.ref[i_list][i8 - 1];
    const int i_refb = h->mb.cache.ref[i_list][i8 - 8];
    int i_ref  = h->mb.cache.ref[i_list][i8];
    int ctx  = 0;

    if( i_refa > 0 && !h->mb.cache.skip[i8 - 1])
        ctx++;
    if( i_refb > 0 && !h->mb.cache.skip[i8 - 8])
        ctx += 2;

    while( i_ref > 0 )
    {
        x264_cabac_encode_decision( cb, 54 + ctx, 1 );
        if( ctx < 4 )
            ctx = 4;
        else
            ctx = 5;

        i_ref--;
    }
    x264_cabac_encode_decision( cb, 54 + ctx, 0 );
}



static inline void  x264_cabac_mb_mvd_cpn( x264_t *h, x264_cabac_t *cb, int i_list, int idx, int l, int mvd )
{
    const int amvd = abs( h->mb.cache.mvd[i_list][x264_scan8[idx] - 1][l] ) +
                     abs( h->mb.cache.mvd[i_list][x264_scan8[idx] - 8][l] );
    const int i_abs = abs( mvd );
    const int i_prefix = X264_MIN( i_abs, 9 );
    const int ctxbase = (l == 0 ? 40 : 47);
    int ctx;
    int i;


    if( amvd < 3 )
        ctx = 0;
    else if( amvd > 32 )
        ctx = 2;
    else
        ctx = 1;

    for( i = 0; i < i_prefix; i++ )
    {
        x264_cabac_encode_decision( cb, ctxbase + ctx, 1 );
        if( ctx < 3 )
            ctx = 3;
        else if( ctx < 6 )
            ctx++;
    }
    if( i_prefix < 9 )
        x264_cabac_encode_decision( cb, ctxbase + ctx, 0 );
    else
        x264_cabac_encode_ue_bypass( cb, 3, i_abs - 9 );

    /* sign */
    if( mvd > 0 )
        x264_cabac_encode_bypass( cb, 0 );
    else if( mvd < 0 )
        x264_cabac_encode_bypass( cb, 1 );
}

static inline void x264_cabac_mb_mvd( x264_t *h, x264_cabac_t *cb, int i_list, int idx, int width, int height )
{
    int mvp[2];
    int mdx, mdy;

    /* Calculate mvd */
    x264_mb_predict_mv( h, i_list, idx, width, mvp );
    mdx = h->mb.cache.mv[i_list][x264_scan8[idx]][0] - mvp[0];
    mdy = h->mb.cache.mv[i_list][x264_scan8[idx]][1] - mvp[1];

    /* encode */
    x264_cabac_mb_mvd_cpn( h, cb, i_list, idx, 0, mdx );
    x264_cabac_mb_mvd_cpn( h, cb, i_list, idx, 1, mdy );

    /* save value */
    x264_macroblock_cache_mvd( h, block_idx_x[idx], block_idx_y[idx], width, height, i_list, mdx, mdy );
}

static inline void x264_cabac_mb8x8_mvd( x264_t *h, x264_cabac_t *cb, int i_list )
{
    int i;
    for( i = 0; i < 4; i++ )
    {
        if( !x264_mb_partition_listX_table[i_list][ h->mb.i_sub_partition[i] ] )
        {
            continue;
        }

        switch( h->mb.i_sub_partition[i] )
        {
            case D_L0_8x8:
            case D_L1_8x8:
            case D_BI_8x8:
                x264_cabac_mb_mvd( h, cb, i_list, 4*i, 2, 2 );
                break;
            case D_L0_8x4:
            case D_L1_8x4:
            case D_BI_8x4:
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+0, 2, 1 );
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+2, 2, 1 );
                break;
            case D_L0_4x8:
            case D_L1_4x8:
            case D_BI_4x8:
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+0, 1, 2 );
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+1, 1, 2 );
                break;
            case D_L0_4x4:
            case D_L1_4x4:
            case D_BI_4x4:
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+0, 1, 1 );
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+1, 1, 1 );
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+2, 1, 1 );
                x264_cabac_mb_mvd( h, cb, i_list, 4*i+3, 1, 1 );
                break;
        }
    }
}

static int x264_cabac_mb_cbf_ctxidxinc( x264_t *h, int i_cat, int i_idx )
{
    /* TODO: clean up/optimize */
    int i_mba_xy = -1;
    int i_mbb_xy = -1;
    int i_nza = -1;
    int i_nzb = -1;
    int ctx = 4 * i_cat;

    if( i_cat == DCT_LUMA_DC )
    {
        if( h->mb.i_neighbour & MB_LEFT )
        {
            i_mba_xy = h->mb.i_mb_xy -1;
            if( h->mb.type[i_mba_xy] == I_16x16 )
            {
                i_nza = h->mb.cbp[i_mba_xy]&0x100;
            }
        }
        if( h->mb.i_neighbour & MB_TOP )
        {
            i_mbb_xy = h->mb.i_mb_xy - h->mb.i_mb_stride;
            if( h->mb.type[i_mbb_xy] == I_16x16 )
            {
                i_nzb = h->mb.cbp[i_mbb_xy]&0x100;
            }
        }
    }
    else if( i_cat == DCT_LUMA_AC || i_cat == DCT_LUMA_4x4 )
    {
        int x = block_idx_x[i_idx];
        int y = block_idx_y[i_idx];

        if( x > 0 )
            i_mba_xy = h->mb.i_mb_xy;
        else if( h->mb.i_neighbour & MB_LEFT )
            i_mba_xy = h->mb.i_mb_xy -1;

        if( y > 0 )
            i_mbb_xy = h->mb.i_mb_xy;
        else if( h->mb.i_neighbour & MB_TOP )
            i_mbb_xy = h->mb.i_mb_xy - h->mb.i_mb_stride;

        /* no need to test for skip/pcm */
        if( i_mba_xy >= 0 )
        {
            const int i8x8a = block_idx_xy[(x-1)&0x03][y]/4;
            if( (h->mb.cbp[i_mba_xy]&0x0f)>> i8x8a )
            {
                i_nza = h->mb.cache.non_zero_count[x264_scan8[i_idx] - 1];
            }
        }
        if( i_mbb_xy >= 0 )
        {
            const int i8x8b = block_idx_xy[x][(y-1)&0x03]/4;
            if( (h->mb.cbp[i_mbb_xy]&0x0f)>> i8x8b )
            {
                i_nzb = h->mb.cache.non_zero_count[x264_scan8[i_idx] - 8];
            }
        }
    }
    else if( i_cat == DCT_CHROMA_DC )
    {
        /* no need to test skip/pcm */
        if( h->mb.i_neighbour & MB_LEFT )
        {
            i_mba_xy = h->mb.i_mb_xy -1;
            if( h->mb.cbp[i_mba_xy]&0x30 )
            {
                i_nza = h->mb.cbp[i_mba_xy]&( 0x02 << ( 8 + i_idx) );
            }
        }
        if( h->mb.i_neighbour & MB_TOP )
        {
            i_mbb_xy = h->mb.i_mb_xy - h->mb.i_mb_stride;
            if( h->mb.cbp[i_mbb_xy]&0x30 )
            {
                i_nzb = h->mb.cbp[i_mbb_xy]&( 0x02 << ( 8 + i_idx) );
            }
        }
    }
    else if( i_cat == DCT_CHROMA_AC )
    {
        if( i_idx & 1 )
            i_mba_xy = h->mb.i_mb_xy;
        else if( h->mb.i_neighbour & MB_LEFT )
            i_mba_xy = h->mb.i_mb_xy - 1;

        if( i_idx & 2 )
            i_mbb_xy = h->mb.i_mb_xy;
        else if( h->mb.i_neighbour & MB_TOP )
            i_mbb_xy = h->mb.i_mb_xy - h->mb.i_mb_stride;

        /* no need to test skip/pcm */
        if( i_mba_xy >= 0 && (h->mb.cbp[i_mba_xy]&0x30) == 0x20 )
        {
            i_nza = h->mb.cache.non_zero_count[x264_scan8[16+i_idx] - 1];
        }
        if( i_mbb_xy >= 0 && (h->mb.cbp[i_mbb_xy]&0x30) == 0x20 )
        {
            i_nzb = h->mb.cache.non_zero_count[x264_scan8[16+i_idx] - 8];
        }
    }

    if( ( i_mba_xy < 0  && IS_INTRA( h->mb.i_type ) ) || i_nza > 0 )
    {
        ctx++;
    }
    if( ( i_mbb_xy < 0  && IS_INTRA( h->mb.i_type ) ) || i_nzb > 0 )
    {
        ctx += 2;
    }

    return ctx;
}


static const int significant_coeff_flag_offset[6] = { 105, 120, 134, 149, 152, 402 };
static const int last_coeff_flag_offset[6] = { 166, 181, 195, 210, 213, 417 };
static const int coeff_abs_level_m1_offset[6] = { 227, 237, 247, 257, 266, 426 };
static const int significant_coeff_flag_offset_8x8[63] = {
    0, 1, 2, 3, 4, 5, 5, 4, 4, 3, 3, 4, 4, 4, 5, 5,
    4, 4, 4, 4, 3, 3, 6, 7, 7, 7, 8, 9,10, 9, 8, 7,