h263.c

mediastreamer2是开源的网络传输媒体流的库

        else
            qp_lc= s->current_picture.qscale_table[xy-1];

        if(qp_lc){
            s->dsp.h263_h_loop_filter(dest_y,   linesize, qp_lc);
            if(s->mb_y + 1 == s->mb_height){
                const int chroma_qp= s->chroma_qscale_table[qp_lc];
                s->dsp.h263_h_loop_filter(dest_y +8*  linesize,   linesize, qp_lc);
                s->dsp.h263_h_loop_filter(dest_cb             , uvlinesize, chroma_qp);
                s->dsp.h263_h_loop_filter(dest_cr             , uvlinesize, chroma_qp);
            }
        }
    }
}

#ifdef CONFIG_ENCODERS
static int h263_pred_dc(MpegEncContext * s, int n, int16_t **dc_val_ptr)
{
    int x, y, wrap, a, c, pred_dc, scale;
    int16_t *dc_val;

    /* find prediction */
    if (n < 4) {
        x = 2 * s->mb_x + (n & 1);
        y = 2 * s->mb_y + ((n & 2) >> 1);
        wrap = s->b8_stride;
        dc_val = s->dc_val[0];
        scale = s->y_dc_scale;
    } else {
        x = s->mb_x;
        y = s->mb_y;
        wrap = s->mb_stride;
        dc_val = s->dc_val[n - 4 + 1];
        scale = s->c_dc_scale;
    }
    /* B C
     * A X
     */
    a = dc_val[(x - 1) + (y) * wrap];
    c = dc_val[(x) + (y - 1) * wrap];

    /* No prediction outside GOB boundary */
    if(s->first_slice_line && n!=3){
        if(n!=2) c= 1024;
        if(n!=1 && s->mb_x == s->resync_mb_x) a= 1024;
    }
    pred_dc = 1024;
    /* just DC prediction */
    if (a != 1024 && c != 1024)
        pred_dc = (a + c) >> 1;
    else if (a != 1024)
        pred_dc = a;
    else
        pred_dc = c;

    /* we assume pred is positive */
    //pred_dc = (pred_dc + (scale >> 1)) / scale;
    *dc_val_ptr = &dc_val[x + y * wrap];
    return pred_dc;
}
#endif /* CONFIG_ENCODERS */

static void h263_pred_acdc(MpegEncContext * s, DCTELEM *block, int n)
{
    int x, y, wrap, a, c, pred_dc, scale, i;
    int16_t *dc_val, *ac_val, *ac_val1;

    /* find prediction */
    if (n < 4) {
        x = 2 * s->mb_x + (n & 1);
        y = 2 * s->mb_y + (n>> 1);
        wrap = s->b8_stride;
        dc_val = s->dc_val[0];
        ac_val = s->ac_val[0][0];
        scale = s->y_dc_scale;
    } else {
        x = s->mb_x;
        y = s->mb_y;
        wrap = s->mb_stride;
        dc_val = s->dc_val[n - 4 + 1];
        ac_val = s->ac_val[n - 4 + 1][0];
        scale = s->c_dc_scale;
    }

    ac_val += ((y) * wrap + (x)) * 16;
    ac_val1 = ac_val;

    /* B C
     * A X
     */
    a = dc_val[(x - 1) + (y) * wrap];
    c = dc_val[(x) + (y - 1) * wrap];

    /* No prediction outside GOB boundary */
    if(s->first_slice_line && n!=3){
        if(n!=2) c= 1024;
        if(n!=1 && s->mb_x == s->resync_mb_x) a= 1024;
    }

    if (s->ac_pred) {
        pred_dc = 1024;
        if (s->h263_aic_dir) {
            /* left prediction */
            if (a != 1024) {
                ac_val -= 16;
                for(i=1;i<8;i++) {
                    block[s->dsp.idct_permutation[i<<3]] += ac_val[i];
                }
                pred_dc = a;
            }
        } else {
            /* top prediction */
            if (c != 1024) {
                ac_val -= 16 * wrap;
                for(i=1;i<8;i++) {
                    block[s->dsp.idct_permutation[i   ]] += ac_val[i + 8];
                }
                pred_dc = c;
            }
        }
    } else {
        /* just DC prediction */
        if (a != 1024 && c != 1024)
            pred_dc = (a + c) >> 1;
        else if (a != 1024)
            pred_dc = a;
        else
            pred_dc = c;
    }

    /* we assume pred is positive */
    block[0]=block[0]*scale + pred_dc;

    if (block[0] < 0)
        block[0] = 0;
    else
        block[0] |= 1;

    /* Update AC/DC tables */
    dc_val[(x) + (y) * wrap] = block[0];

    /* left copy */
    for(i=1;i<8;i++)
        ac_val1[i    ] = block[s->dsp.idct_permutation[i<<3]];
    /* top copy */
    for(i=1;i<8;i++)
        ac_val1[8 + i] = block[s->dsp.idct_permutation[i   ]];
}

int16_t *h263_pred_motion(MpegEncContext * s, int block, int dir,
                        int *px, int *py)
{
    int wrap;
    int16_t *A, *B, *C, (*mot_val)[2];
    static const int off[4]= {2, 1, 1, -1};

    wrap = s->b8_stride;
    mot_val = s->current_picture.motion_val[dir] + s->block_index[block];

    A = mot_val[ - 1];
    /* special case for first (slice) line */
    if (s->first_slice_line && block<3) {
        // we can't just change some MVs to simulate that as we need them for the B frames (and ME)
        // and if we ever support non rectangular objects than we need to do a few ifs here anyway :(
        if(block==0){ //most common case
            if(s->mb_x  == s->resync_mb_x){ //rare
                *px= *py = 0;
            }else if(s->mb_x + 1 == s->resync_mb_x && s->h263_pred){ //rare
                C = mot_val[off[block] - wrap];
                if(s->mb_x==0){
                    *px = C[0];
                    *py = C[1];
                }else{
                    *px = mid_pred(A[0], 0, C[0]);
                    *py = mid_pred(A[1], 0, C[1]);
                }
            }else{
                *px = A[0];
                *py = A[1];
            }
        }else if(block==1){
            if(s->mb_x + 1 == s->resync_mb_x && s->h263_pred){ //rare
                C = mot_val[off[block] - wrap];
                *px = mid_pred(A[0], 0, C[0]);
                *py = mid_pred(A[1], 0, C[1]);
            }else{
                *px = A[0];
                *py = A[1];
            }
        }else{ /* block==2*/
            B = mot_val[ - wrap];
            C = mot_val[off[block] - wrap];
            if(s->mb_x == s->resync_mb_x) //rare
                A[0]=A[1]=0;

            *px = mid_pred(A[0], B[0], C[0]);
            *py = mid_pred(A[1], B[1], C[1]);
        }
    } else {
        B = mot_val[ - wrap];
        C = mot_val[off[block] - wrap];
        *px = mid_pred(A[0], B[0], C[0]);
        *py = mid_pred(A[1], B[1], C[1]);
    }
    return *mot_val;
}

#ifdef CONFIG_ENCODERS
void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
{
    int range, l, bit_size, sign, code, bits;

    if (val == 0) {
        /* zero vector */
        code = 0;
        put_bits(&s->pb, mvtab[code][1], mvtab[code][0]);
    } else {
        bit_size = f_code - 1;
        range = 1 << bit_size;
        /* modulo encoding */
        l= INT_BIT - 6 - bit_size;
        val = (val<<l)>>l;
        sign = val>>31;
        val= (val^sign)-sign;
        sign&=1;

        val--;
        code = (val >> bit_size) + 1;
        bits = val & (range - 1);

        put_bits(&s->pb, mvtab[code][1] + 1, (mvtab[code][0] << 1) | sign);
        if (bit_size > 0) {
            put_bits(&s->pb, bit_size, bits);
        }
    }
}

/* Encode MV differences on H.263+ with Unrestricted MV mode */
static void h263p_encode_umotion(MpegEncContext * s, int val)
{
    short sval = 0;
    short i = 0;
    short n_bits = 0;
    short temp_val;
    int code = 0;
    int tcode;

    if ( val == 0)
        put_bits(&s->pb, 1, 1);
    else if (val == 1)
        put_bits(&s->pb, 3, 0);
    else if (val == -1)
        put_bits(&s->pb, 3, 2);
    else {

        sval = ((val < 0) ? (short)(-val):(short)val);
        temp_val = sval;

        while (temp_val != 0) {
            temp_val = temp_val >> 1;
            n_bits++;
        }

        i = n_bits - 1;
        while (i > 0) {
            tcode = (sval & (1 << (i-1))) >> (i-1);
            tcode = (tcode << 1) | 1;
            code = (code << 2) | tcode;
            i--;
        }
        code = ((code << 1) | (val < 0)) << 1;
        put_bits(&s->pb, (2*n_bits)+1, code);
        //printf("\nVal = %d\tCode = %d", sval, code);
    }
}

static void init_mv_penalty_and_fcode(MpegEncContext *s)
{
    int f_code;
    int mv;

    for(f_code=1; f_code<=MAX_FCODE; f_code++){
        for(mv=-MAX_MV; mv<=MAX_MV; mv++){
            int len;

            if(mv==0) len= mvtab[0][1];
            else{
                int val, bit_size, range, code;

                bit_size = f_code - 1;
                range = 1 << bit_size;

                val=mv;
                if (val < 0)
                    val = -val;
                val--;
                code = (val >> bit_size) + 1;
                if(code<33){
                    len= mvtab[code][1] + 1 + bit_size;
                }else{
                    len= mvtab[32][1] + av_log2(code>>5) + 2 + bit_size;
                }
            }

            mv_penalty[f_code][mv+MAX_MV]= len;
        }
    }

    for(f_code=MAX_FCODE; f_code>0; f_code--){
        for(mv=-(16<<f_code); mv<(16<<f_code); mv++){
            fcode_tab[mv+MAX_MV]= f_code;
        }
    }

    for(mv=0; mv<MAX_MV*2+1; mv++){
        umv_fcode_tab[mv]= 1;
    }
}

static void init_uni_dc_tab(void)
{
    int level, uni_code, uni_len;

    for(level=-256; level<256; level++){
        int size, v, l;
        /* find number of bits */
        size = 0;
        v = abs(level);
        while (v) {
            v >>= 1;
            size++;
        }

        if (level < 0)
            l= (-level) ^ ((1 << size) - 1);
        else
            l= level;

        /* luminance */
        uni_code= DCtab_lum[size][0];
        uni_len = DCtab_lum[size][1];

        if (size > 0) {
            uni_code<<=size; uni_code|=l;
            uni_len+=size;
            if (size > 8){
                uni_code<<=1; uni_code|=1;
                uni_len++;
            }
        }
        uni_DCtab_lum_bits[level+256]= uni_code;
        uni_DCtab_lum_len [level+256]= uni_len;

        /* chrominance */
        uni_code= DCtab_chrom[size][0];
        uni_len = DCtab_chrom[size][1];

        if (size > 0) {
            uni_code<<=size; uni_code|=l;
            uni_len+=size;
            if (size > 8){
                uni_code<<=1; uni_code|=1;
                uni_len++;
            }
        }
        uni_DCtab_chrom_bits[level+256]= uni_code;
        uni_DCtab_chrom_len [level+256]= uni_len;

    }
}

static void init_uni_mpeg4_rl_tab(RLTable *rl, uint32_t *bits_tab, uint8_t *len_tab){
    int slevel, run, last;

    assert(MAX_LEVEL >= 64);
    assert(MAX_RUN   >= 63);

    for(slevel=-64; slevel<64; slevel++){
        if(slevel==0) continue;
        for(run=0; run<64; run++){
            for(last=0; last<=1; last++){
                const int index= UNI_