static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquant, int ttmb, int first_block,
                              uint8_t *dst, int linesize, int skip_block)
{
    MpegEncContext *s = &v->s;
    GetBitContext *gb = &s->gb;
    int i, j;
    int subblkpat = 0;
    int scale, off, idx, last, skip, value;
    int ttblk = ttmb & 7;

    if(ttmb == -1) {
        ttblk = ff_vc1_ttblk_to_tt[v->tt_index][get_vlc2(gb, ff_vc1_ttblk_vlc[v->tt_index].table, VC1_TTBLK_VLC_BITS, 1)];
    }
    if(ttblk == TT_4X4) {
        subblkpat = ~(get_vlc2(gb, ff_vc1_subblkpat_vlc[v->tt_index].table, VC1_SUBBLKPAT_VLC_BITS, 1) + 1);
    }
    if((ttblk != TT_8X8 && ttblk != TT_4X4) && (v->ttmbf || (ttmb != -1 && (ttmb & 8) && !first_block))) {
        subblkpat = decode012(gb);
        if(subblkpat) subblkpat ^= 3; //swap decoded pattern bits
        if(ttblk == TT_8X4_TOP || ttblk == TT_8X4_BOTTOM) ttblk = TT_8X4;
        if(ttblk == TT_4X8_RIGHT || ttblk == TT_4X8_LEFT) ttblk = TT_4X8;
    }
    scale = 2 * mquant + ((v->pq == mquant) ? v->halfpq : 0);

    // convert transforms like 8X4_TOP to generic TT and SUBBLKPAT
    if(ttblk == TT_8X4_TOP || ttblk == TT_8X4_BOTTOM) {
        subblkpat = 2 - (ttblk == TT_8X4_TOP);
        ttblk = TT_8X4;
    }
    if(ttblk == TT_4X8_RIGHT || ttblk == TT_4X8_LEFT) {
        subblkpat = 2 - (ttblk == TT_4X8_LEFT);
        ttblk = TT_4X8;
    }
    switch(ttblk) {
    case TT_8X8:
        i = 0;
        last = 0;
        while (!last) {
            vc1_decode_ac_coeff(v, &last, &skip, &value, v->codingset2);
            i += skip;
            if(i > 63)
                break;
            idx = wmv1_scantable[0][i++];
            block[idx] = value * scale;
            if(!v->pquantizer)
                block[idx] += (block[idx] < 0) ? -mquant : mquant;
        }
        if(!skip_block){
            s->dsp.vc1_inv_trans_8x8(block);
            s->dsp.add_pixels_clamped(block, dst, linesize);
        }
        break;
    case TT_4X4:
        for(j = 0; j < 4; j++) {
            last = subblkpat & (1 << (3 - j));
            i = 0;
            off = (j & 1) * 4 + (j & 2) * 16;
            while (!last) {
                vc1_decode_ac_coeff(v, &last, &skip, &value, v->codingset2);
                i += skip;
                if(i > 15)
                    break;
                idx = ff_vc1_simple_progressive_4x4_zz[i++];
                block[idx + off] = value * scale;
                if(!v->pquantizer)
                    block[idx + off] += (block[idx + off] < 0) ? -mquant : mquant;
            }
            if(!(subblkpat & (1 << (3 - j))) && !skip_block)
                s->dsp.vc1_inv_trans_4x4(dst + (j&1)*4 + (j&2)*2*linesize, linesize, block + off);
        }
        break;
    case TT_8X4:
        for(j = 0; j < 2; j++) {
            last = subblkpat & (1 << (1 - j));
            i = 0;
            off = j * 32;
            while (!last) {
                vc1_decode_ac_coeff(v, &last, &skip, &value, v->codingset2);
                i += skip;
                if(i > 31)
                    break;
                idx = v->zz_8x4[i++]+off;
                block[idx] = value * scale;
                if(!v->pquantizer)
                    block[idx] += (block[idx] < 0) ? -mquant : mquant;
            }
            if(!(subblkpat & (1 << (1 - j))) && !skip_block)
                s->dsp.vc1_inv_trans_8x4(dst + j*4*linesize, linesize, block + off);
        }
        break;
    case TT_4X8:
        for(j = 0; j < 2; j++) {
            last = subblkpat & (1 << (1 - j));
            i = 0;
            off = j * 4;
            while (!last) {
                vc1_decode_ac_coeff(v, &last, &skip, &value, v->codingset2);
                i += skip;
                if(i > 31)
                    break;
                idx = v->zz_4x8[i++]+off;
                block[idx] = value * scale;
                if(!v->pquantizer)
                    block[idx] += (block[idx] < 0) ? -mquant : mquant;
            }
            if(!(subblkpat & (1 << (1 - j))) && !skip_block)
                s->dsp.vc1_inv_trans_4x8(dst + j*4, linesize, block + off);
        }
        break;
    }
    return 0;
}