Function msmpeg4v34_decode_mb

libavcodec/msmpeg4dec.c:216–306

}

static int msmpeg4v34_decode_mb(H263DecContext *const h)
{
    MSMP4DecContext *const ms = mpv_to_msmpeg4(h);
    int cbp, code, i;
    uint8_t *coded_val;
    uint32_t * const mb_type_ptr = &h->c.cur_pic.mb_type[h->c.mb_x + h->c.mb_y*h->c.mb_stride];

    if (get_bits_left(&h->gb) <= 0)
        return AVERROR_INVALIDDATA;

    if (h->c.pict_type == AV_PICTURE_TYPE_P) {
        if (ms->use_skip_mb_code) {
            if (get_bits1(&h->gb)) {
                /* skip mb */
                h->c.mb_intra = 0;
                for(i=0;i<6;i++)
                    h->c.block_last_index[i] = -1;
                h->c.mv_dir = MV_DIR_FORWARD;
                h->c.mv_type = MV_TYPE_16X16;
                h->c.mv[0][0][0] = 0;
                h->c.mv[0][0][1] = 0;
                h->c.mb_skipped  = 1;
                *mb_type_ptr = MB_TYPE_SKIP | MB_TYPE_FORWARD_MV | MB_TYPE_16x16;

                return 0;
            }
        }

        code = get_vlc2(&h->gb, ff_mb_non_intra_vlc[DEFAULT_INTER_INDEX], MB_NON_INTRA_VLC_BITS, 3);
        //h->c.mb_intra = (code & 0x40) ? 0 : 1;
        h->c.mb_intra = (~code & 0x40) >> 6;

        cbp = code & 0x3f;
    } else {
        h->c.mb_intra = 1;
        code = get_vlc2(&h->gb, ff_msmp4_mb_i_vlc, MSMP4_MB_INTRA_VLC_BITS, 2);
        /* predict coded block pattern */
        cbp = 0;
        for(i=0;i<6;i++) {
            int val = ((code >> (5 - i)) & 1);
            if (i < 4) {
                int pred = ff_msmpeg4_coded_block_pred(&h->c, i, &coded_val);
                val = val ^ pred;
                *coded_val = val;
            }
            cbp |= val << (5 - i);
        }
    }

    if (!h->c.mb_intra) {
        int mx, my;
        if (ms->per_mb_rl_table && cbp) {
            ms->rl_table_index = decode012(&h->gb);
            ms->rl_chroma_table_index = ms->rl_table_index;
        }
        ff_h263_pred_motion(&h->c, 0, 0, &mx, &my);
        ff_msmpeg4_decode_motion(ms, &mx, &my);
        h->c.mv_dir  = MV_DIR_FORWARD;