libavcodec/vc1_block.c:1488: error: Uninitialized Value
  The value read from is_intra[_] was never initialized.

libavcodec/vc1_block.c:1488:17: 
1486.                 if (i == 4)
1487.                     ff_vc1_mc_4mv_chroma(v, 0);
1488.                 v->mb_type[0][s->block_index[i]] = is_intra[i];
                      ^
1489.                 if (!coded_inter)
1490.                     coded_inter = !is_intra[i] & is_coded[i];

static int vc1_decode_p_mb(VC1Context *v)
{
    MpegEncContext *s = &v->s;
    GetBitContext *gb = &s->gb;
    int i, j;
    int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
    int cbp;
    int mqdiff, mquant;
    int ttmb = v->ttfrm;
    int mb_has_coeffs = 1;
    int dmv_x, dmv_y;
    int index, index1;
    int val, sign;
    int first_block = 1;
    int dst_idx, off;
    int skipped, fourmv;
    int block_cbp = 0, pat, block_tt = 0, block_intra = 0;
    mquant = v->pq;
    if (v->mv_type_is_raw)
        fourmv = get_bits1(gb);
    else
        fourmv = v->mv_type_mb_plane[mb_pos];
    if (v->skip_is_raw)
        skipped = get_bits1(gb);
    else
        skipped = v->s.mbskip_table[mb_pos];
    if (!fourmv) {
        if (!skipped) {
            GET_MVDATA(dmv_x, dmv_y);
            if (s->mb_intra) {
                s->current_picture.motion_val[1][s->block_index[0]][0] = 0;
                s->current_picture.motion_val[1][s->block_index[0]][1] = 0;
            }
            s->current_picture.mb_type[mb_pos] = s->mb_intra ? MB_TYPE_INTRA : MB_TYPE_16x16;
            ff_vc1_pred_mv(v, 0, dmv_x, dmv_y, 1, v->range_x, v->range_y, v->mb_type[0], 0, 0);
            if (s->mb_intra && !mb_has_coeffs) {
                GET_MQUANT();
                s->ac_pred = get_bits1(gb);
                cbp        = 0;
            } else if (mb_has_coeffs) {
                if (s->mb_intra)
                    s->ac_pred = get_bits1(gb);
                cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);
                GET_MQUANT();
            } else {
                mquant = v->pq;
                cbp    = 0;
            }
            s->current_picture.qscale_table[mb_pos] = mquant;
            if (!v->ttmbf && !s->mb_intra && mb_has_coeffs)
                ttmb = get_vlc2(gb, ff_vc1_ttmb_vlc[v->tt_index].table,
                                VC1_TTMB_VLC_BITS, 2);
            if (!s->mb_intra) ff_vc1_mc_1mv(v, 0);
            dst_idx = 0;
            for (i = 0; i < 6; i++) {
                s->dc_val[0][s->block_index[i]] = 0;
                dst_idx += i >> 2;
                val = ((cbp >> (5 - i)) & 1);
                off = (i & 4) ? 0 : ((i & 1) * 8 + (i & 2) * 4 * s->linesize);
                v->mb_type[0][s->block_index[i]] = s->mb_intra;
                if (s->mb_intra) {
                    v->a_avail = v->c_avail = 0;
                    if (i == 2 || i == 3 || !s->first_slice_line)
                        v->a_avail = v->mb_type[0][s->block_index[i] - s->block_wrap[i]];
                    if (i == 1 || i == 3 || s->mb_x)
                        v->c_avail = v->mb_type[0][s->block_index[i] - 1];
                    vc1_decode_intra_block(v, s->block[i], i, val, mquant,
                                           (i & 4) ? v->codingset2 : v->codingset);
                    if ((i>3) && (s->flags & CODEC_FLAG_GRAY))
                        continue;
                    v->vc1dsp.vc1_inv_trans_8x8(s->block[i]);
                    if (v->rangeredfrm)
                        for (j = 0; j < 64; j++)
                            s->block[i][j] <<= 1;
                    s->idsp.put_signed_pixels_clamped(s->block[i],
                                                      s->dest[dst_idx] + off,
                                                      i & 4 ? s->uvlinesize
                                                            : s->linesize);
                    if (v->pq >= 9 && v->overlap) {
                        if (v->c_avail)
                            v->vc1dsp.vc1_h_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);
                        if (v->a_avail)
                            v->vc1dsp.vc1_v_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);
                    }
                    block_cbp   |= 0xF << (i << 2);
                    block_intra |= 1 << i;
                } else if (val) {
                    pat = vc1_decode_p_block(v, s->block[i], i, mquant, ttmb, first_block,
                                             s->dest[dst_idx] + off, (i & 4) ? s->uvlinesize : s->linesize,
                                             (i & 4) && (s->flags & CODEC_FLAG_GRAY), &block_tt);
                    block_cbp |= pat << (i << 2);
                    if (!v->ttmbf && ttmb < 8)
                        ttmb = -1;
                    first_block = 0;
                }
            }
        } else {
            s->mb_intra = 0;
            for (i = 0; i < 6; i++) {
                v->mb_type[0][s->block_index[i]] = 0;
                s->dc_val[0][s->block_index[i]]  = 0;
            }
            s->current_picture.mb_type[mb_pos]      = MB_TYPE_SKIP;
            s->current_picture.qscale_table[mb_pos] = 0;
            ff_vc1_pred_mv(v, 0, 0, 0, 1, v->range_x, v->range_y, v->mb_type[0], 0, 0);
            ff_vc1_mc_1mv(v, 0);
        }
    } else {
        if (!skipped  ) {
            int intra_count = 0, coded_inter = 0;
            int is_intra[6], is_coded[6];
            cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);
            for (i = 0; i < 6; i++) {
                val = ((cbp >> (5 - i)) & 1);
                s->dc_val[0][s->block_index[i]] = 0;
                s->mb_intra                     = 0;
                if (i < 4) {
                    dmv_x = dmv_y = 0;
                    s->mb_intra   = 0;
                    mb_has_coeffs = 0;
                    if (val) {
                        GET_MVDATA(dmv_x, dmv_y);
                    }
                    ff_vc1_pred_mv(v, i, dmv_x, dmv_y, 0, v->range_x, v->range_y, v->mb_type[0], 0, 0);
                    if (!s->mb_intra)
                        ff_vc1_mc_4mv_luma(v, i, 0, 0);
                    intra_count += s->mb_intra;
                    is_intra[i]  = s->mb_intra;
                    is_coded[i]  = mb_has_coeffs;
                }
                if (i & 4) {
                    is_intra[i] = (intra_count >= 3);
                    is_coded[i] = val;
                }
                if (i == 4)
                    ff_vc1_mc_4mv_chroma(v, 0);
                v->mb_type[0][s->block_index[i]] = is_intra[i];
                if (!coded_inter)
                    coded_inter = !is_intra[i] & is_coded[i];
            }
            dst_idx = 0;
            if (!intra_count && !coded_inter)
                goto end;
            GET_MQUANT();
            s->current_picture.qscale_table[mb_pos] = mquant;
            {
                int intrapred = 0;
                for (i = 0; i < 6; i++)
                    if (is_intra[i]) {
                        if (((!s->first_slice_line || (i == 2 || i == 3)) && v->mb_type[0][s->block_index[i] - s->block_wrap[i]])
                            || ((s->mb_x || (i == 1 || i == 3)) && v->mb_type[0][s->block_index[i] - 1])) {
                            intrapred = 1;
                            break;
                        }
                    }
                if (intrapred)
                    s->ac_pred = get_bits1(gb);
                else
                    s->ac_pred = 0;
            }
            if (!v->ttmbf && coded_inter)
                ttmb = get_vlc2(gb, ff_vc1_ttmb_vlc[v->tt_index].table, VC1_TTMB_VLC_BITS, 2);
            for (i = 0; i < 6; i++) {
                dst_idx    += i >> 2;
                off         = (i & 4) ? 0 : ((i & 1) * 8 + (i & 2) * 4 * s->linesize);
                s->mb_intra = is_intra[i];
                if (is_intra[i]) {
                    v->a_avail = v->c_avail = 0;
                    if (i == 2 || i == 3 || !s->first_slice_line)
                        v->a_avail = v->mb_type[0][s->block_index[i] - s->block_wrap[i]];
                    if (i == 1 || i == 3 || s->mb_x)
                        v->c_avail = v->mb_type[0][s->block_index[i] - 1];
                    vc1_decode_intra_block(v, s->block[i], i, is_coded[i], mquant,
                                           (i & 4) ? v->codingset2 : v->codingset);
                    if ((i>3) && (s->flags & CODEC_FLAG_GRAY))
                        continue;
                    v->vc1dsp.vc1_inv_trans_8x8(s->block[i]);
                    if (v->rangeredfrm)
                        for (j = 0; j < 64; j++)
                            s->block[i][j] <<= 1;
                    s->idsp.put_signed_pixels_clamped(s->block[i],
                                                      s->dest[dst_idx] + off,
                                                      (i & 4) ? s->uvlinesize
                                                              : s->linesize);
                    if (v->pq >= 9 && v->overlap) {
                        if (v->c_avail)
                            v->vc1dsp.vc1_h_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);
                        if (v->a_avail)
                            v->vc1dsp.vc1_v_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);
                    }
                    block_cbp   |= 0xF << (i << 2);
                    block_intra |= 1 << i;
                } else if (is_coded[i]) {
                    pat = vc1_decode_p_block(v, s->block[i], i, mquant, ttmb,
                                             first_block, s->dest[dst_idx] + off,
                                             (i & 4) ? s->uvlinesize : s->linesize,
                                             (i & 4) && (s->flags & CODEC_FLAG_GRAY),
                                             &block_tt);
                    block_cbp |= pat << (i << 2);
                    if (!v->ttmbf && ttmb < 8)
                        ttmb = -1;
                    first_block = 0;
                }
            }
        } else {
            s->mb_intra                               = 0;
            s->current_picture.qscale_table[mb_pos] = 0;
            for (i = 0; i < 6; i++) {
                v->mb_type[0][s->block_index[i]] = 0;
                s->dc_val[0][s->block_index[i]]  = 0;
            }
            for (i = 0; i < 4; i++) {
                ff_vc1_pred_mv(v, i, 0, 0, 0, v->range_x, v->range_y, v->mb_type[0], 0, 0);
                ff_vc1_mc_4mv_luma(v, i, 0, 0);
            }
            ff_vc1_mc_4mv_chroma(v, 0);
            s->current_picture.qscale_table[mb_pos] = 0;
        }
    }
end:
    v->cbp[s->mb_x]      = block_cbp;
    v->ttblk[s->mb_x]    = block_tt;
    v->is_intra[s->mb_x] = block_intra;
    return 0;
}
['static int vc1_decode_p_mb(VC1Context *v)\n{\n    MpegEncContext *s = &v->s;\n    GetBitContext *gb = &s->gb;\n    int i, j;\n    int mb_pos = s->mb_x + s->mb_y * s->mb_stride;\n    int cbp;\n    int mqdiff, mquant;\n    int ttmb = v->ttfrm;\n    int mb_has_coeffs = 1;\n    int dmv_x, dmv_y;\n    int index, index1;\n    int val, sign;\n    int first_block = 1;\n    int dst_idx, off;\n    int skipped, fourmv;\n    int block_cbp = 0, pat, block_tt = 0, block_intra = 0;\n    mquant = v->pq;\n    if (v->mv_type_is_raw)\n        fourmv = get_bits1(gb);\n    else\n        fourmv = v->mv_type_mb_plane[mb_pos];\n    if (v->skip_is_raw)\n        skipped = get_bits1(gb);\n    else\n        skipped = v->s.mbskip_table[mb_pos];\n    if (!fourmv) {\n        if (!skipped) {\n            GET_MVDATA(dmv_x, dmv_y);\n            if (s->mb_intra) {\n                s->current_picture.motion_val[1][s->block_index[0]][0] = 0;\n                s->current_picture.motion_val[1][s->block_index[0]][1] = 0;\n            }\n            s->current_picture.mb_type[mb_pos] = s->mb_intra ? MB_TYPE_INTRA : MB_TYPE_16x16;\n            ff_vc1_pred_mv(v, 0, dmv_x, dmv_y, 1, v->range_x, v->range_y, v->mb_type[0], 0, 0);\n            if (s->mb_intra && !mb_has_coeffs) {\n                GET_MQUANT();\n                s->ac_pred = get_bits1(gb);\n                cbp        = 0;\n            } else if (mb_has_coeffs) {\n                if (s->mb_intra)\n                    s->ac_pred = get_bits1(gb);\n                cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);\n                GET_MQUANT();\n            } else {\n                mquant = v->pq;\n                cbp    = 0;\n            }\n            s->current_picture.qscale_table[mb_pos] = mquant;\n            if (!v->ttmbf && !s->mb_intra && mb_has_coeffs)\n                ttmb = get_vlc2(gb, ff_vc1_ttmb_vlc[v->tt_index].table,\n                                VC1_TTMB_VLC_BITS, 2);\n            if (!s->mb_intra) ff_vc1_mc_1mv(v, 0);\n            dst_idx = 0;\n            for (i = 0; i < 6; i++) {\n                s->dc_val[0][s->block_index[i]] = 0;\n                dst_idx += i >> 2;\n                val = ((cbp >> (5 - i)) & 1);\n                off = (i & 4) ? 0 : ((i & 1) * 8 + (i & 2) * 4 * s->linesize);\n                v->mb_type[0][s->block_index[i]] = s->mb_intra;\n                if (s->mb_intra) {\n                    v->a_avail = v->c_avail = 0;\n                    if (i == 2 || i == 3 || !s->first_slice_line)\n                        v->a_avail = v->mb_type[0][s->block_index[i] - s->block_wrap[i]];\n                    if (i == 1 || i == 3 || s->mb_x)\n                        v->c_avail = v->mb_type[0][s->block_index[i] - 1];\n                    vc1_decode_intra_block(v, s->block[i], i, val, mquant,\n                                           (i & 4) ? v->codingset2 : v->codingset);\n                    if ((i>3) && (s->flags & CODEC_FLAG_GRAY))\n                        continue;\n                    v->vc1dsp.vc1_inv_trans_8x8(s->block[i]);\n                    if (v->rangeredfrm)\n                        for (j = 0; j < 64; j++)\n                            s->block[i][j] <<= 1;\n                    s->idsp.put_signed_pixels_clamped(s->block[i],\n                                                      s->dest[dst_idx] + off,\n                                                      i & 4 ? s->uvlinesize\n                                                            : s->linesize);\n                    if (v->pq >= 9 && v->overlap) {\n                        if (v->c_avail)\n                            v->vc1dsp.vc1_h_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);\n                        if (v->a_avail)\n                            v->vc1dsp.vc1_v_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);\n                    }\n                    block_cbp   |= 0xF << (i << 2);\n                    block_intra |= 1 << i;\n                } else if (val) {\n                    pat = vc1_decode_p_block(v, s->block[i], i, mquant, ttmb, first_block,\n                                             s->dest[dst_idx] + off, (i & 4) ? s->uvlinesize : s->linesize,\n                                             (i & 4) && (s->flags & CODEC_FLAG_GRAY), &block_tt);\n                    block_cbp |= pat << (i << 2);\n                    if (!v->ttmbf && ttmb < 8)\n                        ttmb = -1;\n                    first_block = 0;\n                }\n            }\n        } else {\n            s->mb_intra = 0;\n            for (i = 0; i < 6; i++) {\n                v->mb_type[0][s->block_index[i]] = 0;\n                s->dc_val[0][s->block_index[i]]  = 0;\n            }\n            s->current_picture.mb_type[mb_pos]      = MB_TYPE_SKIP;\n            s->current_picture.qscale_table[mb_pos] = 0;\n            ff_vc1_pred_mv(v, 0, 0, 0, 1, v->range_x, v->range_y, v->mb_type[0], 0, 0);\n            ff_vc1_mc_1mv(v, 0);\n        }\n    } else {\n        if (!skipped  ) {\n            int intra_count = 0, coded_inter = 0;\n            int is_intra[6], is_coded[6];\n            cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);\n            for (i = 0; i < 6; i++) {\n                val = ((cbp >> (5 - i)) & 1);\n                s->dc_val[0][s->block_index[i]] = 0;\n                s->mb_intra                     = 0;\n                if (i < 4) {\n                    dmv_x = dmv_y = 0;\n                    s->mb_intra   = 0;\n                    mb_has_coeffs = 0;\n                    if (val) {\n                        GET_MVDATA(dmv_x, dmv_y);\n                    }\n                    ff_vc1_pred_mv(v, i, dmv_x, dmv_y, 0, v->range_x, v->range_y, v->mb_type[0], 0, 0);\n                    if (!s->mb_intra)\n                        ff_vc1_mc_4mv_luma(v, i, 0, 0);\n                    intra_count += s->mb_intra;\n                    is_intra[i]  = s->mb_intra;\n                    is_coded[i]  = mb_has_coeffs;\n                }\n                if (i & 4) {\n                    is_intra[i] = (intra_count >= 3);\n                    is_coded[i] = val;\n                }\n                if (i == 4)\n                    ff_vc1_mc_4mv_chroma(v, 0);\n                v->mb_type[0][s->block_index[i]] = is_intra[i];\n                if (!coded_inter)\n                    coded_inter = !is_intra[i] & is_coded[i];\n            }\n            dst_idx = 0;\n            if (!intra_count && !coded_inter)\n                goto end;\n            GET_MQUANT();\n            s->current_picture.qscale_table[mb_pos] = mquant;\n            {\n                int intrapred = 0;\n                for (i = 0; i < 6; i++)\n                    if (is_intra[i]) {\n                        if (((!s->first_slice_line || (i == 2 || i == 3)) && v->mb_type[0][s->block_index[i] - s->block_wrap[i]])\n                            || ((s->mb_x || (i == 1 || i == 3)) && v->mb_type[0][s->block_index[i] - 1])) {\n                            intrapred = 1;\n                            break;\n                        }\n                    }\n                if (intrapred)\n                    s->ac_pred = get_bits1(gb);\n                else\n                    s->ac_pred = 0;\n            }\n            if (!v->ttmbf && coded_inter)\n                ttmb = get_vlc2(gb, ff_vc1_ttmb_vlc[v->tt_index].table, VC1_TTMB_VLC_BITS, 2);\n            for (i = 0; i < 6; i++) {\n                dst_idx    += i >> 2;\n                off         = (i & 4) ? 0 : ((i & 1) * 8 + (i & 2) * 4 * s->linesize);\n                s->mb_intra = is_intra[i];\n                if (is_intra[i]) {\n                    v->a_avail = v->c_avail = 0;\n                    if (i == 2 || i == 3 || !s->first_slice_line)\n                        v->a_avail = v->mb_type[0][s->block_index[i] - s->block_wrap[i]];\n                    if (i == 1 || i == 3 || s->mb_x)\n                        v->c_avail = v->mb_type[0][s->block_index[i] - 1];\n                    vc1_decode_intra_block(v, s->block[i], i, is_coded[i], mquant,\n                                           (i & 4) ? v->codingset2 : v->codingset);\n                    if ((i>3) && (s->flags & CODEC_FLAG_GRAY))\n                        continue;\n                    v->vc1dsp.vc1_inv_trans_8x8(s->block[i]);\n                    if (v->rangeredfrm)\n                        for (j = 0; j < 64; j++)\n                            s->block[i][j] <<= 1;\n                    s->idsp.put_signed_pixels_clamped(s->block[i],\n                                                      s->dest[dst_idx] + off,\n                                                      (i & 4) ? s->uvlinesize\n                                                              : s->linesize);\n                    if (v->pq >= 9 && v->overlap) {\n                        if (v->c_avail)\n                            v->vc1dsp.vc1_h_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);\n                        if (v->a_avail)\n                            v->vc1dsp.vc1_v_overlap(s->dest[dst_idx] + off, i & 4 ? s->uvlinesize : s->linesize);\n                    }\n                    block_cbp   |= 0xF << (i << 2);\n                    block_intra |= 1 << i;\n                } else if (is_coded[i]) {\n                    pat = vc1_decode_p_block(v, s->block[i], i, mquant, ttmb,\n                                             first_block, s->dest[dst_idx] + off,\n                                             (i & 4) ? s->uvlinesize : s->linesize,\n                                             (i & 4) && (s->flags & CODEC_FLAG_GRAY),\n                                             &block_tt);\n                    block_cbp |= pat << (i << 2);\n                    if (!v->ttmbf && ttmb < 8)\n                        ttmb = -1;\n                    first_block = 0;\n                }\n            }\n        } else {\n            s->mb_intra                               = 0;\n            s->current_picture.qscale_table[mb_pos] = 0;\n            for (i = 0; i < 6; i++) {\n                v->mb_type[0][s->block_index[i]] = 0;\n                s->dc_val[0][s->block_index[i]]  = 0;\n            }\n            for (i = 0; i < 4; i++) {\n                ff_vc1_pred_mv(v, i, 0, 0, 0, v->range_x, v->range_y, v->mb_type[0], 0, 0);\n                ff_vc1_mc_4mv_luma(v, i, 0, 0);\n            }\n            ff_vc1_mc_4mv_chroma(v, 0);\n            s->current_picture.qscale_table[mb_pos] = 0;\n        }\n    }\nend:\n    v->cbp[s->mb_x]      = block_cbp;\n    v->ttblk[s->mb_x]    = block_tt;\n    v->is_intra[s->mb_x] = block_intra;\n    return 0;\n}']