libavcodec/vc1.c:2538: error: Uninitialized Value
  The value read from i was never initialized.

libavcodec/vc1.c:2538:5: 
2536.         }
2537.     }
2538.     s->block_last_index[n] = i;
          ^
2539. 
2540.     return 0;

static int vc1_decode_i_block(VC1Context *v, DCTELEM block[64], int n, int coded, int codingset)
{
    GetBitContext *gb = &v->s.gb;
    MpegEncContext *s = &v->s;
    int dc_pred_dir = 0;
    int i;
    int16_t *dc_val;
    int16_t *ac_val, *ac_val2;
    int dcdiff;
    if (n < 4) {
        dcdiff = get_vlc2(&s->gb, ff_msmp4_dc_luma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);
    } else {
        dcdiff = get_vlc2(&s->gb, ff_msmp4_dc_chroma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);
    }
    if (dcdiff < 0){
        av_log(s->avctx, AV_LOG_ERROR, "Illegal DC VLC\n");
        return -1;
    }
    if (dcdiff)
    {
        if (dcdiff == 119  )
        {
            if (v->pq == 1) dcdiff = get_bits(gb, 10);
            else if (v->pq == 2) dcdiff = get_bits(gb, 9);
            else dcdiff = get_bits(gb, 8);
        }
        else
        {
            if (v->pq == 1)
                dcdiff = (dcdiff<<2) + get_bits(gb, 2) - 3;
            else if (v->pq == 2)
                dcdiff = (dcdiff<<1) + get_bits1(gb)   - 1;
        }
        if (get_bits1(gb))
            dcdiff = -dcdiff;
    }
    dcdiff += vc1_i_pred_dc(&v->s, v->overlap, v->pq, n, &dc_val, &dc_pred_dir);
    *dc_val = dcdiff;
    if (n < 4) {
        block[0] = dcdiff * s->y_dc_scale;
    } else {
        block[0] = dcdiff * s->c_dc_scale;
    }
    if (!coded) {
        goto not_coded;
    }
    i = 1;
    {
        int last = 0, skip, value;
        const int8_t *zz_table;
        int scale;
        int k;
        scale = v->pq * 2 + v->halfpq;
        if(v->s.ac_pred) {
            if(!dc_pred_dir)
                zz_table = wmv1_scantable[2];
            else
                zz_table = wmv1_scantable[3];
        } else
            zz_table = wmv1_scantable[1];
        ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
        ac_val2 = ac_val;
        if(dc_pred_dir)
            ac_val -= 16;
        else
            ac_val -= 16 * s->block_wrap[n];
        while (!last) {
            vc1_decode_ac_coeff(v, &last, &skip, &value, codingset);
            i += skip;
            if(i > 63)
                break;
            block[zz_table[i++]] = value;
        }
        if(s->ac_pred) {
            if(dc_pred_dir) {
                for(k = 1; k < 8; k++)
                    block[k << 3] += ac_val[k];
            } else {
                for(k = 1; k < 8; k++)
                    block[k] += ac_val[k + 8];
            }
        }
        for(k = 1; k < 8; k++) {
            ac_val2[k] = block[k << 3];
            ac_val2[k + 8] = block[k];
        }
        for(k = 1; k < 64; k++)
            if(block[k]) {
                block[k] *= scale;
                if(!v->pquantizer)
                    block[k] += (block[k] < 0) ? -v->pq : v->pq;
            }
        if(s->ac_pred) i = 63;
    }
not_coded:
    if(!coded) {
        int k, scale;
        ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
        ac_val2 = ac_val;
        i = 0;
        scale = v->pq * 2 + v->halfpq;
        memset(ac_val2, 0, 16 * 2);
        if(dc_pred_dir) {
            ac_val -= 16;
            if(s->ac_pred)
                memcpy(ac_val2, ac_val, 8 * 2);
        } else {
            ac_val -= 16 * s->block_wrap[n];
            if(s->ac_pred)
                memcpy(ac_val2 + 8, ac_val + 8, 8 * 2);
        }
        if(s->ac_pred) {
            if(dc_pred_dir) {
                for(k = 1; k < 8; k++) {
                    block[k << 3] = ac_val[k] * scale;
                    if(!v->pquantizer && block[k << 3])
                        block[k << 3] += (block[k << 3] < 0) ? -v->pq : v->pq;
                }
            } else {
                for(k = 1; k < 8; k++) {
                    block[k] = ac_val[k + 8] * scale;
                    if(!v->pquantizer && block[k])
                        block[k] += (block[k] < 0) ? -v->pq : v->pq;
                }
            }
            i = 63;
        }
    }
    s->block_last_index[n] = i;
    return 0;
}
['static int vc1_decode_i_block(VC1Context *v, DCTELEM block[64], int n, int coded, int codingset)\n{\n    GetBitContext *gb = &v->s.gb;\n    MpegEncContext *s = &v->s;\n    int dc_pred_dir = 0;\n    int i;\n    int16_t *dc_val;\n    int16_t *ac_val, *ac_val2;\n    int dcdiff;\n    if (n < 4) {\n        dcdiff = get_vlc2(&s->gb, ff_msmp4_dc_luma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);\n    } else {\n        dcdiff = get_vlc2(&s->gb, ff_msmp4_dc_chroma_vlc[s->dc_table_index].table, DC_VLC_BITS, 3);\n    }\n    if (dcdiff < 0){\n        av_log(s->avctx, AV_LOG_ERROR, "Illegal DC VLC\\n");\n        return -1;\n    }\n    if (dcdiff)\n    {\n        if (dcdiff == 119  )\n        {\n            if (v->pq == 1) dcdiff = get_bits(gb, 10);\n            else if (v->pq == 2) dcdiff = get_bits(gb, 9);\n            else dcdiff = get_bits(gb, 8);\n        }\n        else\n        {\n            if (v->pq == 1)\n                dcdiff = (dcdiff<<2) + get_bits(gb, 2) - 3;\n            else if (v->pq == 2)\n                dcdiff = (dcdiff<<1) + get_bits1(gb)   - 1;\n        }\n        if (get_bits1(gb))\n            dcdiff = -dcdiff;\n    }\n    dcdiff += vc1_i_pred_dc(&v->s, v->overlap, v->pq, n, &dc_val, &dc_pred_dir);\n    *dc_val = dcdiff;\n    if (n < 4) {\n        block[0] = dcdiff * s->y_dc_scale;\n    } else {\n        block[0] = dcdiff * s->c_dc_scale;\n    }\n    if (!coded) {\n        goto not_coded;\n    }\n    i = 1;\n    {\n        int last = 0, skip, value;\n        const int8_t *zz_table;\n        int scale;\n        int k;\n        scale = v->pq * 2 + v->halfpq;\n        if(v->s.ac_pred) {\n            if(!dc_pred_dir)\n                zz_table = wmv1_scantable[2];\n            else\n                zz_table = wmv1_scantable[3];\n        } else\n            zz_table = wmv1_scantable[1];\n        ac_val = s->ac_val[0][0] + s->block_index[n] * 16;\n        ac_val2 = ac_val;\n        if(dc_pred_dir)\n            ac_val -= 16;\n        else\n            ac_val -= 16 * s->block_wrap[n];\n        while (!last) {\n            vc1_decode_ac_coeff(v, &last, &skip, &value, codingset);\n            i += skip;\n            if(i > 63)\n                break;\n            block[zz_table[i++]] = value;\n        }\n        if(s->ac_pred) {\n            if(dc_pred_dir) {\n                for(k = 1; k < 8; k++)\n                    block[k << 3] += ac_val[k];\n            } else {\n                for(k = 1; k < 8; k++)\n                    block[k] += ac_val[k + 8];\n            }\n        }\n        for(k = 1; k < 8; k++) {\n            ac_val2[k] = block[k << 3];\n            ac_val2[k + 8] = block[k];\n        }\n        for(k = 1; k < 64; k++)\n            if(block[k]) {\n                block[k] *= scale;\n                if(!v->pquantizer)\n                    block[k] += (block[k] < 0) ? -v->pq : v->pq;\n            }\n        if(s->ac_pred) i = 63;\n    }\nnot_coded:\n    if(!coded) {\n        int k, scale;\n        ac_val = s->ac_val[0][0] + s->block_index[n] * 16;\n        ac_val2 = ac_val;\n        i = 0;\n        scale = v->pq * 2 + v->halfpq;\n        memset(ac_val2, 0, 16 * 2);\n        if(dc_pred_dir) {\n            ac_val -= 16;\n            if(s->ac_pred)\n                memcpy(ac_val2, ac_val, 8 * 2);\n        } else {\n            ac_val -= 16 * s->block_wrap[n];\n            if(s->ac_pred)\n                memcpy(ac_val2 + 8, ac_val + 8, 8 * 2);\n        }\n        if(s->ac_pred) {\n            if(dc_pred_dir) {\n                for(k = 1; k < 8; k++) {\n                    block[k << 3] = ac_val[k] * scale;\n                    if(!v->pquantizer && block[k << 3])\n                        block[k << 3] += (block[k << 3] < 0) ? -v->pq : v->pq;\n                }\n            } else {\n                for(k = 1; k < 8; k++) {\n                    block[k] = ac_val[k + 8] * scale;\n                    if(!v->pquantizer && block[k])\n                        block[k] += (block[k] < 0) ? -v->pq : v->pq;\n                }\n            }\n            i = 63;\n        }\n    }\n    s->block_last_index[n] = i;\n    return 0;\n}']