libavcodec/ac3enc.c:1841: error: Uninitialized Value
  The value read from ch0 was never initialized.

libavcodec/ac3enc.c:1841:5: 
1839. {
1840.     int ch, i, baie, bnd, got_cpl;
1841.     int av_uninit(ch0);
          ^
1842.     AC3Block *block = &s->blocks[blk];
1843. 

static void output_audio_block(AC3EncodeContext *s, int blk)
{
    int ch, i, baie, bnd, got_cpl;
    int av_uninit(ch0);
    AC3Block *block = &s->blocks[blk];
    for (ch = 0; ch < s->fbw_channels; ch++)
        put_bits(&s->pb, 1, 0);
    for (ch = 0; ch < s->fbw_channels; ch++)
        put_bits(&s->pb, 1, 1);
    put_bits(&s->pb, 1, 0);
    put_bits(&s->pb, 1, block->new_cpl_strategy);
    if (block->new_cpl_strategy) {
        put_bits(&s->pb, 1, block->cpl_in_use);
        if (block->cpl_in_use) {
            int start_sub, end_sub;
            for (ch = 1; ch <= s->fbw_channels; ch++)
                put_bits(&s->pb, 1, block->channel_in_cpl[ch]);
            if (s->channel_mode == AC3_CHMODE_STEREO)
                put_bits(&s->pb, 1, 0);
            start_sub = (s->start_freq[CPL_CH] - 37) / 12;
            end_sub   = (s->cpl_end_freq       - 37) / 12;
            put_bits(&s->pb, 4, start_sub);
            put_bits(&s->pb, 4, end_sub - 3);
            for (bnd = start_sub+1; bnd < end_sub; bnd++)
                put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);
        }
    }
    if (block->cpl_in_use) {
        for (ch = 1; ch <= s->fbw_channels; ch++) {
            if (block->channel_in_cpl[ch]) {
                put_bits(&s->pb, 1, block->new_cpl_coords);
                if (block->new_cpl_coords) {
                    put_bits(&s->pb, 2, block->cpl_master_exp[ch]);
                    for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
                        put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);
                        put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);
                    }
                }
            }
        }
    }
    if (s->channel_mode == AC3_CHMODE_STEREO) {
        put_bits(&s->pb, 1, block->new_rematrixing_strategy);
        if (block->new_rematrixing_strategy) {
            for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)
                put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);
        }
    }
    for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)
        put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
    if (s->lfe_on)
        put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
    for (ch = 1; ch <= s->fbw_channels; ch++) {
        if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])
            put_bits(&s->pb, 6, s->bandwidth_code);
    }
    for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
        int nb_groups;
        int cpl = (ch == CPL_CH);
        if (s->exp_strategy[ch][blk] == EXP_REUSE)
            continue;
        put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);
        nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];
        for (i = 1; i <= nb_groups; i++)
            put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
        if (ch != s->lfe_channel && !cpl)
            put_bits(&s->pb, 2, 0);
    }
    baie = (blk == 0);
    put_bits(&s->pb, 1, baie);
    if (baie) {
        put_bits(&s->pb, 2, s->slow_decay_code);
        put_bits(&s->pb, 2, s->fast_decay_code);
        put_bits(&s->pb, 2, s->slow_gain_code);
        put_bits(&s->pb, 2, s->db_per_bit_code);
        put_bits(&s->pb, 3, s->floor_code);
    }
    put_bits(&s->pb, 1, block->new_snr_offsets);
    if (block->new_snr_offsets) {
        put_bits(&s->pb, 6, s->coarse_snr_offset);
        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
            put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
            put_bits(&s->pb, 3, s->fast_gain_code[ch]);
        }
    }
    if (block->cpl_in_use) {
        put_bits(&s->pb, 1, block->new_cpl_leak);
        if (block->new_cpl_leak) {
            put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);
            put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);
        }
    }
    put_bits(&s->pb, 1, 0);
    put_bits(&s->pb, 1, 0);
    got_cpl = !block->cpl_in_use;
    for (ch = 1; ch <= s->channels; ch++) {
        int b, q;
        AC3Block *ref_block;
        if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
            ch0     = ch - 1;
            ch      = CPL_CH;
            got_cpl = 1;
        }
        ref_block = block->exp_ref_block[ch];
        for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) {
            q = block->qmant[ch][i];
            b = ref_block->bap[ch][i];
            switch (b) {
            case 0:                                         break;
            case 1: if (q != 128) put_bits(&s->pb,   5, q); break;
            case 2: if (q != 128) put_bits(&s->pb,   7, q); break;
            case 3:               put_bits(&s->pb,   3, q); break;
            case 4: if (q != 128) put_bits(&s->pb,   7, q); break;
            case 14:              put_bits(&s->pb,  14, q); break;
            case 15:              put_bits(&s->pb,  16, q); break;
            default:              put_bits(&s->pb, b-1, q); break;
            }
        }
        if (ch == CPL_CH)
            ch = ch0;
    }
}
['static void output_audio_block(AC3EncodeContext *s, int blk)\n{\n    int ch, i, baie, bnd, got_cpl;\n    int av_uninit(ch0);\n    AC3Block *block = &s->blocks[blk];\n    for (ch = 0; ch < s->fbw_channels; ch++)\n        put_bits(&s->pb, 1, 0);\n    for (ch = 0; ch < s->fbw_channels; ch++)\n        put_bits(&s->pb, 1, 1);\n    put_bits(&s->pb, 1, 0);\n    put_bits(&s->pb, 1, block->new_cpl_strategy);\n    if (block->new_cpl_strategy) {\n        put_bits(&s->pb, 1, block->cpl_in_use);\n        if (block->cpl_in_use) {\n            int start_sub, end_sub;\n            for (ch = 1; ch <= s->fbw_channels; ch++)\n                put_bits(&s->pb, 1, block->channel_in_cpl[ch]);\n            if (s->channel_mode == AC3_CHMODE_STEREO)\n                put_bits(&s->pb, 1, 0);\n            start_sub = (s->start_freq[CPL_CH] - 37) / 12;\n            end_sub   = (s->cpl_end_freq       - 37) / 12;\n            put_bits(&s->pb, 4, start_sub);\n            put_bits(&s->pb, 4, end_sub - 3);\n            for (bnd = start_sub+1; bnd < end_sub; bnd++)\n                put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);\n        }\n    }\n    if (block->cpl_in_use) {\n        for (ch = 1; ch <= s->fbw_channels; ch++) {\n            if (block->channel_in_cpl[ch]) {\n                put_bits(&s->pb, 1, block->new_cpl_coords);\n                if (block->new_cpl_coords) {\n                    put_bits(&s->pb, 2, block->cpl_master_exp[ch]);\n                    for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {\n                        put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);\n                        put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);\n                    }\n                }\n            }\n        }\n    }\n    if (s->channel_mode == AC3_CHMODE_STEREO) {\n        put_bits(&s->pb, 1, block->new_rematrixing_strategy);\n        if (block->new_rematrixing_strategy) {\n            for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)\n                put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);\n        }\n    }\n    for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)\n        put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);\n    if (s->lfe_on)\n        put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);\n    for (ch = 1; ch <= s->fbw_channels; ch++) {\n        if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])\n            put_bits(&s->pb, 6, s->bandwidth_code);\n    }\n    for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {\n        int nb_groups;\n        int cpl = (ch == CPL_CH);\n        if (s->exp_strategy[ch][blk] == EXP_REUSE)\n            continue;\n        put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);\n        nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];\n        for (i = 1; i <= nb_groups; i++)\n            put_bits(&s->pb, 7, block->grouped_exp[ch][i]);\n        if (ch != s->lfe_channel && !cpl)\n            put_bits(&s->pb, 2, 0);\n    }\n    baie = (blk == 0);\n    put_bits(&s->pb, 1, baie);\n    if (baie) {\n        put_bits(&s->pb, 2, s->slow_decay_code);\n        put_bits(&s->pb, 2, s->fast_decay_code);\n        put_bits(&s->pb, 2, s->slow_gain_code);\n        put_bits(&s->pb, 2, s->db_per_bit_code);\n        put_bits(&s->pb, 3, s->floor_code);\n    }\n    put_bits(&s->pb, 1, block->new_snr_offsets);\n    if (block->new_snr_offsets) {\n        put_bits(&s->pb, 6, s->coarse_snr_offset);\n        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {\n            put_bits(&s->pb, 4, s->fine_snr_offset[ch]);\n            put_bits(&s->pb, 3, s->fast_gain_code[ch]);\n        }\n    }\n    if (block->cpl_in_use) {\n        put_bits(&s->pb, 1, block->new_cpl_leak);\n        if (block->new_cpl_leak) {\n            put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);\n            put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);\n        }\n    }\n    put_bits(&s->pb, 1, 0);\n    put_bits(&s->pb, 1, 0);\n    got_cpl = !block->cpl_in_use;\n    for (ch = 1; ch <= s->channels; ch++) {\n        int b, q;\n        AC3Block *ref_block;\n        if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {\n            ch0     = ch - 1;\n            ch      = CPL_CH;\n            got_cpl = 1;\n        }\n        ref_block = block->exp_ref_block[ch];\n        for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) {\n            q = block->qmant[ch][i];\n            b = ref_block->bap[ch][i];\n            switch (b) {\n            case 0:                                         break;\n            case 1: if (q != 128) put_bits(&s->pb,   5, q); break;\n            case 2: if (q != 128) put_bits(&s->pb,   7, q); break;\n            case 3:               put_bits(&s->pb,   3, q); break;\n            case 4: if (q != 128) put_bits(&s->pb,   7, q); break;\n            case 14:              put_bits(&s->pb,  14, q); break;\n            case 15:              put_bits(&s->pb,  16, q); break;\n            default:              put_bits(&s->pb, b-1, q); break;\n            }\n        }\n        if (ch == CPL_CH)\n            ch = ch0;\n    }\n}']