libavcodec/vorbis_dec.c:1523: error: Uninitialized Value
  The value read from res_chan[_] was never initialized.

libavcodec/vorbis_dec.c:1523:9: 
1521.         uint_fast16_t bs0=vc->blocksize[0];
1522.         uint_fast16_t bs1=vc->blocksize[1];
1523.         float *residue=vc->channel_residues+res_chan[j]*blocksize/2;
              ^
1524.         float *floor=vc->channel_floors+j*blocksize/2;
1525.         float *saved=vc->saved+j*bs1/4;

static int vorbis_parse_audio_packet(vorbis_context *vc) {
    GetBitContext *gb=&vc->gb;
    uint_fast8_t previous_window=vc->previous_window;
    uint_fast8_t mode_number;
    uint_fast8_t blockflag;
    uint_fast16_t blocksize;
    int_fast32_t i,j,dir;
    uint_fast8_t no_residue[vc->audio_channels];
    uint_fast8_t do_not_decode[vc->audio_channels];
    vorbis_mapping *mapping;
    float *ch_res_ptr=vc->channel_residues;
    float *ch_floor_ptr=vc->channel_floors;
    uint_fast8_t res_chan[vc->audio_channels];
    uint_fast8_t res_num=0;
    int_fast16_t retlen=0;
    float fadd_bias = vc->add_bias;
    if (get_bits1(gb)) {
        av_log(vc->avccontext, AV_LOG_ERROR, "Not a Vorbis I audio packet.\n");
        return -1;
    }
    if (vc->mode_count==1) {
        mode_number=0;
    } else {
        mode_number=get_bits(gb, ilog(vc->mode_count-1));
    }
    vc->mode_number=mode_number;
    mapping=&vc->mappings[vc->modes[mode_number].mapping];
    AV_DEBUG(" Mode number: %d , mapping: %d , blocktype %d \n", mode_number, vc->modes[mode_number].mapping, vc->modes[mode_number].blockflag);
    blockflag=vc->modes[mode_number].blockflag;
    blocksize=vc->blocksize[blockflag];
    if (blockflag) {
        skip_bits(gb, 2);
    }
    memset(ch_res_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2);
    memset(ch_floor_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2);
    for(i=0;i<vc->audio_channels;++i) {
        vorbis_floor *floor;
        if (mapping->submaps>1) {
            floor=&vc->floors[mapping->submap_floor[mapping->mux[i]]];
        } else {
            floor=&vc->floors[mapping->submap_floor[0]];
        }
        no_residue[i]=floor->decode(vc, &floor->data, ch_floor_ptr);
        ch_floor_ptr+=blocksize/2;
    }
    for(i=mapping->coupling_steps-1;i>=0;--i) {
        if (!(no_residue[mapping->magnitude[i]] & no_residue[mapping->angle[i]])) {
            no_residue[mapping->magnitude[i]]=0;
            no_residue[mapping->angle[i]]=0;
        }
    }
    for(i=0;i<mapping->submaps;++i) {
        vorbis_residue *residue;
        uint_fast8_t ch=0;
        for(j=0;j<vc->audio_channels;++j) {
            if ((mapping->submaps==1) || (i=mapping->mux[j])) {
                res_chan[j]=res_num;
                if (no_residue[j]) {
                    do_not_decode[ch]=1;
                } else {
                    do_not_decode[ch]=0;
                }
                ++ch;
                ++res_num;
            }
        }
        residue=&vc->residues[mapping->submap_residue[i]];
        vorbis_residue_decode(vc, residue, ch, do_not_decode, ch_res_ptr, blocksize/2);
        ch_res_ptr+=ch*blocksize/2;
    }
    for(i=mapping->coupling_steps-1;i>=0;--i) {
        float *mag, *ang;
        mag=vc->channel_residues+res_chan[mapping->magnitude[i]]*blocksize/2;
        ang=vc->channel_residues+res_chan[mapping->angle[i]]*blocksize/2;
        vc->dsp.vorbis_inverse_coupling(mag, ang, blocksize/2);
    }
    for(j=0, ch_floor_ptr=vc->channel_floors;j<vc->audio_channels;++j,ch_floor_ptr+=blocksize/2) {
        ch_res_ptr=vc->channel_residues+res_chan[j]*blocksize/2;
        vc->dsp.vector_fmul(ch_floor_ptr, ch_res_ptr, blocksize/2);
    }
    retlen = (blocksize + vc->blocksize[previous_window])/4;
    dir = retlen <= blocksize/2;
    for(j=dir?0:vc->audio_channels-1; (unsigned)j<vc->audio_channels; j+=dir*2-1) {
        uint_fast16_t bs0=vc->blocksize[0];
        uint_fast16_t bs1=vc->blocksize[1];
        float *residue=vc->channel_residues+res_chan[j]*blocksize/2;
        float *floor=vc->channel_floors+j*blocksize/2;
        float *saved=vc->saved+j*bs1/4;
        float *ret=vc->channel_residues+j*retlen;
        float *buf=floor;
        const float *win=vc->win[blockflag&previous_window];
        vc->mdct[0].fft.imdct_half(&vc->mdct[blockflag], buf, floor, residue);
        if(blockflag == previous_window) {
            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, blocksize/4);
        } else if(blockflag > previous_window) {
            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, bs0/4);
            copy_normalize(ret+bs0/2, buf+bs0/4, (bs1-bs0)/4, vc->exp_bias, fadd_bias);
        } else {
            copy_normalize(ret, saved, (bs1-bs0)/4, vc->exp_bias, fadd_bias);
            vc->dsp.vector_fmul_window(ret+(bs1-bs0)/4, saved+(bs1-bs0)/4, buf, win, fadd_bias, bs0/4);
        }
        memcpy(saved, buf+blocksize/4, blocksize/4*sizeof(float));
    }
    vc->previous_window = blockflag;
    return retlen;
}
['static int vorbis_parse_audio_packet(vorbis_context *vc) {\n    GetBitContext *gb=&vc->gb;\n    uint_fast8_t previous_window=vc->previous_window;\n    uint_fast8_t mode_number;\n    uint_fast8_t blockflag;\n    uint_fast16_t blocksize;\n    int_fast32_t i,j,dir;\n    uint_fast8_t no_residue[vc->audio_channels];\n    uint_fast8_t do_not_decode[vc->audio_channels];\n    vorbis_mapping *mapping;\n    float *ch_res_ptr=vc->channel_residues;\n    float *ch_floor_ptr=vc->channel_floors;\n    uint_fast8_t res_chan[vc->audio_channels];\n    uint_fast8_t res_num=0;\n    int_fast16_t retlen=0;\n    float fadd_bias = vc->add_bias;\n    if (get_bits1(gb)) {\n        av_log(vc->avccontext, AV_LOG_ERROR, "Not a Vorbis I audio packet.\\n");\n        return -1;\n    }\n    if (vc->mode_count==1) {\n        mode_number=0;\n    } else {\n        mode_number=get_bits(gb, ilog(vc->mode_count-1));\n    }\n    vc->mode_number=mode_number;\n    mapping=&vc->mappings[vc->modes[mode_number].mapping];\n    AV_DEBUG(" Mode number: %d , mapping: %d , blocktype %d \\n", mode_number, vc->modes[mode_number].mapping, vc->modes[mode_number].blockflag);\n    blockflag=vc->modes[mode_number].blockflag;\n    blocksize=vc->blocksize[blockflag];\n    if (blockflag) {\n        skip_bits(gb, 2);\n    }\n    memset(ch_res_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2);\n    memset(ch_floor_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2);\n    for(i=0;i<vc->audio_channels;++i) {\n        vorbis_floor *floor;\n        if (mapping->submaps>1) {\n            floor=&vc->floors[mapping->submap_floor[mapping->mux[i]]];\n        } else {\n            floor=&vc->floors[mapping->submap_floor[0]];\n        }\n        no_residue[i]=floor->decode(vc, &floor->data, ch_floor_ptr);\n        ch_floor_ptr+=blocksize/2;\n    }\n    for(i=mapping->coupling_steps-1;i>=0;--i) {\n        if (!(no_residue[mapping->magnitude[i]] & no_residue[mapping->angle[i]])) {\n            no_residue[mapping->magnitude[i]]=0;\n            no_residue[mapping->angle[i]]=0;\n        }\n    }\n    for(i=0;i<mapping->submaps;++i) {\n        vorbis_residue *residue;\n        uint_fast8_t ch=0;\n        for(j=0;j<vc->audio_channels;++j) {\n            if ((mapping->submaps==1) || (i=mapping->mux[j])) {\n                res_chan[j]=res_num;\n                if (no_residue[j]) {\n                    do_not_decode[ch]=1;\n                } else {\n                    do_not_decode[ch]=0;\n                }\n                ++ch;\n                ++res_num;\n            }\n        }\n        residue=&vc->residues[mapping->submap_residue[i]];\n        vorbis_residue_decode(vc, residue, ch, do_not_decode, ch_res_ptr, blocksize/2);\n        ch_res_ptr+=ch*blocksize/2;\n    }\n    for(i=mapping->coupling_steps-1;i>=0;--i) {\n        float *mag, *ang;\n        mag=vc->channel_residues+res_chan[mapping->magnitude[i]]*blocksize/2;\n        ang=vc->channel_residues+res_chan[mapping->angle[i]]*blocksize/2;\n        vc->dsp.vorbis_inverse_coupling(mag, ang, blocksize/2);\n    }\n    for(j=0, ch_floor_ptr=vc->channel_floors;j<vc->audio_channels;++j,ch_floor_ptr+=blocksize/2) {\n        ch_res_ptr=vc->channel_residues+res_chan[j]*blocksize/2;\n        vc->dsp.vector_fmul(ch_floor_ptr, ch_res_ptr, blocksize/2);\n    }\n    retlen = (blocksize + vc->blocksize[previous_window])/4;\n    dir = retlen <= blocksize/2;\n    for(j=dir?0:vc->audio_channels-1; (unsigned)j<vc->audio_channels; j+=dir*2-1) {\n        uint_fast16_t bs0=vc->blocksize[0];\n        uint_fast16_t bs1=vc->blocksize[1];\n        float *residue=vc->channel_residues+res_chan[j]*blocksize/2;\n        float *floor=vc->channel_floors+j*blocksize/2;\n        float *saved=vc->saved+j*bs1/4;\n        float *ret=vc->channel_residues+j*retlen;\n        float *buf=floor;\n        const float *win=vc->win[blockflag&previous_window];\n        vc->mdct[0].fft.imdct_half(&vc->mdct[blockflag], buf, floor, residue);\n        if(blockflag == previous_window) {\n            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, blocksize/4);\n        } else if(blockflag > previous_window) {\n            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, bs0/4);\n            copy_normalize(ret+bs0/2, buf+bs0/4, (bs1-bs0)/4, vc->exp_bias, fadd_bias);\n        } else {\n            copy_normalize(ret, saved, (bs1-bs0)/4, vc->exp_bias, fadd_bias);\n            vc->dsp.vector_fmul_window(ret+(bs1-bs0)/4, saved+(bs1-bs0)/4, buf, win, fadd_bias, bs0/4);\n        }\n        memcpy(saved, buf+blocksize/4, blocksize/4*sizeof(float));\n    }\n    vc->previous_window = blockflag;\n    return retlen;\n}']