PeerStreamer

/**

 * @file vorbis.c

 * Vorbis I decoder

 * @author Denes Balatoni  ( dbalatoni programozo hu )

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 *

 */

#undef V_DEBUG

#include <math.h>

#define ALT_BITSTREAM_READER_LE

#include "avcodec.h"

#include "bitstream.h"

#include "dsputil.h"

#include "vorbis.h"

#define V_NB_BITS 8

#define V_NB_BITS2 11

#define V_MAX_VLCS (1<<16)

#ifndef V_DEBUG

#define AV_DEBUG(...)

#endif

#undef NDEBUG

#include <assert.h>

/* Helper functions */

/**

 *  reads 0-32 bits when using the ALT_BITSTREAM_READER_LE bitstream reader

 */

unsigned int get_bits_long_le(GetBitContext *s, int n){

    if(n<=17) return get_bits(s, n);

    else{

        int ret= get_bits(s, 16);

        return ret | (get_bits(s, n-16) << 16);

    }

}

#define ilog(i) av_log2(2*(i))

static unsigned int nth_root(unsigned int x, unsigned int n) {   // x^(1/n)

    unsigned int ret=0, i, j;

    do {

        ++ret;

        for(i=0,j=ret;i<n-1;i++) j*=ret;

    } while (j<=x);

    return (ret-1);

}

static float vorbisfloat2float(uint_fast32_t val) {

    double mant=val&0x1fffff;

    long exp=(val&0x7fe00000L)>>21;

    if (val&0x80000000) mant=-mant;

    return(ldexp(mant, exp-20-768));

}

// Generate vlc codes from vorbis huffman code lengths

static int vorbis_len2vlc(vorbis_context *vc, uint_fast8_t *bits, uint_fast32_t *codes, uint_fast32_t num) {

    uint_fast32_t exit_at_level[33]={404,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

    uint_fast8_t i,j;

    uint_fast32_t code,p;

#ifdef V_DEBUG

    GetBitContext gb;

#endif

    for(p=0;(bits[p]==0) && (p<num);++p);

    if (p==num) {

//        av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");

        return 0;

    }

    codes[p]=0;

    for(i=0;i<bits[p];++i) {

        exit_at_level[i+1]=1<<i;

    }

#ifdef V_DEBUG

    av_log(vc->avccontext, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]);

    init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);

    for(i=0;i<bits[p];++i) {

        av_log(vc->avccontext, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");

    }

    av_log(vc->avccontext, AV_LOG_INFO, "\n");

#endif

    ++p;

    for(;p<num;++p) {

        if (bits[p]==0) continue;

        // find corresponding exit(node which the tree can grow further from)

        for(i=bits[p];i>0;--i) {

            if (exit_at_level[i]) break;

        }

        if (!i) return 1; // overspecified tree

        code=exit_at_level[i];

        exit_at_level[i]=0;

        // construct code (append 0s to end) and introduce new exits

        for(j=i+1;j<=bits[p];++j) {

            exit_at_level[j]=code+(1<<(j-1));

        }

        codes[p]=code;

#ifdef V_DEBUG

        av_log(vc->avccontext, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);

        init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);

        for(i=0;i<bits[p];++i) {

            av_log(vc->avccontext, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");

        }

        av_log(vc->avccontext, AV_LOG_INFO, "\n");

#endif

    }

    //FIXME no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)

    return 0;

}

// Free all allocated memory -----------------------------------------

static void vorbis_free(vorbis_context *vc) {

    int_fast16_t i;

    av_freep(&vc->channel_residues);

    av_freep(&vc->channel_floors);

    av_freep(&vc->saved);

    av_freep(&vc->ret);

    av_freep(&vc->buf);

    av_freep(&vc->buf_tmp);

    av_freep(&vc->residues);

    av_freep(&vc->modes);

    ff_mdct_end(&vc->mdct0);

    ff_mdct_end(&vc->mdct1);

    for(i=0;i<vc->codebook_count;++i) {

        av_free(vc->codebooks[i].codevectors);

        free_vlc(&vc->codebooks[i].vlc);

    }

    av_freep(&vc->codebooks);

    for(i=0;i<vc->floor_count;++i) {

        av_free(vc->floors[i].x_list);

        av_free(vc->floors[i].x_list_order);

        av_free(vc->floors[i].low_neighbour);

        av_free(vc->floors[i].high_neighbour);

    }

    av_freep(&vc->floors);

    for(i=0;i<vc->mapping_count;++i) {

        av_free(vc->mappings[i].magnitude);

        av_free(vc->mappings[i].angle);

        av_free(vc->mappings[i].mux);

    }

    av_freep(&vc->mappings);

}

// Parse setup header -------------------------------------------------

// Process codebooks part

static int vorbis_parse_setup_hdr_codebooks(vorbis_context *vc) {

    uint_fast16_t cb;

    uint_fast8_t *tmp_vlc_bits;

    uint_fast32_t *tmp_vlc_codes;

    GetBitContext *gb=&vc->gb;

    vc->codebook_count=get_bits(gb,8)+1;

    AV_DEBUG(" Codebooks: %d \n", vc->codebook_count);

    vc->codebooks=(vorbis_codebook *)av_mallocz(vc->codebook_count * sizeof(vorbis_codebook));

    tmp_vlc_bits=(uint_fast8_t *)av_mallocz(V_MAX_VLCS * sizeof(uint_fast8_t));

    tmp_vlc_codes=(uint_fast32_t *)av_mallocz(V_MAX_VLCS * sizeof(uint_fast32_t));

    for(cb=0;cb<vc->codebook_count;++cb) {

        vorbis_codebook *codebook_setup=&vc->codebooks[cb];

        uint_fast8_t ordered;

        uint_fast32_t t, used_entries=0;

        uint_fast32_t entries;

        AV_DEBUG(" %d. Codebook \n", cb);

        if (get_bits(gb, 24)!=0x564342) {

            av_log(vc->avccontext, AV_LOG_ERROR, " %"PRIdFAST16". Codebook setup data corrupt. \n", cb);

            goto error;

        }

        codebook_setup->dimensions=get_bits(gb, 16);

        if (codebook_setup->dimensions>16) {

            av_log(vc->avccontext, AV_LOG_ERROR, " %"PRIdFAST16". Codebook's dimension is too large (%d). \n", cb, codebook_setup->dimensions);

            goto error;

        }

        entries=get_bits(gb, 24);

        if (entries>V_MAX_VLCS) {

            av_log(vc->avccontext, AV_LOG_ERROR, " %"PRIdFAST16". Codebook has too many entries (%"PRIdFAST32"). \n", cb, entries);

            goto error;

        }

        ordered=get_bits1(gb);

        AV_DEBUG(" codebook_dimensions %d, codebook_entries %d \n", codebook_setup->dimensions, entries);

        if (!ordered) {

            uint_fast16_t ce;

            uint_fast8_t flag;

            uint_fast8_t sparse=get_bits1(gb);

            AV_DEBUG(" not ordered \n");

            if (sparse) {

                AV_DEBUG(" sparse \n");

                used_entries=0;

                for(ce=0;ce<entries;++ce) {

                    flag=get_bits1(gb);

                    if (flag) {

                        tmp_vlc_bits[ce]=get_bits(gb, 5)+1;

                        ++used_entries;

                    }

                    else tmp_vlc_bits[ce]=0;

                }

            } else {

                AV_DEBUG(" not sparse \n");

                used_entries=entries;

                for(ce=0;ce<entries;++ce) {

                    tmp_vlc_bits[ce]=get_bits(gb, 5)+1;

                }

            }

        } else {

            uint_fast16_t current_entry=0;

            uint_fast8_t current_length=get_bits(gb, 5)+1;

            AV_DEBUG(" ordered, current length: %d \n", current_length);  //FIXME

            used_entries=entries;

            for(;current_entry<used_entries;++current_length) {

                uint_fast16_t i, number;

                AV_DEBUG(" number bits: %d ", ilog(entries - current_entry));

                number=get_bits(gb, ilog(entries - current_entry));

                AV_DEBUG(" number: %d \n", number);

                for(i=current_entry;i<number+current_entry;++i) {

                    if (i<used_entries) tmp_vlc_bits[i]=current_length;

                }

                current_entry+=number;

            }

            if (current_entry>used_entries) {

                av_log(vc->avccontext, AV_LOG_ERROR, " More codelengths than codes in codebook. \n");

                goto error;

            }

        }

        codebook_setup->lookup_type=get_bits(gb, 4);

        AV_DEBUG(" lookup type: %d : %s \n", codebook_setup->lookup_type, codebook_setup->lookup_type ? "vq" : "no lookup" );

// If the codebook is used for (inverse) VQ, calculate codevectors.

        if (codebook_setup->lookup_type==1) {

            uint_fast16_t i, j, k;

            uint_fast16_t codebook_lookup_values=nth_root(entries, codebook_setup->dimensions);

            uint_fast16_t codebook_multiplicands[codebook_lookup_values];

            float codebook_minimum_value=vorbisfloat2float(get_bits_long_le(gb, 32));

            float codebook_delta_value=vorbisfloat2float(get_bits_long_le(gb, 32));

            uint_fast8_t codebook_value_bits=get_bits(gb, 4)+1;

            uint_fast8_t codebook_sequence_p=get_bits1(gb);

            AV_DEBUG(" We expect %d numbers for building the codevectors. \n", codebook_lookup_values);

            AV_DEBUG("  delta %f minmum %f \n", codebook_delta_value, codebook_minimum_value);

            for(i=0;i<codebook_lookup_values;++i) {

                codebook_multiplicands[i]=get_bits(gb, codebook_value_bits);

                AV_DEBUG(" multiplicands*delta+minmum : %e \n", (float)codebook_multiplicands[i]*codebook_delta_value+codebook_minimum_value);

                AV_DEBUG(" multiplicand %d \n", codebook_multiplicands[i]);

            }

// Weed out unused vlcs and build codevector vector

            codebook_setup->codevectors=(float *)av_mallocz(used_entries*codebook_setup->dimensions * sizeof(float));

            for(j=0, i=0;i<entries;++i) {

                uint_fast8_t dim=codebook_setup->dimensions;

                if (tmp_vlc_bits[i]) {

                    float last=0.0;

                    uint_fast32_t lookup_offset=i;

#ifdef V_DEBUG

                    av_log(vc->avccontext, AV_LOG_INFO, "Lookup offset %d ,", i);

#endif

                    for(k=0;k<dim;++k) {

                        uint_fast32_t multiplicand_offset = lookup_offset % codebook_lookup_values;

                        codebook_setup->codevectors[j*dim+k]=codebook_multiplicands[multiplicand_offset]*codebook_delta_value+codebook_minimum_value+last;

                        if (codebook_sequence_p) {

                            last=codebook_setup->codevectors[j*dim+k];

                        }

                        lookup_offset/=codebook_lookup_values;

                    }

                    tmp_vlc_bits[j]=tmp_vlc_bits[i];

#ifdef V_DEBUG

                    av_log(vc->avccontext, AV_LOG_INFO, "real lookup offset %d, vector: ", j);

                    for(k=0;k<dim;++k) {

                        av_log(vc->avccontext, AV_LOG_INFO, " %f ", codebook_setup->codevectors[j*dim+k]);

                    }

                    av_log(vc->avccontext, AV_LOG_INFO, "\n");

#endif

                    ++j;

                }

            }

            if (j!=used_entries) {

                av_log(vc->avccontext, AV_LOG_ERROR, "Bug in codevector vector building code. \n");

                goto error;

            }

            entries=used_entries;

        }

        else if (codebook_setup->lookup_type>=2) {

            av_log(vc->avccontext, AV_LOG_ERROR, "Codebook lookup type not supported. \n");

            goto error;

        }

// Initialize VLC table

        if (vorbis_len2vlc(vc, tmp_vlc_bits, tmp_vlc_codes, entries)) {

            av_log(vc->avccontext, AV_LOG_ERROR, " Invalid code lengths while generating vlcs. \n");

            goto error;

        }

        codebook_setup->maxdepth=0;

        for(t=0;t<entries;++t)

            if (tmp_vlc_bits[t]>=codebook_setup->maxdepth) codebook_setup->maxdepth=tmp_vlc_bits[t];

        if(codebook_setup->maxdepth > 3*V_NB_BITS) codebook_setup->nb_bits=V_NB_BITS2;

        else                                       codebook_setup->nb_bits=V_NB_BITS;

        codebook_setup->maxdepth=(codebook_setup->maxdepth+codebook_setup->nb_bits-1)/codebook_setup->nb_bits;

        if (init_vlc(&codebook_setup->vlc, codebook_setup->nb_bits, entries, tmp_vlc_bits, sizeof(*tmp_vlc_bits), sizeof(*tmp_vlc_bits), tmp_vlc_codes, sizeof(*tmp_vlc_codes), sizeof(*tmp_vlc_codes), INIT_VLC_LE)) {

            av_log(vc->avccontext, AV_LOG_ERROR, " Error generating vlc tables. \n");

            goto error;

        }

    }

    av_free(tmp_vlc_bits);

    av_free(tmp_vlc_codes);

    return 0;

// Error:

error:

    av_free(tmp_vlc_bits);

    av_free(tmp_vlc_codes);

    return 1;

}

// Process time domain transforms part (unused in Vorbis I)

static int vorbis_parse_setup_hdr_tdtransforms(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    uint_fast8_t i;

    uint_fast8_t vorbis_time_count=get_bits(gb, 6)+1;

    for(i=0;i<vorbis_time_count;++i) {

        uint_fast16_t vorbis_tdtransform=get_bits(gb, 16);

        AV_DEBUG(" Vorbis time domain transform %d: %d \n", vorbis_time_count, vorbis_tdtransform);

        if (vorbis_tdtransform) {

            av_log(vc->avccontext, AV_LOG_ERROR, "Vorbis time domain transform data nonzero. \n");

            return 1;

        }

    }

    return 0;

}

// Process floors part - only floor type 1 is supported

static int vorbis_parse_setup_hdr_floors(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    uint_fast16_t i,j,k;

    vc->floor_count=get_bits(gb, 6)+1;

    vc->floors=(vorbis_floor *)av_mallocz(vc->floor_count * sizeof(vorbis_floor));

    for (i=0;i<vc->floor_count;++i) {

        vorbis_floor *floor_setup=&vc->floors[i];

        floor_setup->floor_type=get_bits(gb, 16);

        AV_DEBUG(" %d. floor type %d \n", i, floor_setup->floor_type);

        if (floor_setup->floor_type==1) {

            uint_fast8_t maximum_class=0;

            uint_fast8_t rangebits;

            uint_fast16_t floor1_values=2;

            floor_setup->partitions=get_bits(gb, 5);

            AV_DEBUG(" %d.floor: %d partitions \n", i, floor_setup->partitions);

            for(j=0;j<floor_setup->partitions;++j) {

                floor_setup->partition_class[j]=get_bits(gb, 4);

                if (floor_setup->partition_class[j]>maximum_class) maximum_class=floor_setup->partition_class[j];

                AV_DEBUG(" %d. floor %d partition class %d \n", i, j, floor_setup->partition_class[j]);

            }

            AV_DEBUG(" maximum class %d \n", maximum_class);

            floor_setup->maximum_class=maximum_class;

            for(j=0;j<=maximum_class;++j) {

                floor_setup->class_dimensions[j]=get_bits(gb, 3)+1;

                floor_setup->class_subclasses[j]=get_bits(gb, 2);

                AV_DEBUG(" %d floor %d class dim: %d subclasses %d \n", i, j, floor_setup->class_dimensions[j], floor_setup->class_subclasses[j]);

                if (floor_setup->class_subclasses[j]) {

                    floor_setup->class_masterbook[j]=get_bits(gb, 8);

                    AV_DEBUG("   masterbook: %d \n", floor_setup->class_masterbook[j]);

                }

                for(k=0;k<(1<<floor_setup->class_subclasses[j]);++k) {

                    floor_setup->subclass_books[j][k]=get_bits(gb, 8)-1;

                    AV_DEBUG("    book %d. : %d \n", k, floor_setup->subclass_books[j][k]);

                }

            }

            floor_setup->multiplier=get_bits(gb, 2)+1;

            floor_setup->x_list_dim=2;

            for(j=0;j<floor_setup->partitions;++j) {

                floor_setup->x_list_dim+=floor_setup->class_dimensions[floor_setup->partition_class[j]];

            }

            floor_setup->x_list=(uint_fast16_t *)av_mallocz(floor_setup->x_list_dim * sizeof(uint_fast16_t));

            floor_setup->x_list_order=(uint_fast16_t *)av_mallocz(floor_setup->x_list_dim * sizeof(uint_fast16_t));

            floor_setup->low_neighbour=(uint_fast16_t *)av_mallocz(floor_setup->x_list_dim * sizeof(uint_fast16_t));

            floor_setup->high_neighbour=(uint_fast16_t *)av_mallocz(floor_setup->x_list_dim * sizeof(uint_fast16_t));

            rangebits=get_bits(gb, 4);

            floor_setup->x_list[0] = 0;

            floor_setup->x_list[1] = (1<<rangebits);

            for(j=0;j<floor_setup->partitions;++j) {

                for(k=0;k<floor_setup->class_dimensions[floor_setup->partition_class[j]];++k,++floor1_values) {

                    floor_setup->x_list[floor1_values]=get_bits(gb, rangebits);

                    AV_DEBUG(" %d. floor1 Y coord. %d \n", floor1_values, floor_setup->x_list[floor1_values]);

                }

            }

// Precalculate order of x coordinates - needed for decode

            for(k=0;k<floor_setup->x_list_dim;++k) {

                floor_setup->x_list_order[k]=k;

            }

            for(k=0;k<floor_setup->x_list_dim-1;++k) {   // FIXME optimize sorting ?

                for(j=k+1;j<floor_setup->x_list_dim;++j) {

                    if(floor_setup->x_list[floor_setup->x_list_order[k]]>floor_setup->x_list[floor_setup->x_list_order[j]]) {

                        uint_fast16_t tmp=floor_setup->x_list_order[k];

                        floor_setup->x_list_order[k]=floor_setup->x_list_order[j];

                        floor_setup->x_list_order[j]=tmp;

                    }

                }

            }

// Precalculate low and high neighbours

            for(k=2;k<floor_setup->x_list_dim;++k) {

                floor_setup->low_neighbour[k]=0;

                floor_setup->high_neighbour[k]=1;  // correct according to SPEC requirements

                for (j=0;j<k;++j) {

                    if ((floor_setup->x_list[j]<floor_setup->x_list[k]) &&

                      (floor_setup->x_list[j]>floor_setup->x_list[floor_setup->low_neighbour[k]])) {

                        floor_setup->low_neighbour[k]=j;

                    }

                    if ((floor_setup->x_list[j]>floor_setup->x_list[k]) &&

                      (floor_setup->x_list[j]<floor_setup->x_list[floor_setup->high_neighbour[k]])) {

                        floor_setup->high_neighbour[k]=j;

                    }

                }

            }

        }

        else {

            av_log(vc->avccontext, AV_LOG_ERROR, "Only floor type 1 supported. \n");

            return 1;

        }

    }

    return 0;

}

// Process residues part

static int vorbis_parse_setup_hdr_residues(vorbis_context *vc){

    GetBitContext *gb=&vc->gb;

    uint_fast8_t i, j, k;

    vc->residue_count=get_bits(gb, 6)+1;

    vc->residues=(vorbis_residue *)av_mallocz(vc->residue_count * sizeof(vorbis_residue));

    AV_DEBUG(" There are %d residues. \n", vc->residue_count);

    for(i=0;i<vc->residue_count;++i) {

        vorbis_residue *res_setup=&vc->residues[i];

        uint_fast8_t cascade[64];

        uint_fast8_t high_bits;

        uint_fast8_t low_bits;

        res_setup->type=get_bits(gb, 16);

        AV_DEBUG(" %d. residue type %d \n", i, res_setup->type);

        res_setup->begin=get_bits(gb, 24);

        res_setup->end=get_bits(gb, 24);

        res_setup->partition_size=get_bits(gb, 24)+1;

        res_setup->classifications=get_bits(gb, 6)+1;

        res_setup->classbook=get_bits(gb, 8);

        AV_DEBUG("    begin %d end %d part.size %d classif.s %d classbook %d \n", res_setup->begin, res_setup->end, res_setup->partition_size,

          res_setup->classifications, res_setup->classbook);

        for(j=0;j<res_setup->classifications;++j) {

            high_bits=0;

            low_bits=get_bits(gb, 3);

            if (get_bits1(gb)) {

                high_bits=get_bits(gb, 5);

            }

            cascade[j]=(high_bits<<3)+low_bits;

            AV_DEBUG("     %d class casscade depth: %d \n", j, ilog(cascade[j]));

        }

        res_setup->maxpass=0;

        for(j=0;j<res_setup->classifications;++j) {

            for(k=0;k<8;++k) {

                if (cascade[j]&(1<<k)) {

                        res_setup->books[j][k]=get_bits(gb, 8);

                    AV_DEBUG("     %d class casscade depth %d book: %d \n", j, k, res_setup->books[j][k]);

                    if (k>res_setup->maxpass) {

                        res_setup->maxpass=k;

                    }

                } else {

                    res_setup->books[j][k]=-1;

                }

            }

        }

    }

    return 0;

}

// Process mappings part

static int vorbis_parse_setup_hdr_mappings(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    uint_fast8_t i, j;

    vc->mapping_count=get_bits(gb, 6)+1;

    vc->mappings=(vorbis_mapping *)av_mallocz(vc->mapping_count * sizeof(vorbis_mapping));

    AV_DEBUG(" There are %d mappings. \n", vc->mapping_count);

    for(i=0;i<vc->mapping_count;++i) {

        vorbis_mapping *mapping_setup=&vc->mappings[i];

        if (get_bits(gb, 16)) {

            av_log(vc->avccontext, AV_LOG_ERROR, "Other mappings than type 0 are not compliant with the Vorbis I specification. \n");

            return 1;

        }

        if (get_bits1(gb)) {

            mapping_setup->submaps=get_bits(gb, 4)+1;

        } else {

            mapping_setup->submaps=1;

        }

        if (get_bits1(gb)) {

            mapping_setup->coupling_steps=get_bits(gb, 8)+1;

            mapping_setup->magnitude=(uint_fast8_t *)av_mallocz(mapping_setup->coupling_steps * sizeof(uint_fast8_t));

            mapping_setup->angle=(uint_fast8_t *)av_mallocz(mapping_setup->coupling_steps * sizeof(uint_fast8_t));

            for(j=0;j<mapping_setup->coupling_steps;++j) {

                mapping_setup->magnitude[j]=get_bits(gb, ilog(vc->audio_channels-1));

                mapping_setup->angle[j]=get_bits(gb, ilog(vc->audio_channels-1));

                // FIXME: sanity checks

            }

        } else {

            mapping_setup->coupling_steps=0;

        }

        AV_DEBUG("   %d mapping coupling steps: %d \n", i, mapping_setup->coupling_steps);

        if(get_bits(gb, 2)) {

            av_log(vc->avccontext, AV_LOG_ERROR, "%d. mapping setup data invalid. \n", i);

            return 1; // following spec.

        }

        if (mapping_setup->submaps>1) {

            mapping_setup->mux=(uint_fast8_t *)av_mallocz(vc->audio_channels * sizeof(uint_fast8_t));

            for(j=0;j<vc->audio_channels;++j) {

                mapping_setup->mux[j]=get_bits(gb, 4);

            }

        }

        for(j=0;j<mapping_setup->submaps;++j) {

            get_bits(gb, 8); // FIXME check?

            mapping_setup->submap_floor[j]=get_bits(gb, 8);

            mapping_setup->submap_residue[j]=get_bits(gb, 8);

            AV_DEBUG("   %d mapping %d submap : floor %d, residue %d \n", i, j, mapping_setup->submap_floor[j], mapping_setup->submap_residue[j]);

        }

    }

    return 0;

}

// Process modes part

static int vorbis_parse_setup_hdr_modes(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    uint_fast8_t i;

    vc->mode_count=get_bits(gb, 6)+1;

    vc->modes=(vorbis_mode *)av_mallocz(vc->mode_count * sizeof(vorbis_mode));

    AV_DEBUG(" There are %d modes.\n", vc->mode_count);

    for(i=0;i<vc->mode_count;++i) {

        vorbis_mode *mode_setup=&vc->modes[i];

        mode_setup->blockflag=get_bits(gb, 1);

        mode_setup->windowtype=get_bits(gb, 16); //FIXME check

        mode_setup->transformtype=get_bits(gb, 16); //FIXME check

        mode_setup->mapping=get_bits(gb, 8); //FIXME check

        AV_DEBUG(" %d mode: blockflag %d, windowtype %d, transformtype %d, mapping %d \n", i, mode_setup->blockflag, mode_setup->windowtype, mode_setup->transformtype, mode_setup->mapping);

    }

    return 0;

}

// Process the whole setup header using the functions above

static int vorbis_parse_setup_hdr(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    if ((get_bits(gb, 8)!='v') || (get_bits(gb, 8)!='o') ||

    (get_bits(gb, 8)!='r') || (get_bits(gb, 8)!='b') ||

    (get_bits(gb, 8)!='i') || (get_bits(gb, 8)!='s')) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (no vorbis signature). \n");

        return 1;

    }

    if (vorbis_parse_setup_hdr_codebooks(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (codebooks). \n");

        return 2;

    }

    if (vorbis_parse_setup_hdr_tdtransforms(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (time domain transforms). \n");

        return 3;

    }

    if (vorbis_parse_setup_hdr_floors(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (floors). \n");

        return 4;

    }

    if (vorbis_parse_setup_hdr_residues(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (residues). \n");

        return 5;

    }

    if (vorbis_parse_setup_hdr_mappings(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (mappings). \n");

        return 6;

    }

    if (vorbis_parse_setup_hdr_modes(vc)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (modes). \n");

        return 7;

    }

    if (!get_bits1(gb)) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis setup header packet corrupt (framing flag). \n");

        return 8; // framing flag bit unset error

    }

    return 0;

}

// Process the identification header

static int vorbis_parse_id_hdr(vorbis_context *vc){

    GetBitContext *gb=&vc->gb;

    uint_fast8_t bl0, bl1;

    const float *vwin[8]={ vwin64, vwin128, vwin256, vwin512, vwin1024, vwin2048, vwin4096, vwin8192 };

    if ((get_bits(gb, 8)!='v') || (get_bits(gb, 8)!='o') ||

    (get_bits(gb, 8)!='r') || (get_bits(gb, 8)!='b') ||

    (get_bits(gb, 8)!='i') || (get_bits(gb, 8)!='s')) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis id header packet corrupt (no vorbis signature). \n");

        return 1;

    }

    vc->version=get_bits_long_le(gb, 32);    //FIXME check 0

    vc->audio_channels=get_bits(gb, 8);   //FIXME check >0

    vc->audio_samplerate=get_bits_long_le(gb, 32);   //FIXME check >0

    vc->bitrate_maximum=get_bits_long_le(gb, 32);

    vc->bitrate_nominal=get_bits_long_le(gb, 32);

    vc->bitrate_minimum=get_bits_long_le(gb, 32);

    bl0=get_bits(gb, 4);

    bl1=get_bits(gb, 4);

    vc->blocksize_0=(1<<bl0);

    vc->blocksize_1=(1<<bl1);

    if (bl0>13 || bl0<6 || bl1>13 || bl1<6) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis id header packet corrupt (illegal blocksize). \n");

        return 3;

    }

    vc->swin=vwin[bl0-6];

    vc->lwin=vwin[bl1-6];

    if ((get_bits1(gb)) == 0) {

        av_log(vc->avccontext, AV_LOG_ERROR, " Vorbis id header packet corrupt (framing flag not set). \n");

        return 2;

    }

    vc->channel_residues=(float *)av_malloc((vc->blocksize_1/2)*vc->audio_channels * sizeof(float));

    vc->channel_floors=(float *)av_malloc((vc->blocksize_1/2)*vc->audio_channels * sizeof(float));

    vc->saved=(float *)av_malloc((vc->blocksize_1/2)*vc->audio_channels * sizeof(float));

    vc->ret=(float *)av_malloc((vc->blocksize_1/2)*vc->audio_channels * sizeof(float));

    vc->buf=(float *)av_malloc(vc->blocksize_1 * sizeof(float));

    vc->buf_tmp=(float *)av_malloc(vc->blocksize_1 * sizeof(float));

    vc->saved_start=0;

    ff_mdct_init(&vc->mdct0, bl0, 1);

    ff_mdct_init(&vc->mdct1, bl1, 1);

    AV_DEBUG(" vorbis version %d \n audio_channels %d \n audio_samplerate %d \n bitrate_max %d \n bitrate_nom %d \n bitrate_min %d \n blk_0 %d blk_1 %d \n ",

            vc->version, vc->audio_channels, vc->audio_samplerate, vc->bitrate_maximum, vc->bitrate_nominal, vc->bitrate_minimum, vc->blocksize_0, vc->blocksize_1);

/*

    BLK=vc->blocksize_0;

    for(i=0;i<BLK/2;++i) {

        vc->swin[i]=sin(0.5*3.14159265358*(sin(((float)i+0.5)/(float)BLK*3.14159265358))*(sin(((float)i+0.5)/(float)BLK*3.14159265358)));

    }

*/

    return 0;

}

// Process the extradata using the functions above (identification header, setup header)

static int vorbis_decode_init(AVCodecContext *avccontext) {

    vorbis_context *vc = avccontext->priv_data ;

    uint8_t *headers = avccontext->extradata;

    int headers_len=avccontext->extradata_size;

    uint8_t *header_start[3];

    int header_len[3];

    GetBitContext *gb = &(vc->gb);

    int i, j, hdr_type;

    vc->avccontext = avccontext;

    if (!headers_len) {

        av_log(avccontext, AV_LOG_ERROR, "Extradata corrupt.\n");

        return -1;

    }

    if(headers[0] == 0 && headers[1] == 30) {

        for(i = 0; i < 3; i++){

            header_len[i] = *headers++ << 8;

            header_len[i] += *headers++;

            header_start[i] = headers;

            headers += header_len[i];

        }

    } else if(headers[0] == 2) {

        for(j=1,i=0;i<2;++i, ++j) {

            header_len[i]=0;

            while(j<headers_len && headers[j]==0xff) {

                header_len[i]+=0xff;

                ++j;

            }

            if (j>=headers_len) {

                av_log(avccontext, AV_LOG_ERROR, "Extradata corrupt.\n");

                return -1;

            }

            header_len[i]+=headers[j];

        }

        header_len[2]=headers_len-header_len[0]-header_len[1]-j;

        headers+=j;

        header_start[0] = headers;

        header_start[1] = header_start[0] + header_len[0];

        header_start[2] = header_start[1] + header_len[1];

    } else {

        av_log(avccontext, AV_LOG_ERROR, "Extradata corrupt.\n");

        return -1;

    }

    init_get_bits(gb, header_start[0], header_len[0]*8);

    hdr_type=get_bits(gb, 8);

    if (hdr_type!=1) {

        av_log(avccontext, AV_LOG_ERROR, "First header is not the id header.\n");

        return -1;

    }

    if (vorbis_parse_id_hdr(vc)) {

        av_log(avccontext, AV_LOG_ERROR, "Id header corrupt.\n");

        vorbis_free(vc);

        return -1;

    }

    init_get_bits(gb, header_start[2], header_len[2]*8);

    hdr_type=get_bits(gb, 8);

    if (hdr_type!=5) {

        av_log(avccontext, AV_LOG_ERROR, "Third header is not the setup header.\n");

        return -1;

    }

    if (vorbis_parse_setup_hdr(vc)) {

        av_log(avccontext, AV_LOG_ERROR, "Setup header corrupt.\n");

        vorbis_free(vc);

        return -1;

    }

    avccontext->channels = vc->audio_channels;

    avccontext->sample_rate = vc->audio_samplerate;

    return 0 ;

}

// Decode audiopackets -------------------------------------------------

// Read and decode floor (type 1 only)

static uint_fast8_t vorbis_floor1_decode(vorbis_context *vc, vorbis_floor *vf, float *vec) {

    GetBitContext *gb=&vc->gb;

    uint_fast16_t range_v[4]={ 256, 128, 86, 64 };

    uint_fast16_t range=range_v[vf->multiplier-1];

    uint_fast16_t floor1_Y[vf->x_list_dim];

    uint_fast16_t floor1_Y_final[vf->x_list_dim];

    uint_fast8_t floor1_flag[vf->x_list_dim];

    uint_fast8_t class_;

    uint_fast8_t cdim;

    uint_fast8_t cbits;

    uint_fast8_t csub;

    uint_fast8_t cval;

    int_fast16_t book;

    uint_fast16_t offset;

    uint_fast16_t i,j;

    uint_fast16_t *floor_x_sort=vf->x_list_order;

    /*u*/int_fast16_t adx, ady, off, predicted; // WTF ? dy/adx= (unsigned)dy/adx ?

    int_fast16_t dy, err;

    uint_fast16_t lx,hx, ly, hy=0;

    if (!get_bits1(gb)) return 1; // silence

// Read values (or differences) for the floor's points

    floor1_Y[0]=get_bits(gb, ilog(range-1));

    floor1_Y[1]=get_bits(gb, ilog(range-1));

    AV_DEBUG("floor 0 Y %d floor 1 Y %d \n", floor1_Y[0], floor1_Y[1]);

    offset=2;

    for(i=0;i<vf->partitions;++i) {

        class_=vf->partition_class[i];

        cdim=vf->class_dimensions[class_];

        cbits=vf->class_subclasses[class_];

        csub=(1<<cbits)-1;

        cval=0;

        AV_DEBUG("Cbits %d \n", cbits);

        if (cbits) { // this reads all subclasses for this partition's class

            cval=get_vlc2(gb, vc->codebooks[vf->class_masterbook[class_]].vlc.table,

            vc->codebooks[vf->class_masterbook[class_]].nb_bits, 3);

        }

        for(j=0;j<cdim;++j) {

            book=vf->subclass_books[class_][cval & csub];

            AV_DEBUG("book %d Cbits %d cval %d  bits:%d \n", book, cbits, cval, get_bits_count(gb));

            cval=cval>>cbits;

            if (book>0) {

                floor1_Y[offset+j]=get_vlc2(gb, vc->codebooks[book].vlc.table,

                vc->codebooks[book].nb_bits, 3);

            } else {

                floor1_Y[offset+j]=0;

            }

            AV_DEBUG(" floor(%d) = %d \n", vf->x_list[offset+j], floor1_Y[offset+j]);

        }

        offset+=cdim;

    }

// Amplitude calculation from the differences

    floor1_flag[0]=1;

    floor1_flag[1]=1;

    floor1_Y_final[0]=floor1_Y[0];

    floor1_Y_final[1]=floor1_Y[1];

    for(i=2;i<vf->x_list_dim;++i) {

        uint_fast16_t val, highroom, lowroom, room;

        uint_fast16_t high_neigh_offs;

        uint_fast16_t low_neigh_offs;

        low_neigh_offs=vf->low_neighbour[i];

        high_neigh_offs=vf->high_neighbour[i];

        dy=floor1_Y_final[high_neigh_offs]-floor1_Y_final[low_neigh_offs];  // render_point begin

        adx=vf->x_list[high_neigh_offs]-vf->x_list[low_neigh_offs];

        ady= ABS(dy);

        err=ady*(vf->x_list[i]-vf->x_list[low_neigh_offs]);

        off=err/adx;

        if (dy<0) {

            predicted=floor1_Y_final[low_neigh_offs]-off;

        } else {

            predicted=floor1_Y_final[low_neigh_offs]+off;

        } // render_point end

        val=floor1_Y[i];

        highroom=range-predicted;

        lowroom=predicted;

        if (highroom < lowroom) {

            room=highroom*2;

        } else {

            room=lowroom*2;   // SPEC mispelling

        }

        if (val) {

            floor1_flag[low_neigh_offs]=1;

            floor1_flag[high_neigh_offs]=1;

            floor1_flag[i]=1;

            if (val>=room) {

                if (highroom > lowroom) {

                    floor1_Y_final[i]=val-lowroom+predicted;

                } else {

                    floor1_Y_final[i]=predicted-val+highroom-1;

                }

            } else {

                if (val & 1) {

                    floor1_Y_final[i]=predicted-(val+1)/2;

                } else {

                    floor1_Y_final[i]=predicted+val/2;

                }

            }

        } else {

            floor1_flag[i]=0;

            floor1_Y_final[i]=predicted;

        }

        AV_DEBUG(" Decoded floor(%d) = %d / val %d \n", vf->x_list[i], floor1_Y_final[i], val);

    }

// Curve synth - connect the calculated dots and convert from dB scale FIXME optimize ?

    hx=0;

    lx=0;

    ly=floor1_Y_final[0]*vf->multiplier;  // conforms to SPEC

    vec[0]=floor1_inverse_db_table[ly];

    for(i=1;i<vf->x_list_dim;++i) {

        AV_DEBUG(" Looking at post %d \n", i);

        if (floor1_flag[floor_x_sort[i]]) {   // SPEC mispelled

            int_fast16_t x, y, dy, base, sy; // if uncommented: dy = -32 adx = 2  base = 2blablabla ?????

            hy=floor1_Y_final[floor_x_sort[i]]*vf->multiplier;

            hx=vf->x_list[floor_x_sort[i]];

            dy=hy-ly;

            adx=hx-lx;

            ady= (dy<0) ? -dy:dy;//ABS(dy);

            base=dy/adx;

            AV_DEBUG(" dy %d  adx %d base %d = %d \n", dy, adx, base, dy/adx);

            x=lx;

            y=ly;

            err=0;

            if (dy<0) {

                sy=base-1;

            } else {

                sy=base+1;

            }

            ady=ady-(base<0 ? -base : base)*adx;

            vec[x]=floor1_inverse_db_table[y];

            AV_DEBUG(" vec[ %d ] = %d \n", x, y);

            for(x=lx+1;(x<hx) && (x<vf->x_list[1]);++x) {

                err+=ady;

                if (err>=adx) {

                    err-=adx;

                    y+=sy;

                } else {

                    y+=base;

                }

                vec[x]=floor1_inverse_db_table[y];

                AV_DEBUG(" vec[ %d ] = %d \n", x, y);

            }

/*            for(j=1;j<hx-lx+1;++j) {  // iterating render_point

                dy=hy-ly;

                adx=hx-lx;

                ady= dy<0 ? -dy : dy;

                err=ady*j;

                off=err/adx;

                if (dy<0) {

                    predicted=ly-off;

                } else {

                    predicted=ly+off;

                }

                if (lx+j < vf->x_list[1]) {

                    vec[lx+j]=floor1_inverse_db_table[predicted];

                }

            }*/

            lx=hx;

            ly=hy;

        }

    }

    if (hx<vf->x_list[1]) {

        for(i=hx;i<vf->x_list[1];++i) {

            vec[i]=floor1_inverse_db_table[hy];

        }

    }

    AV_DEBUG(" Floor decoded\n");

    return 0;

}

// Read and decode residue

static int vorbis_residue_decode(vorbis_context *vc, vorbis_residue *vr, uint_fast8_t ch, uint_fast8_t *do_not_decode, float *vec, uint_fast16_t vlen) {

    GetBitContext *gb=&vc->gb;

    uint_fast8_t c_p_c=vc->codebooks[vr->classbook].dimensions;

    uint_fast16_t n_to_read=vr->end-vr->begin;

    uint_fast16_t ptns_to_read=n_to_read/vr->partition_size;

    uint_fast8_t classifs[ptns_to_read*vc->audio_channels];

    uint_fast8_t pass;

    uint_fast8_t ch_used;

    uint_fast8_t i,j,l;

    uint_fast16_t k;

    if (vr->type==2) {

        for(j=1;j<ch;++j) {

                do_not_decode[0]&=do_not_decode[j];  // FIXME - clobbering input

        }

        if (do_not_decode[0]) return 0;

        ch_used=1;

    } else {

        ch_used=ch;

    }

    AV_DEBUG(" residue type 0/1/2 decode begin, ch: %d  cpc %d  \n", ch, c_p_c);

    for(pass=0;pass<=vr->maxpass;++pass) { // FIXME OPTIMIZE?

        uint_fast16_t voffset;

        uint_fast16_t partition_count;

        uint_fast16_t j_times_ptns_to_read;

        voffset=vr->begin;

        for(partition_count=0;partition_count<ptns_to_read;) {  // SPEC        error

            if (!pass) {

                for(j_times_ptns_to_read=0, j=0;j<ch_used;++j) {

                    if (!do_not_decode[j]) {

                        uint_fast32_t temp=get_vlc2(gb, vc->codebooks[vr->classbook].vlc.table,

                        vc->codebooks[vr->classbook].nb_bits, 3);

                        AV_DEBUG("Classword: %d \n", temp);

                        assert(vr->classifications > 1 && vr->classifications<256 && temp<=65536); //needed for inverse[]

                        for(i=0;i<c_p_c;++i) {

                            uint_fast32_t temp2;

                            temp2=(((uint_fast64_t)temp) * inverse[vr->classifications])>>32;

                            classifs[j_times_ptns_to_read+partition_count+c_p_c-1-i]=temp-temp2*vr->classifications;

                            temp=temp2;

                        }

                    }

                    j_times_ptns_to_read+=ptns_to_read;

                }

            }

            for(i=0;(i<c_p_c) && (partition_count<ptns_to_read);++i) {

                for(j_times_ptns_to_read=0, j=0;j<ch_used;++j) {

                    uint_fast16_t voffs;

                    if (!do_not_decode[j]) {

                        uint_fast8_t vqclass=classifs[j_times_ptns_to_read+partition_count];

                        int_fast16_t vqbook=vr->books[vqclass][pass];

                        if (vqbook>=0) {

                            uint_fast16_t coffs;

                            uint_fast16_t step=vr->partition_size/vc->codebooks[vqbook].dimensions;

                            vorbis_codebook codebook= vc->codebooks[vqbook];

                            if (vr->type==0) {

                                voffs=voffset+j*vlen;

                                for(k=0;k<step;++k) {

                                    coffs=get_vlc2(gb, codebook.vlc.table, codebook.nb_bits, 3) * codebook.dimensions;

                                    for(l=0;l<codebook.dimensions;++l) {

                                        vec[voffs+k+l*step]+=codebook.codevectors[coffs+l];  // FPMATH

                                    }

                                }

                            }

                            else if (vr->type==1) {

                                voffs=voffset+j*vlen;

                                for(k=0;k<step;++k) {

                                    coffs=get_vlc2(gb, codebook.vlc.table, codebook.nb_bits, 3) * codebook.dimensions;

                                    for(l=0;l<codebook.dimensions;++l, ++voffs) {

                                        vec[voffs]+=codebook.codevectors[coffs+l];  // FPMATH

                                        AV_DEBUG(" pass %d offs: %d curr: %f change: %f cv offs.: %d  \n", pass, voffs, vec[voffs], codebook.codevectors[coffs+l], coffs);

                                    }

                                }

                            }

                            else if (vr->type==2 && ch==2 && (voffset&1)==0 && (codebook.dimensions&1)==0) { // most frequent case optimized

                                voffs=voffset>>1;

                                for(k=0;k<step;++k) {

                                    coffs=get_vlc2(gb, codebook.vlc.table, codebook.nb_bits, 3) * codebook.dimensions;

                                    for(l=0;l<codebook.dimensions;l+=2, voffs++) {

                                        vec[voffs     ]+=codebook.codevectors[coffs+l  ];  // FPMATH

                                        vec[voffs+vlen]+=codebook.codevectors[coffs+l+1];  // FPMATH

                                        AV_DEBUG(" pass %d offs: %d curr: %f change: %f cv offs.: %d+%d  \n", pass, voffset/ch+(voffs%ch)*vlen, vec[voffset/ch+(voffs%ch)*vlen], codebook.codevectors[coffs+l], coffs, l);

                                    }

                                }

                            }

                            else if (vr->type==2) {

                                voffs=voffset;

                                for(k=0;k<step;++k) {

                                    coffs=get_vlc2(gb, codebook.vlc.table, codebook.nb_bits, 3) * codebook.dimensions;

                                    for(l=0;l<codebook.dimensions;++l, ++voffs) {

                                        vec[voffs/ch+(voffs%ch)*vlen]+=codebook.codevectors[coffs+l];  // FPMATH FIXME use if and counter instead of / and %

                                        AV_DEBUG(" pass %d offs: %d curr: %f change: %f cv offs.: %d+%d  \n", pass, voffset/ch+(voffs%ch)*vlen, vec[voffset/ch+(voffs%ch)*vlen], codebook.codevectors[coffs+l], coffs, l);

                                    }

                                }

                            } else {

                                av_log(vc->avccontext, AV_LOG_ERROR, " Invalid residue type while residue decode?! \n");

                                return 1;

                            }

                        }

                    }

                    j_times_ptns_to_read+=ptns_to_read;

                }

                ++partition_count;

                voffset+=vr->partition_size;

            }

        }

    }

    return 0;

}

// Decode the audio packet using the functions above

#define BIAS 385

static int vorbis_parse_audio_packet(vorbis_context *vc) {

    GetBitContext *gb=&vc->gb;

    uint_fast8_t previous_window=0,next_window=0;

    uint_fast8_t mode_number;

    uint_fast16_t blocksize;

    int_fast32_t i,j;

    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;

    uint_fast16_t saved_start=0;

    if (get_bits1(gb)) {

        av_log(vc->avccontext, AV_LOG_ERROR, "Not a Vorbis I audio packet.\n");

        return -1; // packet type not audio

    }

    if (vc->mode_count==1) {

        mode_number=0;

    } else {

        mode_number=get_bits(gb, ilog(vc->mode_count-1));

    }

    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);

    if (vc->modes[mode_number].blockflag) {

        previous_window=get_bits1(gb);

        next_window=get_bits1(gb);

    }

    blocksize=vc->modes[mode_number].blockflag ? vc->blocksize_1 : vc->blocksize_0;

    memset(ch_res_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2); //FIXME can this be removed ?

    memset(ch_floor_ptr, 0, sizeof(float)*vc->audio_channels*blocksize/2); //FIXME can this be removed ?

// Decode floor(1)

    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]=vorbis_floor1_decode(vc, floor, ch_floor_ptr);

        ch_floor_ptr+=blocksize/2;

    }

// Nonzero vector propagate

    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;

        }

    }

// Decode residue

    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;

    }

// Inverse coupling

    for(i=mapping->coupling_steps-1;i>=0;--i) { //warning: i has to be signed

        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;

        for(j=0;j<blocksize/2;++j) {