FFmpeg/libavcodec/vorbis_enc.c

/*
 * copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file libavcodec/vorbis_enc.c
 * Native Vorbis encoder.
 * @author Oded Shimon <ods15@ods15.dyndns.org>
 */

#include <float.h>
#include "avcodec.h"
#include "dsputil.h"
#include "vorbis.h"
#include "vorbis_enc_data.h"

#define BITSTREAM_WRITER_LE
#include "put_bits.h"

#undef NDEBUG
#include <assert.h>

typedef struct {
    int nentries;
    uint8_t *lens;
    uint32_t *codewords;
    int ndimentions;
    float min;
    float delta;
    int seq_p;
    int lookup;
    int *quantlist;
    float *dimentions;
    float *pow2;
} vorbis_enc_codebook;

typedef struct {
    int dim;
    int subclass;
    int masterbook;
    int *books;
} vorbis_enc_floor_class;

typedef struct {
    int partitions;
    int *partition_to_class;
    int nclasses;
    vorbis_enc_floor_class *classes;
    int multiplier;
    int rangebits;
    int values;
    vorbis_floor1_entry *list;
} vorbis_enc_floor;

typedef struct {
    int type;
    int begin;
    int end;
    int partition_size;
    int classifications;
    int classbook;
    int8_t (*books)[8];
    float (*maxes)[2];
} vorbis_enc_residue;

typedef struct {
    int submaps;
    int *mux;
    int *floor;
    int *residue;
    int coupling_steps;
    int *magnitude;
    int *angle;
} vorbis_enc_mapping;

typedef struct {
    int blockflag;
    int mapping;
} vorbis_enc_mode;

typedef struct {
    int channels;
    int sample_rate;
    int log2_blocksize[2];
    FFTContext mdct[2];
    const float *win[2];
    int have_saved;
    float *saved;
    float *samples;
    float *floor;  // also used for tmp values for mdct
    float *coeffs; // also used for residue after floor
    float quality;

    int ncodebooks;
    vorbis_enc_codebook *codebooks;

    int nfloors;
    vorbis_enc_floor *floors;

    int nresidues;
    vorbis_enc_residue *residues;

    int nmappings;
    vorbis_enc_mapping *mappings;

    int nmodes;
    vorbis_enc_mode *modes;

    int64_t sample_count;
} vorbis_enc_context;

static inline void put_codeword(PutBitContext *pb, vorbis_enc_codebook *cb,
                                int entry)
{
    assert(entry >= 0);
    assert(entry < cb->nentries);
    assert(cb->lens[entry]);
    put_bits(pb, cb->lens[entry], cb->codewords[entry]);
}

static int cb_lookup_vals(int lookup, int dimentions, int entries)
{
    if (lookup == 1)
        return ff_vorbis_nth_root(entries, dimentions);
    else if (lookup == 2)
        return dimentions *entries;
    return 0;
}

static void ready_codebook(vorbis_enc_codebook *cb)
{
    int i;

    ff_vorbis_len2vlc(cb->lens, cb->codewords, cb->nentries);

    if (!cb->lookup) {
        cb->pow2 = cb->dimentions = NULL;
    } else {
        int vals = cb_lookup_vals(cb->lookup, cb->ndimentions, cb->nentries);
        cb->dimentions = av_malloc(sizeof(float) * cb->nentries * cb->ndimentions);
        cb->pow2 = av_mallocz(sizeof(float) * cb->nentries);
        for (i = 0; i < cb->nentries; i++) {
            float last = 0;
            int j;
            int div = 1;
            for (j = 0; j < cb->ndimentions; j++) {
                int off;
                if (cb->lookup == 1)
                    off = (i / div) % vals; // lookup type 1
                else
                    off = i * cb->ndimentions + j; // lookup type 2

                cb->dimentions[i * cb->ndimentions + j] = last + cb->min + cb->quantlist[off] * cb->delta;
                if (cb->seq_p)
                    last = cb->dimentions[i * cb->ndimentions + j];
                cb->pow2[i] += cb->dimentions[i * cb->ndimentions + j] * cb->dimentions[i * cb->ndimentions + j];
                div *= vals;
            }
            cb->pow2[i] /= 2.;
        }
    }
}

static void ready_residue(vorbis_enc_residue *rc, vorbis_enc_context *venc)
{
    int i;
    assert(rc->type == 2);
    rc->maxes = av_mallocz(sizeof(float[2]) * rc->classifications);
    for (i = 0; i < rc->classifications; i++) {
        int j;
        vorbis_enc_codebook * cb;
        for (j = 0; j < 8; j++)
            if (rc->books[i][j] != -1)
                break;
        if (j == 8) // zero
            continue;
        cb = &venc->codebooks[rc->books[i][j]];
        assert(cb->ndimentions >= 2);
        assert(cb->lookup);

        for (j = 0; j < cb->nentries; j++) {
            float a;
            if (!cb->lens[j])
                continue;
            a = fabs(cb->dimentions[j * cb->ndimentions]);
            if (a > rc->maxes[i][0])
                rc->maxes[i][0] = a;
            a = fabs(cb->dimentions[j * cb->ndimentions + 1]);
            if (a > rc->maxes[i][1])
                rc->maxes[i][1] = a;
        }
    }
    // small bias
    for (i = 0; i < rc->classifications; i++) {
        rc->maxes[i][0] += 0.8;
        rc->maxes[i][1] += 0.8;
    }
}

static void create_vorbis_context(vorbis_enc_context *venc,
                                  AVCodecContext *avccontext)
{
    vorbis_enc_floor   *fc;
    vorbis_enc_residue *rc;
    vorbis_enc_mapping *mc;
    int i, book;

    venc->channels    = avccontext->channels;
    venc->sample_rate = avccontext->sample_rate;
    venc->log2_blocksize[0] = venc->log2_blocksize[1] = 11;

    venc->ncodebooks = FF_ARRAY_ELEMS(cvectors);
    venc->codebooks  = av_malloc(sizeof(vorbis_enc_codebook) * venc->ncodebooks);

    // codebook 0..14 - floor1 book, values 0..255
    // codebook 15 residue masterbook
    // codebook 16..29 residue
    for (book = 0; book < venc->ncodebooks; book++) {
        vorbis_enc_codebook *cb = &venc->codebooks[book];
        int vals;
        cb->ndimentions = cvectors[book].dim;
        cb->nentries    = cvectors[book].real_len;
        cb->min         = cvectors[book].min;
        cb->delta       = cvectors[book].delta;
        cb->lookup      = cvectors[book].lookup;
        cb->seq_p       = 0;

        cb->lens      = av_malloc(sizeof(uint8_t)  * cb->nentries);
        cb->codewords = av_malloc(sizeof(uint32_t) * cb->nentries);
        memcpy(cb->lens, cvectors[book].clens, cvectors[book].len);
        memset(cb->lens + cvectors[book].len, 0, cb->nentries - cvectors[book].len);

        if (cb->lookup) {
            vals = cb_lookup_vals(cb->lookup, cb->ndimentions, cb->nentries);
            cb->quantlist = av_malloc(sizeof(int) * vals);
            for (i = 0; i < vals; i++)
                cb->quantlist[i] = cvectors[book].quant[i];
        } else {
            cb->quantlist = NULL;
        }
        ready_codebook(cb);
    }

    venc->nfloors = 1;
    venc->floors  = av_malloc(sizeof(vorbis_enc_floor) * venc->nfloors);

    // just 1 floor
    fc = &venc->floors[0];
    fc->partitions         = 8;
    fc->partition_to_class = av_malloc(sizeof(int) * fc->partitions);
    fc->nclasses           = 0;
    for (i = 0; i < fc->partitions; i++) {
        static const int a[] = {0, 1, 2, 2, 3, 3, 4, 4};
        fc->partition_to_class[i] = a[i];
        fc->nclasses = FFMAX(fc->nclasses, fc->partition_to_class[i]);
    }
    fc->nclasses++;
    fc->classes = av_malloc(sizeof(vorbis_enc_floor_class) * fc->nclasses);
    for (i = 0; i < fc->nclasses; i++) {
        vorbis_enc_floor_class * c = &fc->classes[i];
        int j, books;
        c->dim        = floor_classes[i].dim;
        c->subclass   = floor_classes[i].subclass;
        c->masterbook = floor_classes[i].masterbook;
        books         = (1 << c->subclass);
        c->books      = av_malloc(sizeof(int) * books);
        for (j = 0; j < books; j++)
            c->books[j] = floor_classes[i].nbooks[j];
    }
    fc->multiplier = 2;
    fc->rangebits  = venc->log2_blocksize[0] - 1;

    fc->values = 2;
    for (i = 0; i < fc->partitions; i++)
        fc->values += fc->classes[fc->partition_to_class[i]].dim;

    fc->list = av_malloc(sizeof(vorbis_floor1_entry) * fc->values);
    fc->list[0].x = 0;
    fc->list[1].x = 1 << fc->rangebits;
    for (i = 2; i < fc->values; i++) {
        static const int a[] = {
             93, 23,372,  6, 46,186,750, 14, 33, 65,
            130,260,556,  3, 10, 18, 28, 39, 55, 79,
            111,158,220,312,464,650,850
        };
        fc->list[i].x = a[i - 2];
    }
    ff_vorbis_ready_floor1_list(fc->list, fc->values);

    venc->nresidues = 1;
    venc->residues  = av_malloc(sizeof(vorbis_enc_residue) * venc->nresidues);

    // single residue
    rc = &venc->residues[0];
    rc->type            = 2;
    rc->begin           = 0;
    rc->end             = 1600;
    rc->partition_size  = 32;
    rc->classifications = 10;
    rc->classbook       = 15;
    rc->books           = av_malloc(sizeof(*rc->books) * rc->classifications);
    {
        static const int8_t a[10][8] = {
            { -1, -1, -1, -1, -1, -1, -1, -1, },
            { -1, -1, 16, -1, -1, -1, -1, -1, },
            { -1, -1, 17, -1, -1, -1, -1, -1, },
            { -1, -1, 18, -1, -1, -1, -1, -1, },
            { -1, -1, 19, -1, -1, -1, -1, -1, },
            { -1, -1, 20, -1, -1, -1, -1, -1, },
            { -1, -1, 21, -1, -1, -1, -1, -1, },
            { 22, 23, -1, -1, -1, -1, -1, -1, },
            { 24, 25, -1, -1, -1, -1, -1, -1, },
            { 26, 27, 28, -1, -1, -1, -1, -1, },
        };
        memcpy(rc->books, a, sizeof a);
    }
    ready_residue(rc, venc);

    venc->nmappings = 1;
    venc->mappings  = av_malloc(sizeof(vorbis_enc_mapping) * venc->nmappings);

    // single mapping
    mc = &venc->mappings[0];
    mc->submaps = 1;
    mc->mux     = av_malloc(sizeof(int) * venc->channels);
    for (i = 0; i < venc->channels; i++)
        mc->mux[i] = 0;
    mc->floor   = av_malloc(sizeof(int) * mc->submaps);
    mc->residue = av_malloc(sizeof(int) * mc->submaps);
    for (i = 0; i < mc->submaps; i++) {
        mc->floor[i]   = 0;
        mc->residue[i] = 0;
    }
    mc->coupling_steps = venc->channels == 2 ? 1 : 0;
    mc->magnitude      = av_malloc(sizeof(int) * mc->coupling_steps);
    mc->angle          = av_malloc(sizeof(int) * mc->coupling_steps);
    if (mc->coupling_steps) {
        mc->magnitude[0] = 0;
        mc->angle[0]     = 1;
    }

    venc->nmodes = 1;
    venc->modes  = av_malloc(sizeof(vorbis_enc_mode) * venc->nmodes);

    // single mode
    venc->modes[0].blockflag = 0;
    venc->modes[0].mapping   = 0;

    venc->have_saved = 0;
    venc->saved      = av_malloc(sizeof(float) * venc->channels * (1 << venc->log2_blocksize[1]) / 2);
    venc->samples    = av_malloc(sizeof(float) * venc->channels * (1 << venc->log2_blocksize[1]));
    venc->floor      = av_malloc(sizeof(float) * venc->channels * (1 << venc->log2_blocksize[1]) / 2);
    venc->coeffs     = av_malloc(sizeof(float) * venc->channels * (1 << venc->log2_blocksize[1]) / 2);

    venc->win[0] = ff_vorbis_vwin[venc->log2_blocksize[0] - 6];
    venc->win[1] = ff_vorbis_vwin[venc->log2_blocksize[1] - 6];

    ff_mdct_init(&venc->mdct[0], venc->log2_blocksize[0], 0, 1.0);
    ff_mdct_init(&venc->mdct[1], venc->log2_blocksize[1], 0, 1.0);
}

static void put_float(PutBitContext *pb, float f)
{
    int exp, mant;
    uint32_t res = 0;
    mant = (int)ldexp(frexp(f, &exp), 20);
    exp += 788 - 20;
    if (mant < 0) {
        res |= (1 << 31);
        mant = -mant;
    }
    res |= mant | (exp << 21);
    put_bits32(pb, res);
}

static void put_codebook_header(PutBitContext *pb, vorbis_enc_codebook *cb)
{
    int i;
    int ordered = 0;

    put_bits(pb, 24, 0x564342); //magic
    put_bits(pb, 16, cb->ndimentions);
    put_bits(pb, 24, cb->nentries);

    for (i = 1; i < cb->nentries; i++)
        if (cb->lens[i] < cb->lens[i-1])
            break;
    if (i == cb->nentries)
        ordered = 1;

    put_bits(pb, 1, ordered);
    if (ordered) {
        int len = cb->lens[0];
        put_bits(pb, 5, len - 1);
        i = 0;
        while (i < cb->nentries) {
            int j;
            for (j = 0; j+i < cb->nentries; j++)
                if (cb->lens[j+i] != len)
                    break;
            put_bits(pb, ilog(cb->nentries - i), j);
            i += j;
            len++;
        }
    } else {
        int sparse = 0;
        for (i = 0; i < cb->nentries; i++)
            if (!cb->lens[i])
                break;
        if (i != cb->nentries)
            sparse = 1;
        put_bits(pb, 1, sparse);

        for (i = 0; i < cb->nentries; i++) {
            if (sparse)
                put_bits(pb, 1, !!cb->lens[i]);
            if (cb->lens[i])
                put_bits(pb, 5, cb->lens[i] - 1);
        }
    }

    put_bits(pb, 4, cb->lookup);
    if (cb->lookup) {
        int tmp  = cb_lookup_vals(cb->lookup, cb->ndimentions, cb->nentries);
        int bits = ilog(cb->quantlist[0]);

        for (i = 1; i < tmp; i++)
            bits = FFMAX(bits, ilog(cb->quantlist[i]));

        put_float(pb, cb->min);
        put_float(pb, cb->delta);

        put_bits(pb, 4, bits - 1);
        put_bits(pb, 1, cb->seq_p);

        for (i = 0; i < tmp; i++)
            put_bits(pb, bits, cb->quantlist[i]);
    }
}

static void put_floor_header(PutBitContext *pb, vorbis_enc_floor *fc)
{
    int i;

    put_bits(pb, 16, 1); // type, only floor1 is supported

    put_bits(pb, 5, fc->partitions);

    for (i = 0; i < fc->partitions; i++)
        put_bits(pb, 4, fc->partition_to_class[i]);

    for (i = 0; i < fc->nclasses; i++) {
        int j, books;

        put_bits(pb, 3, fc->classes[i].dim - 1);
        put_bits(pb, 2, fc->classes[i].subclass);

        if (fc->classes[i].subclass)
            put_bits(pb, 8, fc->classes[i].masterbook);

        books = (1 << fc->classes[i].subclass);

        for (j = 0; j < books; j++)
            put_bits(pb, 8, fc->classes[i].books[j] + 1);
    }

    put_bits(pb, 2, fc->multiplier - 1);
    put_bits(pb, 4, fc->rangebits);

    for (i = 2; i < fc->values; i++)
        put_bits(pb, fc->rangebits, fc->list[i].x);
}

static void put_residue_header(PutBitContext *pb, vorbis_enc_residue *rc)
{
    int i;

    put_bits(pb, 16, rc->type);

    put_bits(pb, 24, rc->begin);
    put_bits(pb, 24, rc->end);
    put_bits(pb, 24, rc->partition_size - 1);
    put_bits(pb, 6, rc->classifications - 1);
    put_bits(pb, 8, rc->classbook);

    for (i = 0; i < rc->classifications; i++) {
        int j, tmp = 0;
        for (j = 0; j < 8; j++)
            tmp |= (rc->books[i][j] != -1) << j;

        put_bits(pb, 3, tmp & 7);
        put_bits(pb, 1, tmp > 7);

        if (tmp > 7)
            put_bits(pb, 5, tmp >> 3);
    }

    for (i = 0; i < rc->classifications; i++) {
        int j;
        for (j = 0; j < 8; j++)
            if (rc->books[i][j] != -1)
                put_bits(pb, 8, rc->books[i][j]);
    }
}

static int put_main_header(vorbis_enc_context *venc, uint8_t **out)
{
    int i;
    PutBitContext pb;
    uint8_t buffer[50000] = {0}, *p = buffer;
    int buffer_len = sizeof buffer;
    int len, hlens[3];

    // identification header
    init_put_bits(&pb, p, buffer_len);
    put_bits(&pb, 8, 1); //magic
    for (i = 0; "vorbis"[i]; i++)
        put_bits(&pb, 8, "vorbis"[i]);
    put_bits32(&pb, 0); // version
    put_bits(&pb,  8, venc->channels);
    put_bits32(&pb, venc->sample_rate);
    put_bits32(&pb, 0); // bitrate
    put_bits32(&pb, 0); // bitrate
    put_bits32(&pb, 0); // bitrate
    put_bits(&pb,  4, venc->log2_blocksize[0]);
    put_bits(&pb,  4, venc->log2_blocksize[1]);
    put_bits(&pb,  1, 1); // framing

    flush_put_bits(&pb);
    hlens[0] = put_bits_count(&pb) >> 3;
    buffer_len -= hlens[0];
    p += hlens[0];

    // comment header
    init_put_bits(&pb, p, buffer_len);
    put_bits(&pb, 8, 3); //magic
    for (i = 0; "vorbis"[i]; i++)
        put_bits(&pb, 8, "vorbis"[i]);
    put_bits32(&pb, 0); // vendor length TODO
    put_bits32(&pb, 0); // amount of comments
    put_bits(&pb,  1, 1); // framing

    flush_put_bits(&pb);
    hlens[1] = put_bits_count(&pb) >> 3;
    buffer_len -= hlens[1];
    p += hlens[1];

    // setup header
    init_put_bits(&pb, p, buffer_len);
    put_bits(&pb, 8, 5); //magic
    for (i = 0; "vorbis"[i]; i++)
        put_bits(&pb, 8, "vorbis"[i]);

    // codebooks
    put_bits(&pb, 8, venc->ncodebooks - 1);
    for (i = 0; i < venc->ncodebooks; i++)
        put_codebook_header(&pb, &venc->codebooks[i]);

    // time domain, reserved, zero
    put_bits(&pb,  6, 0);
    put_bits(&pb, 16, 0);

    // floors
    put_bits(&pb, 6, venc->nfloors - 1);
    for (i = 0; i < venc->nfloors; i++)
        put_floor_header(&pb, &venc->floors[i]);

    // residues
    put_bits(&pb, 6, venc->nresidues - 1);
    for (i = 0; i < venc->nresidues; i++)
        put_residue_header(&pb, &venc->residues[i]);

    // mappings
    put_bits(&pb, 6, venc->nmappings - 1);
    for (i = 0; i < venc->nmappings; i++) {
        vorbis_enc_mapping *mc = &venc->mappings[i];
        int j;
        put_bits(&pb, 16, 0); // mapping type

        put_bits(&pb, 1, mc->submaps > 1);
        if (mc->submaps > 1)
            put_bits(&pb, 4, mc->submaps - 1);

        put_bits(&pb, 1, !!mc->coupling_steps);
        if (mc->coupling_steps) {
            put_bits(&pb, 8, mc->coupling_steps - 1);
            for (j = 0; j < mc->coupling_steps; j++) {
                put_bits(&pb, ilog(venc->channels - 1), mc->magnitude[j]);
                put_bits(&pb, ilog(venc->channels - 1), mc->angle[j]);
            }
        }

        put_bits(&pb, 2, 0); // reserved

        if (mc->submaps > 1)
            for (j = 0; j < venc->channels; j++)
                put_bits(&pb, 4, mc->mux[j]);

        for (j = 0; j < mc->submaps; j++) {
            put_bits(&pb, 8, 0); // reserved time configuration
            put_bits(&pb, 8, mc->floor[j]);
            put_bits(&pb, 8, mc->residue[j]);
        }
    }

    // modes
    put_bits(&pb, 6, venc->nmodes - 1);
    for (i = 0; i < venc->nmodes; i++) {
        put_bits(&pb, 1, venc->modes[i].blockflag);
        put_bits(&pb, 16, 0); // reserved window type
        put_bits(&pb, 16, 0); // reserved transform type
        put_bits(&pb, 8, venc->modes[i].mapping);
    }

    put_bits(&pb, 1, 1); // framing

    flush_put_bits(&pb);
    hlens[2] = put_bits_count(&pb) >> 3;

    len = hlens[0] + hlens[1] + hlens[2];
    p = *out = av_mallocz(64 + len + len/255);

    *p++ = 2;
    p += av_xiphlacing(p, hlens[0]);
    p += av_xiphlacing(p, hlens[1]);
    buffer_len = 0;
    for (i = 0; i < 3; i++) {
        memcpy(p, buffer + buffer_len, hlens[i]);
        p += hlens[i];
        buffer_len += hlens[i];
    }

    return p - *out;
}

static float get_floor_average(vorbis_enc_floor * fc, float *coeffs, int i)
{
    int begin = fc->list[fc->list[FFMAX(i-1, 0)].sort].x;
    int end   = fc->list[fc->list[FFMIN(i+1, fc->values - 1)].sort].x;
    int j;
    float average = 0;

    for (j = begin; j < end; j++)
        average += fabs(coeffs[j]);
    return average / (end - begin);
}

static void floor_fit(vorbis_enc_context *venc, vorbis_enc_floor *fc,
                      float *coeffs, uint_fast16_t *posts, int samples)
{
    int range = 255 / fc->multiplier + 1;
    int i;
    float tot_average = 0.;
    float averages[fc->values];
    for (i = 0; i < fc->values; i++) {
        averages[i] = get_floor_average(fc, coeffs, i);
        tot_average += averages[i];
    }
    tot_average /= fc->values;
    tot_average /= venc->quality;

    for (i = 0; i < fc->values; i++) {
        int position  = fc->list[fc->list[i].sort].x;
        float average = averages[i];
        int j;

        average *= pow(tot_average / average, 0.5) * pow(1.25, position/200.); // MAGIC!
        for (j = 0; j < range - 1; j++)
            if (ff_vorbis_floor1_inverse_db_table[j * fc->multiplier] > average)
                break;
        posts[fc->list[i].sort] = j;
    }
}

static int render_point(int x0, int y0, int x1, int y1, int x)
{
    return y0 +  (x - x0) * (y1 - y0) / (x1 - x0);
}

static void floor_encode(vorbis_enc_context *venc, vorbis_enc_floor *fc,
                         PutBitContext *pb, uint_fast16_t *posts,
                         float *floor, int samples)
{
    int range = 255 / fc->multiplier + 1;
    int coded[fc->values]; // first 2 values are unused
    int i, counter;

    put_bits(pb, 1, 1); // non zero
    put_bits(pb, ilog(range - 1), posts[0]);
    put_bits(pb, ilog(range - 1), posts[1]);
    coded[0] = coded[1] = 1;

    for (i = 2; i < fc->values; i++) {
        int predicted = render_point(fc->list[fc->list[i].low].x,
                                     posts[fc->list[i].low],
                                     fc->list[fc->list[i].high].x,
                                     posts[fc->list[i].high],
                                     fc->list[i].x);
        int highroom = range - predicted;
        int lowroom = predicted;
        int room = FFMIN(highroom, lowroom);
        if (predicted == posts[i]) {
            coded[i] = 0; // must be used later as flag!
            continue;
        } else {
            if (!coded[fc->list[i].low ])
                coded[fc->list[i].low ] = -1;
            if (!coded[fc->list[i].high])
                coded[fc->list[i].high] = -1;
        }
        if (posts[i] > predicted) {
            if (posts[i] - predicted > room)
                coded[i] = posts[i] - predicted + lowroom;
            else
                coded[i] = (posts[i] - predicted) << 1;
        } else {
            if (predicted - posts[i] > room)
                coded[i] = predicted - posts[i] + highroom - 1;
            else
                coded[i] = ((predicted - posts[i]) << 1) - 1;
        }
    }

    counter = 2;
    for (i = 0; i < fc->partitions; i++) {
        vorbis_enc_floor_class * c = &fc->classes[fc->partition_to_class[i]];
        int k, cval = 0, csub = 1<<c->subclass;
        if (c->subclass) {
            vorbis_enc_codebook * book = &venc->codebooks[c->masterbook];
            int cshift = 0;
            for (k = 0; k < c->dim; k++) {
                int l;
                for (l = 0; l < csub; l++) {
                    int maxval = 1;
                    if (c->books[l] != -1)
                        maxval = venc->codebooks[c->books[l]].nentries;
                    // coded could be -1, but this still works, cause that is 0
                    if (coded[counter + k] < maxval)
                        break;
                }
                assert(l != csub);
                cval   |= l << cshift;
                cshift += c->subclass;
            }
            put_codeword(pb, book, cval);
        }
        for (k = 0; k < c->dim; k++) {
            int book  = c->books[cval & (csub-1)];
            int entry = coded[counter++];
            cval >>= c->subclass;
            if (book == -1)
                continue;
            if (entry == -1)
                entry = 0;
            put_codeword(pb, &venc->codebooks[book], entry);
        }
    }

    ff_vorbis_floor1_render_list(fc->list, fc->values, posts, coded,
                                 fc->multiplier, floor, samples);
}

static float *put_vector(vorbis_enc_codebook *book, PutBitContext *pb,
                         float *num)
{
    int i, entry = -1;
    float distance = FLT_MAX;
    assert(book->dimentions);
    for (i = 0; i < book->nentries; i++) {
        float * vec = book->dimentions + i * book->ndimentions, d = book->pow2[i];
        int j;
        if (!book->lens[i])
            continue;
        for (j = 0; j < book->ndimentions; j++)
            d -= vec[j] * num[j];
        if (distance > d) {
            entry    = i;
            distance = d;
        }
    }
    put_codeword(pb, book, entry);
    return &book->dimentions[entry * book->ndimentions];
}

static void residue_encode(vorbis_enc_context *venc, vorbis_enc_residue *rc,
                           PutBitContext *pb, float *coeffs, int samples,
                           int real_ch)
{
    int pass, i, j, p, k;
    int psize      = rc->partition_size;
    int partitions = (rc->end - rc->begin) / psize;
    int channels   = (rc->type == 2) ? 1 : real_ch;
    int classes[channels][partitions];
    int classwords = venc->codebooks[rc->classbook].ndimentions;

    assert(rc->type == 2);
    assert(real_ch == 2);
    for (p = 0; p < partitions; p++) {
        float max1 = 0., max2 = 0.;
        int s = rc->begin + p * psize;
        for (k = s; k < s + psize; k += 2) {
            max1 = FFMAX(max1, fabs(coeffs[          k / real_ch]));
            max2 = FFMAX(max2, fabs(coeffs[samples + k / real_ch]));
        }

        for (i = 0; i < rc->classifications - 1; i++)
            if (max1 < rc->maxes[i][0] && max2 < rc->maxes[i][1])
                break;
        classes[0][p] = i;
    }

    for (pass = 0; pass < 8; pass++) {
        p = 0;
        while (p < partitions) {
            if (pass == 0)
                for (j = 0; j < channels; j++) {
                    vorbis_enc_codebook * book = &venc->codebooks[rc->classbook];
                    int entry = 0;
                    for (i = 0; i < classwords; i++) {
                        entry *= rc->classifications;
                        entry += classes[j][p + i];
                    }
                    put_codeword(pb, book, entry);
                }
            for (i = 0; i < classwords && p < partitions; i++, p++) {
                for (j = 0; j < channels; j++) {
                    int nbook = rc->books[classes[j][p]][pass];
                    vorbis_enc_codebook * book = &venc->codebooks[nbook];
                    float *buf = coeffs + samples*j + rc->begin + p*psize;
                    if (nbook == -1)
                        continue;

                    assert(rc->type == 0 || rc->type == 2);
                    assert(!(psize % book->ndimentions));

                    if (rc->type == 0) {
                        for (k = 0; k < psize; k += book->ndimentions) {
                            float *a = put_vector(book, pb, &buf[k]);
                            int l;
                            for (l = 0; l < book->ndimentions; l++)
                                buf[k + l] -= a[l];
                        }
                    } else {
                        int s = rc->begin + p * psize, a1, b1;
                        a1 = (s % real_ch) * samples;
                        b1 =  s / real_ch;
                        s  = real_ch * samples;
                        for (k = 0; k < psize; k += book->ndimentions) {
                            int dim, a2 = a1, b2 = b1;
                            float vec[book->ndimentions], *pv = vec;
                            for (dim = book->ndimentions; dim--; ) {
                                *pv++ = coeffs[a2 + b2];
                                if ((a2 += samples) == s) {
                                    a2 = 0;
                                    b2++;
                                }
                            }
                            pv = put_vector(book, pb, vec);
                            for (dim = book->ndimentions; dim--; ) {
                                coeffs[a1 + b1] -= *pv++;
                                if ((a1 += samples) == s) {
                                    a1 = 0;
                                    b1++;
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

static int apply_window_and_mdct(vorbis_enc_context *venc, signed short *audio,
                                 int samples)
{
    int i, j, channel;
    const float * win = venc->win[0];
    int window_len = 1 << (venc->log2_blocksize[0] - 1);
    float n = (float)(1 << venc->log2_blocksize[0]) / 4.;
    // FIXME use dsp

    if (!venc->have_saved && !samples)
        return 0;

    if (venc->have_saved) {
        for (channel = 0; channel < venc->channels; channel++)
            memcpy(venc->samples + channel * window_len * 2,
                   venc->saved + channel * window_len, sizeof(float) * window_len);
    } else {
        for (channel = 0; channel < venc->channels; channel++)
            memset(venc->samples + channel * window_len * 2, 0,
                   sizeof(float) * window_len);
    }

    if (samples) {
        for (channel = 0; channel < venc->channels; channel++) {
            float * offset = venc->samples + channel*window_len*2 + window_len;
            j = channel;
            for (i = 0; i < samples; i++, j += venc->channels)
                offset[i] = -audio[j] / 32768. / n * win[window_len - i - 1]; //FIXME find out why the sign has to be fliped
        }
    } else {
        for (channel = 0; channel < venc->channels; channel++)
            memset(venc->samples + channel * window_len * 2 + window_len,
                   0, sizeof(float) * window_len);
    }

    for (channel = 0; channel < venc->channels; channel++)
        ff_mdct_calc(&venc->mdct[0], venc->coeffs + channel * window_len,
                     venc->samples + channel * window_len * 2);

    if (samples) {
        for (channel = 0; channel < venc->channels; channel++) {
            float *offset = venc->saved + channel * window_len;
            j = channel;
            for (i = 0; i < samples; i++, j += venc->channels)
                offset[i] = -audio[j] / 32768. / n * win[i]; //FIXME find out why the sign has to be fliped
        }
        venc->have_saved = 1;
    } else {
        venc->have_saved = 0;
    }
    return 1;
}

static av_cold int vorbis_encode_init(AVCodecContext *avccontext)
{
    vorbis_enc_context *venc = avccontext->priv_data;

    if (avccontext->channels != 2) {
        av_log(avccontext, AV_LOG_ERROR, "Current FFmpeg Vorbis encoder only supports 2 channels.\n");
        return -1;
    }

    create_vorbis_context(venc, avccontext);

    if (avccontext->flags & CODEC_FLAG_QSCALE)
        venc->quality = avccontext->global_quality / (float)FF_QP2LAMBDA / 10.;
    else
        venc->quality = 1.;
    venc->quality *= venc->quality;

    avccontext->extradata_size = put_main_header(venc, (uint8_t**)&avccontext->extradata);

    avccontext->frame_size     = 1 << (venc->log2_blocksize[0] - 1);

    avccontext->coded_frame            = avcodec_alloc_frame();
    avccontext->coded_frame->key_frame = 1;

    return 0;
}

static int vorbis_encode_frame(AVCodecContext *avccontext,
                               unsigned char *packets,
                               int buf_size, void *data)
{
    vorbis_enc_context *venc = avccontext->priv_data;
    signed short *audio = data;
    int samples = data ? avccontext->frame_size : 0;
    vorbis_enc_mode *mode;
    vorbis_enc_mapping *mapping;
    PutBitContext pb;
    int i;

    if (!apply_window_and_mdct(venc, audio, samples))
        return 0;
    samples = 1 << (venc->log2_blocksize[0] - 1);

    init_put_bits(&pb, packets, buf_size);

    put_bits(&pb, 1, 0); // magic bit

    put_bits(&pb, ilog(venc->nmodes - 1), 0); // 0 bits, the mode

    mode    = &venc->modes[0];
    mapping = &venc->mappings[mode->mapping];
    if (mode->blockflag) {
        put_bits(&pb, 1, 0);
        put_bits(&pb, 1, 0);
    }

    for (i = 0; i < venc->channels; i++) {
        vorbis_enc_floor *fc = &venc->floors[mapping->floor[mapping->mux[i]]];
        uint_fast16_t posts[fc->values];
        floor_fit(venc, fc, &venc->coeffs[i * samples], posts, samples);
        floor_encode(venc, fc, &pb, posts, &venc->floor[i * samples], samples);
    }

    for (i = 0; i < venc->channels * samples; i++)
        venc->coeffs[i] /= venc->floor[i];

    for (i = 0; i < mapping->coupling_steps; i++) {
        float *mag = venc->coeffs + mapping->magnitude[i] * samples;
        float *ang = venc->coeffs + mapping->angle[i]     * samples;
        int j;
        for (j = 0; j < samples; j++) {
            float a = ang[j];
            ang[j] -= mag[j];
            if (mag[j] > 0)
                ang[j] = -ang[j];
            if (ang[j] < 0)
                mag[j] = a;
        }
    }

    residue_encode(venc, &venc->residues[mapping->residue[mapping->mux[0]]],
                   &pb, venc->coeffs, samples, venc->channels);

    avccontext->coded_frame->pts = venc->sample_count;
    venc->sample_count += avccontext->frame_size;
    flush_put_bits(&pb);
    return put_bits_count(&pb) >> 3;
}


static av_cold int vorbis_encode_close(AVCodecContext *avccontext)
{
    vorbis_enc_context *venc = avccontext->priv_data;
    int i;

    if (venc->codebooks)
        for (i = 0; i < venc->ncodebooks; i++) {
            av_freep(&venc->codebooks[i].lens);
            av_freep(&venc->codebooks[i].codewords);
            av_freep(&venc->codebooks[i].quantlist);
            av_freep(&venc->codebooks[i].dimentions);
            av_freep(&venc->codebooks[i].pow2);
        }
    av_freep(&venc->codebooks);

    if (venc->floors)
        for (i = 0; i < venc->nfloors; i++) {
            int j;
            if (venc->floors[i].classes)
                for (j = 0; j < venc->floors[i].nclasses; j++)
                    av_freep(&venc->floors[i].classes[j].books);
            av_freep(&venc->floors[i].classes);
            av_freep(&venc->floors[i].partition_to_class);
            av_freep(&venc->floors[i].list);
        }
    av_freep(&venc->floors);

    if (venc->residues)
        for (i = 0; i < venc->nresidues; i++) {
            av_freep(&venc->residues[i].books);
            av_freep(&venc->residues[i].maxes);
        }
    av_freep(&venc->residues);

    if (venc->mappings)
        for (i = 0; i < venc->nmappings; i++) {
            av_freep(&venc->mappings[i].mux);
            av_freep(&venc->mappings[i].floor);
            av_freep(&venc->mappings[i].residue);
            av_freep(&venc->mappings[i].magnitude);
            av_freep(&venc->mappings[i].angle);
        }
    av_freep(&venc->mappings);

    av_freep(&venc->modes);

    av_freep(&venc->saved);
    av_freep(&venc->samples);
    av_freep(&venc->floor);
    av_freep(&venc->coeffs);

    ff_mdct_end(&venc->mdct[0]);
    ff_mdct_end(&venc->mdct[1]);

    av_freep(&avccontext->coded_frame);
    av_freep(&avccontext->extradata);

    return 0 ;
}

AVCodec vorbis_encoder = {
    "vorbis",
    CODEC_TYPE_AUDIO,
    CODEC_ID_VORBIS,
    sizeof(vorbis_enc_context),
    vorbis_encode_init,
    vorbis_encode_frame,
    vorbis_encode_close,
    .capabilities= CODEC_CAP_DELAY,
    .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
    .long_name = NULL_IF_CONFIG_SMALL("Vorbis"),
};