vorbis_enc.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * copyright (c) 2006 Oded Shimon <[e-mail]>
 *
 * 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 vorbis_enc.c
 * Native Vorbis encoder.
 * @author Oded Shimon <[e-mail]>
 */

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

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

typedef struct {
    int partitions;
    int * partition_to_class;
    int nclasses;
    floor_class_t * classes;
    int multiplier;
    int rangebits;
    int values;
    floor1_entry_t * list;
} floor_t;

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

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

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

typedef struct {
    int channels;
    int sample_rate;
    int log2_blocksize[2];
    MDCTContext 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;
    codebook_t * codebooks;

    int nfloors;
    floor_t * floors;

    int nresidues;
    residue_t * residues;

    int nmappings;
    mapping_t * mappings;

    int nmodes;
    vorbis_mode_t * modes;
} venc_context_t;

typedef struct {
    int total;
    int total_pos;
    int pos;
    uint8_t * buf_ptr;
} PutBitContext;

static inline void init_put_bits(PutBitContext * pb, uint8_t * buf, int buffer_len) {
    pb->total = buffer_len * 8;
    pb->total_pos = 0;
    pb->pos = 0;
    pb->buf_ptr = buf;
}

static void put_bits(PutBitContext * pb, int bits, uint64_t val) {
    if ((pb->total_pos += bits) >= pb->total) return;
    if (!bits) return;
    if (pb->pos) {
        if (pb->pos > bits) {
            *pb->buf_ptr |= val << (8 - pb->pos);
            pb->pos -= bits;
            bits = 0;
        } else {
            *pb->buf_ptr++ |= (val << (8 - pb->pos)) & 0xFF;
            val >>= pb->pos;
            bits -= pb->pos;
            pb->pos = 0;
        }
    }
    for (; bits >= 8; bits -= 8) {
        *pb->buf_ptr++ = val & 0xFF;
        val >>= 8;
    }
    if (bits) {
        *pb->buf_ptr = val;
        pb->pos = 8 - bits;
    }
}

static inline void flush_put_bits(PutBitContext * pb) {
}

static inline int put_bits_count(PutBitContext * pb) {
    return pb->total_pos;
}

static inline void put_codeword(PutBitContext * pb, codebook_t * 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(codebook_t * 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(residue_t * rc, venc_context_t * 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;
        codebook_t * cb;
        for (j = 0; j < 8; j++)
            if (rc->books[i][j] != -1) break;
        if (j == 8) continue; // zero
        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(venc_context_t * venc, AVCodecContext * avccontext) {
    floor_t * fc;
    residue_t * rc;
    mapping_t * 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 = sizeof(cvectors)/sizeof(cvectors[0]);
    venc->codebooks = av_malloc(sizeof(codebook_t) * 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++) {
        codebook_t * 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(floor_t) * 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(floor_class_t) * fc->nclasses);
    for (i = 0; i < fc->nclasses; i++) {
        floor_class_t * 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(floor1_entry_t) * 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(residue_t) * 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);