format_ogg_vorbis.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2005, Jeff Ollie
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief OGG/Vorbis streams.
 * \arg File name extension: ogg
 * \ingroup formats
 */
 
/* the order of these dependencies is important... it also specifies
   the link order of the libraries during linking
*/
 
/*** MODULEINFO
    <depend>vorbis</depend>
    <depend>ogg</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <ogg/ogg.h>
#include <vorbis/codec.h>
#include <vorbis/vorbisenc.h>
#include <vorbis/vorbisfile.h>
 
#ifdef _WIN32
#include <io.h>
#endif
 
#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/format_cache.h"
 
/*
 * this is the number of samples we deal with. Samples are converted
 * to SLINEAR so each one uses 2 bytes in the buffer.
 */
#define SAMPLES_MAX 512
#define BUF_SIZE    (2*SAMPLES_MAX)
 
#define BLOCK_SIZE 4096     /* used internally in the vorbis routines */
 
struct ogg_vorbis_desc {    /* format specific parameters */
    /* OggVorbis_File structure for libvorbisfile interface */
    OggVorbis_File ov_f;
 
    /* structures for handling the Ogg container */
    ogg_stream_state os;
    ogg_page og;
    ogg_packet op;
 
    /* structures for handling Vorbis audio data */
    vorbis_info vi;
    vorbis_comment vc;
    vorbis_dsp_state vd;
    vorbis_block vb;
 
    /*! \brief Indicates whether this filestream is set up for reading or writing. */
    int writing;
 
    /*! \brief Stores the current pcm position to support tell() on writing mode. */
    off_t writing_pcm_pos;
 
    /*! \brief Indicates whether an End of Stream condition has been detected. */
    int eos;
};
 
#if !defined(HAVE_VORBIS_OPEN_CALLBACKS)
/*
 * Declared for backward compatibility with vorbisfile v1.1.2.
 * Code taken from vorbisfile.h v1.2.0.
 */
static int _ov_header_fseek_wrap(FILE *f, ogg_int64_t off, int whence)
{
    if (f == NULL) {
        return -1;
    }
    return fseek(f, off, whence);
}
 
static ov_callbacks OV_CALLBACKS_NOCLOSE = {
  (size_t (*)(void *, size_t, size_t, void *))  fread,
  (int (*)(void *, ogg_int64_t, int))           _ov_header_fseek_wrap,
  (int (*)(void *))                             NULL,
  (long (*)(void *))                            ftell
};
#endif  /* !defined(HAVE_VORBIS_OPEN_CALLBACKS) */
 
/*!
 * \brief Create a new OGG/Vorbis filestream and set it up for reading.
 * \param s File that points to on disk storage of the OGG/Vorbis data.
 * \return The new filestream.
 */
static int ogg_vorbis_open(struct ast_filestream *s)
{
    int result;
    struct ogg_vorbis_desc *desc = (struct ogg_vorbis_desc *) s->_private;
 
    /* initialize private description block */
    memset(desc, 0, sizeof(struct ogg_vorbis_desc));
    desc->writing = 0;
 
    /* actually open file */
    result = ov_open_callbacks(s->f, &desc->ov_f, NULL, 0, OV_CALLBACKS_NOCLOSE);
    if (result != 0) {
        ast_log(LOG_ERROR, "Error opening Ogg/Vorbis file stream.\n");
        return -1;
    }
 
    /* check stream(s) type */
    if (desc->ov_f.vi->channels != 1) {
        ast_log(LOG_ERROR, "Only monophonic OGG/Vorbis files are currently supported!\n");
        ov_clear(&desc->ov_f);
        return -1;
    }
 
    if (desc->ov_f.vi->rate != DEFAULT_SAMPLE_RATE) {
        ast_log(LOG_ERROR, "Only 8000Hz OGG/Vorbis files are currently supported!\n");
        ov_clear(&desc->ov_f);
        return -1;
    }
 
    return 0;
}
 
/*!
 * \brief Create a new OGG/Vorbis filestream and set it up for writing.
 * \param s File pointer that points to on-disk storage.
 * \param comment Comment that should be embedded in the OGG/Vorbis file.
 * \return A new filestream.
 */
static int ogg_vorbis_rewrite(struct ast_filestream *s,
                         const char *comment)
{
    ogg_packet header;
    ogg_packet header_comm;
    ogg_packet header_code;
    struct ogg_vorbis_desc *tmp = (struct ogg_vorbis_desc *) s->_private;
 
    tmp->writing = 1;
    tmp->writing_pcm_pos = 0;
 
    vorbis_info_init(&tmp->vi);
 
    if (vorbis_encode_init_vbr(&tmp->vi, 1, DEFAULT_SAMPLE_RATE, 0.4)) {
        ast_log(LOG_ERROR, "Unable to initialize Vorbis encoder!\n");
        vorbis_info_clear(&tmp->vi);
        return -1;
    }
 
    vorbis_comment_init(&tmp->vc);
    vorbis_comment_add_tag(&tmp->vc, "ENCODER", "Asterisk PBX");
    if (comment)
        vorbis_comment_add_tag(&tmp->vc, "COMMENT", (char *) comment);
 
    vorbis_analysis_init(&tmp->vd, &tmp->vi);
    vorbis_block_init(&tmp->vd, &tmp->vb);
 
    ogg_stream_init(&tmp->os, ast_random());
 
    vorbis_analysis_headerout(&tmp->vd, &tmp->vc, &header, &header_comm,
                  &header_code);
    ogg_stream_packetin(&tmp->os, &header);
    ogg_stream_packetin(&tmp->os, &header_comm);
    ogg_stream_packetin(&tmp->os, &header_code);
 
    while (!tmp->eos) {
        if (ogg_stream_flush(&tmp->os, &tmp->og) == 0)
            break;
        if (fwrite(tmp->og.header, 1, tmp->og.header_len, s->f) != tmp->og.header_len) {
            ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
        }
        if (fwrite(tmp->og.body, 1, tmp->og.body_len, s->f) != tmp->og.body_len) {
            ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
        }
        if (ogg_page_eos(&tmp->og))
            tmp->eos = 1;
    }
 
    return 0;
}
 
/*!
 * \brief Write out any pending encoded data.
 * \param s An OGG/Vorbis filestream.
 * \param f The file to write to.
 */
static void write_stream(struct ogg_vorbis_desc *s, FILE *f)
{
    while (vorbis_analysis_blockout(&s->vd, &s->vb) == 1) {
        vorbis_analysis(&s->vb, NULL);
        vorbis_bitrate_addblock(&s->vb);
 
        while (vorbis_bitrate_flushpacket(&s->vd, &s->op)) {
            ogg_stream_packetin(&s->os, &s->op);
            while (!s->eos) {
                if (ogg_stream_pageout(&s->os, &s->og) == 0) {
                    break;
                }
                if (fwrite(s->og.header, 1, s->og.header_len, f) != s->og.header_len) {
                    ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
                }
                if (fwrite(s->og.body, 1, s->og.body_len, f) != s->og.body_len) {
                    ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
                }
                if (ogg_page_eos(&s->og)) {
                    s->eos = 1;
                }
            }
        }
    }
}
 
/*!
 * \brief Write audio data from a frame to an OGG/Vorbis filestream.
 * \param fs An OGG/Vorbis filestream.
 * \param f A frame containing audio to be written to the filestream.
 * \return -1 if there was an error, 0 on success.
 */
static int ogg_vorbis_write(struct ast_filestream *fs, struct ast_frame *f)
{
    int i;
    float **buffer;
    short *data;
    struct ogg_vorbis_desc *s = (struct ogg_vorbis_desc *) fs->_private;
 
    if (!s->writing) {
        ast_log(LOG_ERROR, "This stream is not set up for writing!\n");
        return -1;
    }
    if (!f->datalen)
        return -1;
 
    data = (short *) f->data.ptr;
 
    buffer = vorbis_analysis_buffer(&s->vd, f->samples);
 
    for (i = 0; i < f->samples; i++)
        buffer[0][i] = (double)data[i] / 32768.0;
 
    vorbis_analysis_wrote(&s->vd, f->samples);
 
    write_stream(s, fs->f);
 
    s->writing_pcm_pos +=  f->samples;
 
    return 0;
}
 
/*!
 * \brief Close a OGG/Vorbis filestream.
 * \param fs A OGG/Vorbis filestream.
 */
static void ogg_vorbis_close(struct ast_filestream *fs)
{
    struct ogg_vorbis_desc *s = (struct ogg_vorbis_desc *) fs->_private;
 
    if (s->writing) {
        /* Tell the Vorbis encoder that the stream is finished
         * and write out the rest of the data */
        vorbis_analysis_wrote(&s->vd, 0);
        write_stream(s, fs->f);
 
        /* Cleanup */
        ogg_stream_clear(&s->os);
        vorbis_block_clear(&s->vb);
        vorbis_dsp_clear(&s->vd);
        vorbis_comment_clear(&s->vc);
        vorbis_info_clear(&s->vi);
    } else {
        /* clear OggVorbis_File handle */
        ov_clear(&s->ov_f);
    }
}
 
/*!
 * \brief Read a frame full of audio data from the filestream.
 * \param fs The filestream.
 * \param whennext Number of sample times to schedule the next call.
 * \return A pointer to a frame containing audio data or NULL ifthere is no more audio data.
 */
static struct ast_frame *ogg_vorbis_read(struct ast_filestream *fs,
                     int *whennext)
{
    struct ogg_vorbis_desc *desc = (struct ogg_vorbis_desc *) fs->_private;
    int current_bitstream = -10;
    char *out_buf;
    long bytes_read;
 
    if (desc->writing) {
        ast_log(LOG_WARNING, "Reading is not supported on OGG/Vorbis on write files.\n");
        return NULL;
    }
 
    /* initialize frame */
    AST_FRAME_SET_BUFFER(&fs->fr, fs->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
    out_buf = (char *) (fs->fr.data.ptr);   /* SLIN data buffer */
 
    /* read samples from OV interface */
    bytes_read = ov_read(
        &desc->ov_f,
        out_buf,                        /* Buffer to write data */
        BUF_SIZE,                       /* Size of buffer */
        (__BYTE_ORDER == __BIG_ENDIAN), /* Endianes (0 for little) */
        2,                              /* 1 = 8bit, 2 = 16bit */
        1,                              /* 0 = unsigned, 1 = signed */
        &current_bitstream              /* Returns the current bitstream section */
    );
 
    /* check returned data */
    if (bytes_read <= 0) {
        /* End of stream */
        return NULL;
    }
 
    /* Return decoded bytes */
    fs->fr.datalen = bytes_read;
    fs->fr.samples = bytes_read / 2;
    *whennext = fs->fr.samples;
    return &fs->fr;
}
 
/*!
 * \brief Truncate an OGG/Vorbis filestream.
 * \param fs The filestream to truncate.
 * \return 0 on success, -1 on failure.
 */
 
static int ogg_vorbis_trunc(struct ast_filestream *fs)
{
    ast_log(LOG_WARNING, "Truncation is not supported on OGG/Vorbis streams!\n");
    return -1;
}
 
/*!
 * \brief Tell the current position in OGG/Vorbis filestream measured in pcms.
 * \param fs The filestream to take action on.
 * \return 0 or greater with the position measured in samples, or -1 for false.
 */
static off_t ogg_vorbis_tell(struct ast_filestream *fs)
{
    off_t pos;
    struct ogg_vorbis_desc *desc = (struct ogg_vorbis_desc *) fs->_private;
 
    if (desc->writing) {
        return desc->writing_pcm_pos;
    }
 
    if ((pos = ov_pcm_tell(&desc->ov_f)) < 0) {
        return -1;
    }
    return pos;
}
 
/*!
 * \brief Seek to a specific position in an OGG/Vorbis filestream.
 * \param fs The filestream to take action on.
 * \param sample_offset New position for the filestream, measured in 8KHz samples.
 * \param whence Location to measure
 * \return 0 on success, -1 on failure.
 */
static int ogg_vorbis_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
{
    int seek_result = -1;
    off_t relative_pcm_pos;
    struct ogg_vorbis_desc *desc = (struct ogg_vorbis_desc *) fs->_private;
 
    if (desc->writing) {
        ast_log(LOG_WARNING, "Seeking is not supported on OGG/Vorbis streams in writing mode!\n");
        return -1;
    }
 
    /* ov_pcm_seek support seeking only from begining (SEEK_SET), the rest must be emulated */
    switch (whence) {
    case SEEK_SET:
        seek_result = ov_pcm_seek(&desc->ov_f, sample_offset);
        break;
    case SEEK_CUR:
        if ((relative_pcm_pos = ogg_vorbis_tell(fs)) < 0) {
            seek_result = -1;
            break;
        }
        seek_result = ov_pcm_seek(&desc->ov_f, relative_pcm_pos + sample_offset);
        break;
    case SEEK_END:
        if ((relative_pcm_pos = ov_pcm_total(&desc->ov_f, -1)) < 0) {
            seek_result = -1;
            break;
        }
        seek_result = ov_pcm_seek(&desc->ov_f, relative_pcm_pos - sample_offset);
        break;
    default:
        ast_log(LOG_WARNING, "Unknown *whence* to seek on OGG/Vorbis streams!\n");
        break;
    }
 
    /* normalize error value to -1,0 */
    return (seek_result == 0) ? 0 : -1;
}
 
static struct ast_format_def vorbis_f = {
    .name = "ogg_vorbis",
    .exts = "ogg",
    .open = ogg_vorbis_open,
    .rewrite = ogg_vorbis_rewrite,
    .write = ogg_vorbis_write,
    .seek = ogg_vorbis_seek,
    .trunc = ogg_vorbis_trunc,
    .tell = ogg_vorbis_tell,
    .read = ogg_vorbis_read,
    .close = ogg_vorbis_close,
    .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
    .desc_size = sizeof(struct ogg_vorbis_desc),
};
 
static int load_module(void)
{
    vorbis_f.format = ast_format_slin;
    if (ast_format_def_register(&vorbis_f))
        return AST_MODULE_LOAD_DECLINE;
    return AST_MODULE_LOAD_SUCCESS;
}
 
static int unload_module(void)
{
    return ast_format_def_unregister(vorbis_f.name);
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "OGG/Vorbis audio",
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
    .load_pri = AST_MODPRI_APP_DEPEND
);