Decoding audio data

To decode audio data using libfishsound:. More...

To decode audio data using libfishsound:.

This procedure is illustrated in src/examples/fishsound-decode.c. Note that this example additionally:

Hence this example code demonstrates all that is needed to decode Ogg FLAC, Speex or Ogg Vorbis files:

/*
   Copyright (C) 2003 Commonwealth Scientific and Industrial Research
   Organisation (CSIRO) Australia

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

   - Neither the name of CSIRO Australia nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ORGANISATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <oggz/oggz.h>
#include <fishsound/fishsound.h>
#include <sndfile.h>

static char * infilename, * outfilename;
static int begun = 0;
static FishSoundInfo fsinfo;
static SNDFILE * sndfile;

/* In general, an Ogg file may contain multiple audio tracks in parallel.
 * To keep this example simple, we only decode the first track that we find.
 * Tracks ("logical bitstreams" in the Ogg documentations) are identified by
 * a serialno.
 */
static long decode_serialno = -1;

static int
open_output (int samplerate, int channels)
{
  SF_INFO sfinfo;

  sfinfo.samplerate = samplerate;
  sfinfo.channels = channels;
  sfinfo.format = SF_FORMAT_WAV | SF_FORMAT_PCM_16;

  sndfile = sf_open (outfilename, SFM_WRITE, &sfinfo);

  return 0;
}

static int
decoded_float (FishSound * fsound, float ** pcm, long frames, void * user_data)
{
  if (!begun) {
    fish_sound_command (fsound, FISH_SOUND_GET_INFO, &fsinfo,
                        sizeof (FishSoundInfo));
    open_output (fsinfo.samplerate, fsinfo.channels);
    begun = 1;
  }

  sf_writef_float (sndfile, (float *)pcm, frames);

  return 0;
}

static int
read_packet (OGGZ * oggz, ogg_packet * op, long serialno, void * user_data)
{
  FishSound * fsound = (FishSound *)user_data;

  /* If we have not yet selected an audio track to decode, then try
   * to identify this one. If it is a known audio codec, then remember its
   * serialno.
   * NB. We only try this if we are processing a BOS (beginning of stream)
   * packet, and it contains at least 8 bytes of data. If it contained less
   * than 8 bytes of data, fish_sound_identify would simply return
   * FISH_SOUND_ERR_SHORT_IDENTIFY.
   */
  if (decode_serialno == -1 && op->b_o_s && op->bytes >= 8) {
    if (fish_sound_identify (op->packet, op->bytes) != FISH_SOUND_UNKNOWN)
      decode_serialno = serialno;
  }

  /* If this is the track we are decoding, go ahead and decode it */
  if (serialno == decode_serialno) {
    fish_sound_prepare_truncation (fsound, op->granulepos, op->e_o_s);
    fish_sound_decode (fsound, op->packet, op->bytes);
  }

  return 0;
}

int
main (int argc, char ** argv)
{
  OGGZ * oggz;
  FishSound * fsound;
  long n;

  if (argc < 3) {
    printf ("usage: %s infilename outfilename\n", argv[0]);
    printf ("*** FishSound example program. ***\n");
    printf ("Decodes an Ogg FLAC, Speex or Ogg Vorbis file producing a PCM wav file.\n");
    exit (1);
  }

  infilename = argv[1];
  outfilename = argv[2];

  fsound = fish_sound_new (FISH_SOUND_DECODE, NULL);

  fish_sound_set_interleave (fsound, 1);

  fish_sound_set_decoded_float_ilv (fsound, decoded_float, NULL);

  if ((oggz = oggz_open ((char *) infilename, OGGZ_READ)) == NULL) {
    printf ("unable to open file %s\n", infilename);
    exit (1);
  }

  oggz_set_read_callback (oggz, -1, read_packet, fsound);

  while ((n = oggz_read (oggz, 1024)) > 0);

  oggz_close (oggz);

  fish_sound_delete (fsound);
  
  sf_close (sndfile);

  exit (0);
}


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