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/*
** Copyright (C) 2001-2005 Erik de Castro Lopo <erikd@mega-nerd.com>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
/* Include this header file to use functions from libsndfile. */
#include <sndfile.h>
/* This will be the length of the buffer used to hold.frames while
** we process them.
*/
#define BUFFER_LEN 1024
/* libsndfile can handle more than 6 channels but we'll restrict it to 6. */
#define MAX_CHANNELS 6
/* Function prototype. */
static void process_data (double *data, int count, int channels) ;
int
main (void)
{ /* This is a buffer of double precision floating point values
** which will hold our data while we process it.
*/
static double data [BUFFER_LEN] ;
/* A SNDFILE is very much like a FILE in the Standard C library. The
** sf_open function return an SNDFILE* pointer when they sucessfully
** open the specified file.
*/
SNDFILE *infile, *outfile ;
/* A pointer to an SF_INFO stutct is passed to sf_open.
** On read, the library fills this struct with information about the file.
** On write, the struct must be filled in before calling sf_open.
*/
SF_INFO sfinfo ;
int readcount ;
const char *infilename = "input.wav" ;
const char *outfilename = "output.wav" ;
/* Here's where we open the input file. We pass sf_open the file name and
** a pointer to an SF_INFO struct.
** On successful open, sf_open returns a SNDFILE* pointer which is used
** for all subsequent operations on that file.
** If an error occurs during sf_open, the function returns a NULL pointer.
**
** If you are trying to open a raw headerless file you will need to set the
** format and channels fields of sfinfo before calling sf_open(). For
** instance to open a raw 16 bit stereo PCM file you would need the following
** two lines:
**
** sfinfo.format = SF_FORMAT_RAW | SF_FORMAT_PCM_16 ;
** sfinfo.channels = 2 ;
*/
if (! (infile = sf_open (infilename, SFM_READ, &sfinfo)))
{ /* Open failed so print an error message. */
printf ("Not able to open input file %s.\n", infilename) ;
/* Print the error message from libsndfile. */
puts (sf_strerror (NULL)) ;
return 1 ;
} ;
if (sfinfo.channels > MAX_CHANNELS)
{ printf ("Not able to process more than %d channels\n", MAX_CHANNELS) ;
return 1 ;
} ;
/* Open the output file. */
if (! (outfile = sf_open (outfilename, SFM_WRITE, &sfinfo)))
{ printf ("Not able to open output file %s.\n", outfilename) ;
puts (sf_strerror (NULL)) ;
return 1 ;
} ;
/* While there are.frames in the input file, read them, process
** them and write them to the output file.
*/
while ((readcount = sf_read_double (infile, data, BUFFER_LEN)))
{ process_data (data, readcount, sfinfo.channels) ;
sf_write_double (outfile, data, readcount) ;
} ;
/* Close input and output files. */
sf_close (infile) ;
sf_close (outfile) ;
return 0 ;
} /* main */
static void
process_data (double *data, int count, int channels)
{ double channel_gain [MAX_CHANNELS] = { 0.5, 0.8, 0.1, 0.4, 0.4, 0.9 } ;
int k, chan ;
/* Process the data here.
** If the soundfile contains more then 1 channel you need to take care of
** the data interleaving youself.
** Current we just apply a channel dependant gain.
*/
for (chan = 0 ; chan < channels ; chan ++)
for (k = chan ; k < count ; k+= channels)
data [k] *= channel_gain [chan] ;
return ;
} /* process_data */
/*
** Do not edit or modify anything in this comment block.
** The arch-tag line is a file identity tag for the GNU Arch
** revision control system.
**
** arch-tag: de9fdd1e-b807-41ef-9d51-075ba383e536
*/
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