forked from Mirrors/freeswitch
f210c27f43
git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3761 d0543943-73ff-0310-b7d9-9358b9ac24b2
132 lines
4.4 KiB
C
132 lines
4.4 KiB
C
/*
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** Copyright (C) 2001-2005 Erik de Castro Lopo <erikd@mega-nerd.com>
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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/* Include this header file to use functions from libsndfile. */
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#include <sndfile.h>
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/* This will be the length of the buffer used to hold.frames while
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** we process them.
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*/
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#define BUFFER_LEN 1024
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/* libsndfile can handle more than 6 channels but we'll restrict it to 6. */
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#define MAX_CHANNELS 6
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/* Function prototype. */
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static void process_data (double *data, int count, int channels) ;
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int
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main (void)
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{ /* This is a buffer of double precision floating point values
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** which will hold our data while we process it.
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*/
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static double data [BUFFER_LEN] ;
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/* A SNDFILE is very much like a FILE in the Standard C library. The
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** sf_open function return an SNDFILE* pointer when they sucessfully
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** open the specified file.
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*/
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SNDFILE *infile, *outfile ;
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/* A pointer to an SF_INFO stutct is passed to sf_open.
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** On read, the library fills this struct with information about the file.
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** On write, the struct must be filled in before calling sf_open.
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*/
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SF_INFO sfinfo ;
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int readcount ;
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const char *infilename = "input.wav" ;
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const char *outfilename = "output.wav" ;
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/* Here's where we open the input file. We pass sf_open the file name and
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** a pointer to an SF_INFO struct.
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** On successful open, sf_open returns a SNDFILE* pointer which is used
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** for all subsequent operations on that file.
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** If an error occurs during sf_open, the function returns a NULL pointer.
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**
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** If you are trying to open a raw headerless file you will need to set the
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** format and channels fields of sfinfo before calling sf_open(). For
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** instance to open a raw 16 bit stereo PCM file you would need the following
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** two lines:
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**
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** sfinfo.format = SF_FORMAT_RAW | SF_FORMAT_PCM_16 ;
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** sfinfo.channels = 2 ;
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*/
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if (! (infile = sf_open (infilename, SFM_READ, &sfinfo)))
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{ /* Open failed so print an error message. */
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printf ("Not able to open input file %s.\n", infilename) ;
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/* Print the error message from libsndfile. */
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puts (sf_strerror (NULL)) ;
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return 1 ;
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} ;
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if (sfinfo.channels > MAX_CHANNELS)
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{ printf ("Not able to process more than %d channels\n", MAX_CHANNELS) ;
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return 1 ;
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} ;
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/* Open the output file. */
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if (! (outfile = sf_open (outfilename, SFM_WRITE, &sfinfo)))
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{ printf ("Not able to open output file %s.\n", outfilename) ;
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puts (sf_strerror (NULL)) ;
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return 1 ;
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} ;
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/* While there are.frames in the input file, read them, process
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** them and write them to the output file.
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*/
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while ((readcount = sf_read_double (infile, data, BUFFER_LEN)))
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{ process_data (data, readcount, sfinfo.channels) ;
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sf_write_double (outfile, data, readcount) ;
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} ;
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/* Close input and output files. */
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sf_close (infile) ;
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sf_close (outfile) ;
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return 0 ;
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} /* main */
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static void
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process_data (double *data, int count, int channels)
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{ double channel_gain [MAX_CHANNELS] = { 0.5, 0.8, 0.1, 0.4, 0.4, 0.9 } ;
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int k, chan ;
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/* Process the data here.
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** If the soundfile contains more then 1 channel you need to take care of
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** the data interleaving youself.
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** Current we just apply a channel dependant gain.
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*/
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for (chan = 0 ; chan < channels ; chan ++)
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for (k = chan ; k < count ; k+= channels)
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data [k] *= channel_gain [chan] ;
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return ;
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} /* process_data */
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/*
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** Do not edit or modify anything in this comment block.
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** The arch-tag line is a file identity tag for the GNU Arch
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** revision control system.
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**
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** arch-tag: de9fdd1e-b807-41ef-9d51-075ba383e536
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*/
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