/* Simple example of using SoX libraries * * Copyright (c) 2007-8 robs@users.sourceforge.net * * 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., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifdef NDEBUG /* N.B. assert used with active statements so enable always. */#undef NDEBUG /* Must undef above assert.h or other that might include it. */#endif #include "sox.h"#include <stdlib.h>#include <stdio.h>#include <assert.h> /* * Reads input file, applies vol & flanger effects, stores in output file. * E.g. example1 monkey.au monkey.aiff */int main(int argc, char * argv[]){  static sox_format_t * in, * out; /* input and output files */  sox_effects_chain_t * chain;  sox_effect_t * e;  char * args[10];   assert(argc == 3);   /* All libSoX applications must start by initialising the SoX library */  assert(sox_init() == SOX_SUCCESS);   /* Open the input file (with default parameters) */  assert((in = sox_open_read(argv[1], NULL, NULL, NULL)));   /* Open the output file; we must specify the output signal characteristics.   * Since we are using only simple effects, they are the same as the input   * file characteristics */  assert((out = sox_open_write(argv[2], &in->signal, NULL, NULL, NULL, NULL)));   /* Create an effects chain; some effects need to know about the input   * or output file encoding so we provide that information here */  chain = sox_create_effects_chain(&in->encoding, &out->encoding);   /* The first effect in the effect chain must be something that can source   * samples; in this case, we use the built-in handler that inputs   * data from an audio file */  e = sox_create_effect(sox_find_effect("input"));  args[0] = (char *)in, assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);  /* This becomes the first `effect' in the chain */  assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);  free(e);   /* Create the `vol' effect, and initialise it with the desired parameters: */  e = sox_create_effect(sox_find_effect("vol"));  args[0] = "3dB", assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);  /* Add the effect to the end of the effects processing chain: */  assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);  free(e);   /* Create the `flanger' effect, and initialise it with default parameters: */  e = sox_create_effect(sox_find_effect("flanger"));  assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);  /* Add the effect to the end of the effects processing chain: */  assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);  free(e);   /* The last effect in the effect chain must be something that only consumes   * samples; in this case, we use the built-in handler that outputs   * data to an audio file */  e = sox_create_effect(sox_find_effect("output"));  args[0] = (char *)out, assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);  assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);  free(e);   /* Flow samples through the effects processing chain until EOF is reached */  sox_flow_effects(chain, NULL, NULL);   /* All done; tidy up: */  sox_delete_effects_chain(chain);  sox_close(out);  sox_close(in);  sox_quit();  return 0;}