/* Simple example of using SoX libraries * * Copyright (c) 2007-9 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 "util.h"#include <stdio.h>#include <assert.h> /* * Example of a custom output message handler. */static void output_message(unsigned level, const char *filename, const char *fmt, va_list ap){  char const * const str[] = {"FAIL", "WARN", "INFO", "DBUG"};  if (sox_globals.verbosity >= level) {    char base_name[128];    sox_basename(base_name, sizeof(base_name), filename);    fprintf(stderr, "%s %s: ", str[min(level - 1, 3)], base_name);    vfprintf(stderr, fmt, ap);    fprintf(stderr, "\n");  }} /* * On an alsa capable system, plays an audio file starting 10 seconds in. * Copes with sample-rate and channel change if necessary since its * common for audio drivers to support a subset of rates and channel * counts. * E.g. example3 song2.ogg * * Can easily be changed to work with other audio device drivers supported * by libSoX; e.g. "oss", "ao", "coreaudio", etc. * See the soxformat(7) manual page. */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;  sox_signalinfo_t interm_signal;  char * args[10];   assert(argc == 2);  sox_globals.output_message_handler = output_message;  sox_globals.verbosity = 1;   assert(sox_init() == SOX_SUCCESS);  assert((in = sox_open_read(argv[1], NULL, NULL, NULL)));  /* Change "alsa" in this line to use an alternative audio device driver: */  assert((out= sox_open_write("default", &in->signal, NULL, "alsa", NULL, NULL)));   chain = sox_create_effects_chain(&in->encoding, &out->encoding);   interm_signal = in->signal; /* NB: deep copy */   e = sox_create_effect(sox_find_effect("input"));  args[0] = (char *)in, assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);  assert(sox_add_effect(chain, e, &interm_signal, &in->signal) == SOX_SUCCESS);  free(e);   e = sox_create_effect(sox_find_effect("trim"));  args[0] = "10", assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);  assert(sox_add_effect(chain, e, &interm_signal, &in->signal) == SOX_SUCCESS);  free(e);   if (in->signal.rate != out->signal.rate) {    e = sox_create_effect(sox_find_effect("rate"));    assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);    assert(sox_add_effect(chain, e, &interm_signal, &out->signal) == SOX_SUCCESS);    free(e);  }   if (in->signal.channels != out->signal.channels) {    e = sox_create_effect(sox_find_effect("channels"));    assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);    assert(sox_add_effect(chain, e, &interm_signal, &out->signal) == SOX_SUCCESS);    free(e);  }   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, &interm_signal, &out->signal) == SOX_SUCCESS);  free(e);   sox_flow_effects(chain, NULL, NULL);   sox_delete_effects_chain(chain);  sox_close(out);  sox_close(in);  sox_quit();   return 0;}