/* Simple example of using SoX libraries * * Copyright (c) 2007-14 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> /* * Shows how to explicitly specify output file signal and encoding attributes. *  * The example converts a given input file of any type to mono mu-law at 8kHz * sampling-rate (providing that this is supported by the given output file * type). * * For example: * *   sox -r 16k -n input.wav synth 8 sin 0:8k sin 8k:0 gain -1 *   ./example6 input.wav output.wav *   soxi input.wav output.wav * * gives: * * Input File     : 'input.wav' * Channels       : 2 * Sample Rate    : 16000 * Precision      : 32-bit * Duration       : 00:00:08.00 = 128000 samples ~ 600 CDDA sectors * File Size      : 1.02M * Bit Rate       : 1.02M * Sample Encoding: 32-bit Signed Integer PCM * * Input File     : 'output.wav' * Channels       : 1 * Sample Rate    : 8000 * Precision      : 14-bit * Duration       : 00:00:08.00 = 64000 samples ~ 600 CDDA sectors * File Size      : 64.1k * Bit Rate       : 64.1k * Sample Encoding: 8-bit u-law */ 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];  sox_signalinfo_t interm_signal; /* @ intermediate points in the chain. */  sox_encodinginfo_t out_encoding = {    SOX_ENCODING_ULAW,    8,    0,    sox_option_default,    sox_option_default,    sox_option_default,    sox_false  };  sox_signalinfo_t out_signal = {    8000,    1,    0,    0,    NULL  };   assert(argc == 3);  assert(sox_init() == SOX_SUCCESS);  assert((in = sox_open_read(argv[1], NULL, NULL, NULL)));  assert((out = sox_open_write(argv[2], &out_signal, &out_encoding, NULL, 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);   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;}