src/example0.c

   1 /* Simple example of using SoX libraries
   2  *
   3  * Copyright (c) 2007-8 robs@users.sourceforge.net
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  13  * Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifdef NDEBUG /* N.B. assert used with active statements so enable always. */
  21 #undef NDEBUG /* Must undef above assert.h or other that might include it. */
  22 #endif
  23
  24 #include "sox.h"
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <assert.h>
  28
  29 /*
  30  * Reads input file, applies vol & flanger effects, stores in output file.
  31  * E.g. example1 monkey.au monkey.aiff
  32  */
  33 int main(int argc, char * argv[])
  34 {
  35   static sox_format_t * in, * out; /* input and output files */
  36   sox_effects_chain_t * chain;
  37   sox_effect_t * e;
  38   char * args[10];
  39
  40   assert(argc == 3);
  41
  42   /* All libSoX applications must start by initialising the SoX library */
  43   assert(sox_init() == SOX_SUCCESS);
  44
  45   /* Open the input file (with default parameters) */
  46   assert((in = sox_open_read(argv[1], NULL, NULL, NULL)));
  47
  48   /* Open the output file; we must specify the output signal characteristics.
  49    * Since we are using only simple effects, they are the same as the input
  50    * file characteristics */
  51   assert((out = sox_open_write(argv[2], &in->signal, NULL, NULL, NULL, NULL)));
  52
  53   /* Create an effects chain; some effects need to know about the input
  54    * or output file encoding so we provide that information here */
  55   chain = sox_create_effects_chain(&in->encoding, &out->encoding);
  56
  57   /* The first effect in the effect chain must be something that can source
  58    * samples; in this case, we use the built-in handler that inputs
  59    * data from an audio file */
  60   e = sox_create_effect(sox_find_effect("input"));
  61   args[0] = (char *)in, assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);
  62   /* This becomes the first `effect' in the chain */
  63   assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);
  64   free(e);
  65
  66   /* Create the `vol' effect, and initialise it with the desired parameters: */
  67   e = sox_create_effect(sox_find_effect("vol"));
  68   args[0] = "3dB", assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);
  69   /* Add the effect to the end of the effects processing chain: */
  70   assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);
  71   free(e);
  72
  73   /* Create the `flanger' effect, and initialise it with default parameters: */
  74   e = sox_create_effect(sox_find_effect("flanger"));
  75   assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);
  76   /* Add the effect to the end of the effects processing chain: */
  77   assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);
  78   free(e);
  79
  80   /* The last effect in the effect chain must be something that only consumes
  81    * samples; in this case, we use the built-in handler that outputs
  82    * data to an audio file */
  83   e = sox_create_effect(sox_find_effect("output"));
  84   args[0] = (char *)out, assert(sox_effect_options(e, 1, args) == SOX_SUCCESS);
  85   assert(sox_add_effect(chain, e, &in->signal, &in->signal) == SOX_SUCCESS);
  86   free(e);
  87
  88   /* Flow samples through the effects processing chain until EOF is reached */
  89   sox_flow_effects(chain, NULL, NULL);
  90
  91   /* All done; tidy up: */
  92   sox_delete_effects_chain(chain);
  93   sox_close(out);
  94   sox_close(in);
  95   sox_quit();
  96   return 0;
  97 }