ref: e60dbd620fdf1ca426d1ff12b212aef45be4d3c2
dir: /src/example1.c/
/* 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>
static sox_format_t * in, * out; /* input and output files */
/* The function that will be called to input samples into the effects chain.
* In this example, we get samples to process from a SoX-openned audio file.
* In a different application, they might be generated or come from a different
* part of the application. */
static int input_drain(
sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp)
{
(void)effp; /* This parameter is not needed in this example */
/* ensure that *osamp is a multiple of the number of channels. */
*osamp -= *osamp % effp->out_signal.channels;
/* Read up to *osamp samples into obuf; store the actual number read
* back to *osamp */
*osamp = sox_read(in, obuf, *osamp);
/* sox_read may return a number that is less than was requested; only if
* 0 samples is returned does it indicate that end-of-file has been reached
* or an error has occurred */
if (!*osamp && in->sox_errno)
fprintf(stderr, "%s: %s\n", in->filename, in->sox_errstr);
return *osamp? SOX_SUCCESS : SOX_EOF;
}
/* The function that will be called to output samples from the effects chain.
* In this example, we store the samples in a SoX-opened audio file.
* In a different application, they might perhaps be analysed in some way,
* or displayed as a wave-form */
static int output_flow(sox_effect_t *effp LSX_UNUSED, sox_sample_t const * ibuf,
sox_sample_t * obuf LSX_UNUSED, size_t * isamp, size_t * osamp)
{
/* Write out *isamp samples */
size_t len = sox_write(out, ibuf, *isamp);
/* len is the number of samples that were actually written out; if this is
* different to *isamp, then something has gone wrong--most often, it's
* out of disc space */
if (len != *isamp) {
fprintf(stderr, "%s: %s\n", out->filename, out->sox_errstr);
return SOX_EOF;
}
/* Outputting is the last `effect' in the effect chain so always passes
* 0 samples on to the next effect (as there isn't one!) */
*osamp = 0;
(void)effp; /* This parameter is not needed in this example */
return SOX_SUCCESS; /* All samples output successfully */
}
/* A `stub' effect handler to handle inputting samples to the effects
* chain; the only function needed for this example is `drain' */
static sox_effect_handler_t const * input_handler(void)
{
static sox_effect_handler_t handler = {
"input", NULL, SOX_EFF_MCHAN, NULL, NULL, NULL, input_drain, NULL, NULL, 0
};
return &handler;
}
/* A `stub' effect handler to handle outputting samples from the effects
* chain; the only function needed for this example is `flow' */
static sox_effect_handler_t const * output_handler(void)
{
static sox_effect_handler_t handler = {
"output", NULL, SOX_EFF_MCHAN, NULL, NULL, output_flow, NULL, NULL, NULL, 0
};
return &handler;
}
/*
* Reads input file, applies vol & flanger effects, stores in output file.
* E.g. example1 monkey.au monkey.aiff
*/
int main(int argc, char * argv[])
{
sox_effects_chain_t * chain;
sox_effect_t * e;
char * vol[] = {"3dB"};
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 have defined an input handler that inputs
* data from an audio file */
e = sox_create_effect(input_handler());
/* 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"));
assert(sox_effect_options(e, 1, vol) == 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 have defined an output handler that outputs
* data to an audio file */
e = sox_create_effect(output_handler());
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;
}