ref: aa6f7617d9297b9fe90863dcf02e9d0cbcb2daad
dir: /examples/varispeed-play.c/
/*
** Copyright (c) 2002-2016, Erik de Castro Lopo <erikd@mega-nerd.com>
** All rights reserved.
**
** This code is released under 2-clause BSD license. Please see the
** file at : https://github.com/libsndfile/libsamplerate/blob/master/COPYING
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <math.h>
#include "src_config.h"
#if (HAVE_SNDFILE)
#include <samplerate.h>
#include <sndfile.h>
#include "audio_out.h"
#define ARRAY_LEN(x) ((int) (sizeof (x) / sizeof ((x) [0])))
#define BUFFER_LEN 4096
#define VARISPEED_BLOCK_LEN 64
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define SRC_MAGIC ((int) ('S' << 16) + ('R' << 8) + ('C'))
#define SNDFILE_MAGIC ((int) ('s' << 24) + ('n' << 20) + ('d' << 16) + ('f' << 12) + ('i' << 8) + ('l' << 4) + 'e')
#ifndef M_PI
#define M_PI 3.14159265358979323846264338
#endif
typedef struct
{ int magic ;
SNDFILE *sndfile ;
SF_INFO sfinfo ;
float buffer [BUFFER_LEN] ;
} SNDFILE_CB_DATA ;
typedef struct
{ int magic ;
SNDFILE_CB_DATA sf ;
int freq_point ;
SRC_STATE *src_state ;
} SRC_CB_DATA ;
static int varispeed_get_data (SRC_CB_DATA *data, float *samples, int frames) ;
static void varispeed_play (const char *filename, int converter) ;
static long src_input_callback (void *cb_data, float **data) ;
int
main (int argc, char *argv [])
{ const char *cptr, *progname, *filename ;
int k, converter ;
converter = SRC_SINC_FASTEST ;
progname = argv [0] ;
if ((cptr = strrchr (progname, '/')) != NULL)
progname = cptr + 1 ;
if ((cptr = strrchr (progname, '\\')) != NULL)
progname = cptr + 1 ;
printf ("\n"
" %s\n"
"\n"
" This is a demo program which plays the given file at a slowly \n"
" varying speed. Lots of fun with drum loops and full mixes.\n"
"\n"
" It uses Secret Rabbit Code (aka libsamplerate) to perform the \n"
" vari-speeding and libsndfile for file I/O.\n"
"\n", progname) ;
if (argc == 2)
filename = argv [1] ;
else if (argc == 4 && strcmp (argv [1], "-c") == 0)
{ filename = argv [3] ;
converter = atoi (argv [2]) ;
}
else
{ printf (" Usage :\n\n %s [-c <number>] <input file>\n\n", progname) ;
puts (
" The optional -c argument allows the converter type to be chosen from\n"
" the following list :"
"\n"
) ;
for (k = 0 ; (cptr = src_get_name (k)) != NULL ; k++)
printf (" %d : %s\n", k, cptr) ;
puts ("") ;
exit (1) ;
} ;
varispeed_play (filename, converter) ;
return 0 ;
} /* main */
/*==============================================================================
*/
static void
varispeed_play (const char *filename, int converter)
{ SRC_CB_DATA data ;
AUDIO_OUT *audio_out ;
int error ;
memset (&data, 0, sizeof (data)) ;
data.magic = SRC_MAGIC ;
data.sf.magic = SNDFILE_MAGIC ;
if ((data.sf.sndfile = sf_open (filename, SFM_READ, &data.sf.sfinfo)) == NULL)
{ puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
/* Initialize the sample rate converter. */
if ((data.src_state = src_callback_new (src_input_callback, converter, data.sf.sfinfo.channels, &error, &data.sf)) == NULL)
{ printf ("\n\nError : src_new() failed : %s.\n\n", src_strerror (error)) ;
exit (1) ;
} ;
printf (
" Playing : %s\n"
" Converter : %s\n"
"\n"
" Press <control-c> to exit.\n"
"\n",
filename, src_get_name (converter)) ;
if ((audio_out = audio_open (data.sf.sfinfo.channels, data.sf.sfinfo.samplerate)) == NULL)
{ printf ("\n\nError : audio_open () failed.\n") ;
exit (1) ;
} ;
/* Pass the data and the callbacl function to audio_play */
audio_play ((get_audio_callback_t) varispeed_get_data, audio_out, &data) ;
/* Cleanup */
audio_close (audio_out) ;
sf_close (data.sf.sndfile) ;
src_delete (data.src_state) ;
} /* varispeed_play */
static long
src_input_callback (void *cb_data, float **audio)
{ SNDFILE_CB_DATA * data = (SNDFILE_CB_DATA *) cb_data ;
const int input_frames = ARRAY_LEN (data->buffer) / data->sfinfo.channels ;
int read_frames ;
if (data->magic != SNDFILE_MAGIC)
{ printf ("\n\n%s:%d Eeeek, something really bad happened!\n", __FILE__, __LINE__) ;
exit (1) ;
} ;
for (read_frames = 0 ; read_frames < input_frames ; )
{ sf_count_t position ;
read_frames += (int) sf_readf_float (data->sndfile, data->buffer + read_frames * data->sfinfo.channels, input_frames - read_frames) ;
position = sf_seek (data->sndfile, 0, SEEK_CUR) ;
if (position < 0 || position == data->sfinfo.frames)
sf_seek (data->sndfile, 0, SEEK_SET) ;
} ;
*audio = & (data->buffer [0]) ;
return input_frames ;
} /* src_input_callback */
/*==============================================================================
*/
static int
varispeed_get_data (SRC_CB_DATA *data, float *samples, int out_frames)
{ float *output ;
int rc, out_frame_count ;
if (data->magic != SRC_MAGIC)
{ printf ("\n\n%s:%d Eeeek, something really bad happened!\n", __FILE__, __LINE__) ;
exit (1) ;
} ;
for (out_frame_count = 0 ; out_frame_count < out_frames ; out_frame_count += VARISPEED_BLOCK_LEN)
{ double src_ratio = 1.0 - 0.5 * sin (data->freq_point * 2 * M_PI / 20000) ;
data->freq_point ++ ;
output = samples + out_frame_count * data->sf.sfinfo.channels ;
if ((rc = src_callback_read (data->src_state, src_ratio, VARISPEED_BLOCK_LEN, output)) < VARISPEED_BLOCK_LEN)
{ printf ("\nError : src_callback_read short output (%d instead of %d)\n\n", rc, VARISPEED_BLOCK_LEN) ;
exit (1) ;
} ;
} ;
return out_frames ;
} /* varispeed_get_data */
/*==============================================================================
*/
#else /* (HAVE_SNFILE == 0) */
/* Alternative main function when libsndfile is not available. */
int
main (void)
{ puts (
"\n"
"****************************************************************\n"
" This example program was compiled without libsndfile \n"
" (http://www.zip.com.au/~erikd/libsndfile/).\n"
" It is therefore completely broken and non-functional.\n"
"****************************************************************\n"
"\n"
) ;
return 0 ;
} /* main */
#endif