ref: 2c47fa8aa8447ea97cfd66da200caffaf12f5b37
dir: /examples/varispeed-play.c/
/*
** Copyright (C) 2002-2008 Erik de Castro Lopo <erikd@mega-nerd.com>
**
** 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "config.h"
#include <float_cast.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 INPUT_FRAMES 100
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAGIC_NUMBER ((int) ('S' << 16) + ('R' << 8) + ('C'))
#ifndef M_PI
#define M_PI 3.14159265358979323846264338
#endif
typedef struct
{ int magic ;
SNDFILE *sndfile ;
SF_INFO sfinfo ;
SRC_STATE *src_state ;
SRC_DATA src_data ;
int freq_point ;
int buffer_out_start, buffer_out_end ;
float buffer_in [BUFFER_LEN] ;
float buffer_out [BUFFER_LEN] ;
} CALLBACK_DATA ;
static int varispeed_get_data (CALLBACK_DATA *data, float *samples, int frames) ;
static void varispeed_play (const char *filename, int converter) ;
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)
{ CALLBACK_DATA *data ;
AUDIO_OUT *audio_out ;
int error ;
/* Allocate memory for the callback data. */
if ((data = calloc (1, sizeof (CALLBACK_DATA))) == NULL)
{ printf ("\n\n%s:%d Calloc failed!\n", __FILE__, __LINE__) ;
exit (1) ;
} ;
data->magic = MAGIC_NUMBER ;
if ((data->sndfile = sf_open (filename, SFM_READ, &data->sfinfo)) == NULL)
{ puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
/* Initialize the sample rate converter. */
if ((data->src_state = src_new (converter, data->sfinfo.channels, &error)) == 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->sfinfo.channels, data->sfinfo.samplerate)) == NULL)
{ printf ("\n\nError : audio_open () failed.\n") ;
exit (1) ;
} ;
/* Set up sample rate converter info. */
data->src_data.end_of_input = 0 ; /* Set this later. */
/* Start with zero to force load in while loop. */
data->src_data.input_frames = 0 ;
data->src_data.data_in = data->buffer_in ;
/* Start with output frames also zero. */
data->src_data.output_frames_gen = 0 ;
data->buffer_out_start = data->buffer_out_end = 0 ;
data->src_data.src_ratio = 1.0 ;
/* 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->sndfile) ;
src_delete (data->src_state) ;
free (data) ;
} /* varispeed_play */
/*==============================================================================
*/
static int
varispeed_get_data (CALLBACK_DATA *data, float *samples, int frames)
{ int error, readframes, frame_count, direct_out ;
if (data->magic != MAGIC_NUMBER)
{ printf ("\n\n%s:%d Eeeek, something really bad happened!\n", __FILE__, __LINE__) ;
exit (1) ;
} ;
frame_count = 0 ;
if (data->buffer_out_start < data->buffer_out_end)
{ frame_count = MIN (data->buffer_out_end - data->buffer_out_start, frames) ;
memcpy (samples, data->buffer_out + data->sfinfo.channels * data->buffer_out_start, data->sfinfo.channels * frame_count * sizeof (float)) ;
data->buffer_out_start += frame_count ;
} ;
data->buffer_out_start = data->buffer_out_end = 0 ;
while (frame_count < frames)
{
/* Read INPUT_FRAMES frames worth looping at end of file. */
for (readframes = 0 ; readframes < INPUT_FRAMES ; )
{ sf_count_t position ;
readframes += sf_readf_float (data->sndfile, data->buffer_in + data->sfinfo.channels * readframes, INPUT_FRAMES - readframes) ;
position = sf_seek (data->sndfile, 0, SEEK_CUR) ;
if (position < 0 || position == data->sfinfo.frames)
sf_seek (data->sndfile, 0, SEEK_SET) ;
} ;
data->src_data.input_frames = readframes ;
data->src_data.src_ratio = 1.0 - 0.5 * sin (data->freq_point * 2 * M_PI / 20000) ;
data->freq_point ++ ;
direct_out = (data->src_data.src_ratio * readframes < frames - frame_count) ? 1 : 0 ;
if (direct_out)
{ data->src_data.data_out = samples + frame_count * data->sfinfo.channels ;
data->src_data.output_frames = frames - frame_count ;
}
else
{ data->src_data.data_out = data->buffer_out ;
data->src_data.output_frames = BUFFER_LEN / data->sfinfo.channels ;
} ;
if ((error = src_process (data->src_state, &data->src_data)))
{ printf ("\nError : %s\n\n", src_strerror (error)) ;
exit (1) ;
} ;
if (direct_out)
{ frame_count += data->src_data.output_frames_gen ;
continue ;
} ;
memcpy (samples + frame_count * data->sfinfo.channels, data->buffer_out, (frames - frame_count) * data->sfinfo.channels * sizeof (float)) ;
data->buffer_out_start = frames - frame_count ;
data->buffer_out_end = data->src_data.output_frames_gen ;
frame_count += frames - frame_count ;
} ;
return frame_count ;
} /* 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