diff src/libsamplerate-0.1.9/examples/varispeed-play.c @ 41:481f5f8c5634

Current libsamplerate source

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libsamplerate-0.1.9/examples/varispeed-play.c	Tue Oct 18 13:24:45 2016 +0100
@@ -0,0 +1,244 @@
+/*
+** Copyright (c) 2002-2016, Erik de Castro Lopo <[e-mail]>
+** All rights reserved.
+**
+** This code is released under 2-clause BSD license. Please see the
+** file at : https://github.com/erikd/libsamplerate/blob/master/COPYING
+*/
+
+#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	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 += 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
+