ref: 6308ce1a99c2c202cddc05e309bbb3bee7be73d2
dir: /examples/varispeed-play.c/
/* ** Copyright (c) 2002-2016, Erik de Castro Lopo <[email protected]> ** 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 <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 += 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