#include <aubio.h>#include "utils_tests.h" int main (int argc, char **argv){  sint_t err = 0;   if (argc < 2) {    PRINT_ERR("not enough arguments, running tests\n");    err = run_on_default_sink(main);    PRINT_MSG("usage: %s <output_path> [freq] [samplerate]\n", argv[0]);    return err;  }   uint_t samplerate = 44100; // default is the samplerate of input_path  uint_t hop_size = 256;  smpl_t freq = 440.;   char_t *sink_path = argv[1];  if ( argc >= 4 ) samplerate = atoi(argv[3]);  if ( argc >= 3 ) freq = atof(argv[2]);   fvec_t *vec = new_fvec(hop_size);  aubio_sink_t *sink = new_aubio_sink(sink_path, samplerate);   aubio_wavetable_t * wavetable = new_aubio_wavetable (samplerate, hop_size);   // 2 seconds duration, in samples  uint_t duration = 2 * samplerate;   uint_t n_frames = 0;  uint_t write = 0;   aubio_wavetable_play (wavetable);  aubio_wavetable_set_freq ( wavetable, freq );   uint_t region = 0;   do {    if ( n_frames > duration / 3 && region < 1) {      aubio_wavetable_stop (wavetable);      region++;    }    if ( n_frames > 2 * duration / 3 && region < 2) {      aubio_wavetable_play (wavetable);      aubio_wavetable_set_freq ( wavetable, freq  / 2.);      region++;    }    if (duration - n_frames < hop_size * 2 ) {      aubio_wavetable_stop( wavetable );    }    if (duration - n_frames < hop_size ) {      write = duration - n_frames;    } else {      write = hop_size;    }    aubio_wavetable_do (wavetable, vec, vec);    aubio_sink_do(sink, vec, write);    n_frames += hop_size;  } while ( n_frames <= duration );   del_aubio_wavetable (wavetable);  del_aubio_sink(sink);  del_fvec(vec);  aubio_cleanup();   return 0;}