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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


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