make_sine.c

Audacity是一款用於錄音和編輯聲音的、免費的開放源碼軟體。它可以執行於Mac OS X、Microsoft Windows、GNU/Linux和其它作業系統

/*
** Copyright (C) 1999-2004 Erik de Castro Lopo <[e-mail]>
**
** 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	<string.h>
#include	<math.h>

#include	<sndfile.h>

#ifndef		M_PI
#define		M_PI		3.14159265358979323846264338
#endif

#define		SAMPLE_RATE			44100
#define		SAMPLE_COUNT		(SAMPLE_RATE * 4)	/* 4 seconds */
#define		AMPLITUDE			(1.0 * 0x7F000000)
#define		LEFT_FREQ			(344.0 / SAMPLE_RATE)
#define		RIGHT_FREQ			(466.0 / SAMPLE_RATE)

int
main (void)
{	SNDFILE	*file ;
	SF_INFO	sfinfo ;
	int		k ;
	int	*buffer ;

	if (! (buffer = malloc (2 * SAMPLE_COUNT * sizeof (int))))
	{	printf ("Malloc failed.\n") ;
		exit (0) ;
		} ;

	memset (&sfinfo, 0, sizeof (sfinfo)) ;

	sfinfo.samplerate	= SAMPLE_RATE ;
	sfinfo.frames		= SAMPLE_COUNT ;
	sfinfo.channels		= 2 ;
	sfinfo.format		= (SF_FORMAT_WAV | SF_FORMAT_PCM_24) ;

	if (! (file = sf_open ("sine.wav", SFM_WRITE, &sfinfo)))
	{	printf ("Error : Not able to open output file.\n") ;
		return 1 ;
		} ;

	if (sfinfo.channels == 1)
	{	for (k = 0 ; k < SAMPLE_COUNT ; k++)
			buffer [k] = AMPLITUDE * sin (LEFT_FREQ * 2 * k * M_PI) ;
		}
	else if (sfinfo.channels == 2)
	{	for (k = 0 ; k < SAMPLE_COUNT ; k++)
		{	buffer [2 * k] = AMPLITUDE * sin (LEFT_FREQ * 2 * k * M_PI) ;
			buffer [2 * k + 1] = AMPLITUDE * sin (RIGHT_FREQ * 2 * k * M_PI) ;
			} ;
		}
	else
	{	printf ("makesine can only generate mono or stereo files.\n") ;
		exit (1) ;
		} ;

	if (sf_write_int (file, buffer, sfinfo.channels * SAMPLE_COUNT) !=
											sfinfo.channels * SAMPLE_COUNT)
		puts (sf_strerror (file)) ;

	sf_close (file) ;
	return	 0 ;
} /* main */

/*
** Do not edit or modify anything in this comment block.
** The arch-tag line is a file identity tag for the GNU Arch
** revision control system.
**
** arch-tag: fd945a2c-a306-49ef-a262-6336ced15246
*/