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/*
* $Id: patest_dither.c,v 1.1.1.1 2003-05-09 16:03:56 ggeiger Exp $
* patest_dither.c
* Attempt to hear difference between dithered and non-dithered signal.
* This only has an effect if the native format is 16 bit.
*
* Author: Phil Burk http://www.softsynth.com
*
* This program uses the PortAudio Portable Audio Library.
* For more information see: http://www.portaudio.com
* Copyright (c) 1999-2000 Ross Bencina and Phil Burk
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* Any person wishing to distribute modifications to the Software is
* requested to send the modifications to the original developer so that
* they can be incorporated into the canonical version.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include <stdio.h>
#include <math.h>
#include "portaudio.h"
#define NUM_SECONDS (4)
#define SAMPLE_RATE (44100)
#ifndef M_PI
#define M_PI (3.14159265)
#endif
#define TABLE_SIZE (200)
typedef struct paTestData
{
float sine[TABLE_SIZE];
float amplitude;
int left_phase;
int right_phase;
}
paTestData;
PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude );
static int sineCallback( void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer,
PaTimestamp outTime, void *userData );
/* This routine will be called by the PortAudio engine when audio is needed.
** It may called at interrupt level on some machines so don't do anything
** that could mess up the system like calling malloc() or free().
*/
static int sineCallback( void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer,
PaTimestamp outTime, void *userData )
{
paTestData *data = (paTestData*)userData;
float *out = (float*)outputBuffer;
float amplitude = data->amplitude;
unsigned int i;
(void) outTime;
(void) inputBuffer;
for( i=0; i<framesPerBuffer; i++ )
{
*out++ = amplitude * data->sine[data->left_phase]; /* left */
*out++ = amplitude * data->sine[data->right_phase]; /* right */
data->left_phase += 1;
if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
}
return 0;
}
/*******************************************************************/
int main(void);
int main(void)
{
PaError err;
paTestData DATA;
int i;
float amplitude = 32.0 / (1<<15);
printf("PortAudio Test: output EXTREMELY QUIET sine wave with and without dithering.\n");
/* initialise sinusoidal wavetable */
for( i=0; i<TABLE_SIZE; i++ )
{
DATA.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
}
printf("\nNo treatment..\n"); fflush(stdout);
err = PlaySine( &DATA, paClipOff | paDitherOff, amplitude );
if( err < 0 ) goto error;
printf("\nClip.\n");
fflush(stdout);
err = PlaySine( &DATA, paDitherOff, amplitude );
if( err < 0 ) goto error;
printf("\nClip and Dither.\n");
fflush(stdout);
err = PlaySine( &DATA, paNoFlag, amplitude );
if( err < 0 ) goto error;
return 0;
error:
fprintf( stderr, "An error occured while using the portaudio stream\n" );
fprintf( stderr, "Error number: %d\n", err );
fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
return -1;
}
/*****************************************************************************/
PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude )
{
PortAudioStream *stream;
PaError err;
data->left_phase = data->right_phase = 0;
data->amplitude = amplitude;
err = Pa_Initialize();
if( err != paNoError ) goto error;
err = Pa_OpenStream(
&stream,
paNoDevice,/* default input device */
0, /* no input */
paFloat32, /* 32 bit floating point input */
NULL,
Pa_GetDefaultOutputDeviceID(), /* default output device */
2, /* stereo output */
paFloat32, /* 32 bit floating point output */
NULL,
SAMPLE_RATE,
1024,
0, /* number of buffers, if zero then use default minimum */
flags, /* we won't output out of range samples so don't bother clipping them */
sineCallback,
(void *)data );
if( err != paNoError ) goto error;
err = Pa_StartStream( stream );
if( err != paNoError ) goto error;
Pa_Sleep( NUM_SECONDS * 1000 );
printf("CPULoad = %8.6f\n", Pa_GetCPULoad( stream ) );
err = Pa_CloseStream( stream );
if( err != paNoError ) goto error;
Pa_Terminate();
return paNoError;
error:
return err;
}
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