187 lines
6.7 KiB
C
187 lines
6.7 KiB
C
/** @file patest_dither.c
|
|
@ingroup test_src
|
|
@brief 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
|
|
*/
|
|
/*
|
|
* $Id: patest_dither.c 1097 2006-08-26 08:27:53Z rossb $
|
|
*
|
|
* 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.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* The text above constitutes the entire PortAudio license; however,
|
|
* the PortAudio community also makes the following non-binding requests:
|
|
*
|
|
* 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. It is also
|
|
* requested that these non-binding requests be included along with the
|
|
* license above.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
|
|
#include "portaudio.h"
|
|
|
|
#define NUM_SECONDS (5)
|
|
#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;
|
|
|
|
/* 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( const void *inputBuffer, void *outputBuffer,
|
|
unsigned long framesPerBuffer,
|
|
const PaStreamCallbackTimeInfo *timeInfo,
|
|
PaStreamCallbackFlags statusFlags, void *userData )
|
|
{
|
|
paTestData *data = (paTestData*)userData;
|
|
float *out = (float*)outputBuffer;
|
|
float amplitude = data->amplitude;
|
|
unsigned int i;
|
|
(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;
|
|
}
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
V18 version did not call Pa_Terminate() if Pa_Initialize() failed.
|
|
This V19 version ALWAYS calls Pa_Terminate(). PS.
|
|
*/
|
|
PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude );
|
|
PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude )
|
|
{
|
|
PaStream* stream;
|
|
PaStreamParameters outputParameters;
|
|
PaError err;
|
|
|
|
data->left_phase = data->right_phase = 0;
|
|
data->amplitude = amplitude;
|
|
|
|
err = Pa_Initialize();
|
|
if (err != paNoError)
|
|
goto done;
|
|
|
|
outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
|
|
outputParameters.channelCount = 2; /* stereo output */
|
|
outputParameters.hostApiSpecificStreamInfo = NULL;
|
|
outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */
|
|
/* When you change this, also */
|
|
/* adapt the callback routine! */
|
|
outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )
|
|
->defaultLowOutputLatency; /* Low latency. */
|
|
err = Pa_OpenStream( &stream,
|
|
NULL, /* No input. */
|
|
&outputParameters,
|
|
SAMPLE_RATE,
|
|
1024, /* frames per buffer */
|
|
flags,
|
|
sineCallback,
|
|
(void*)data );
|
|
if (err != paNoError)
|
|
goto done;
|
|
|
|
err = Pa_StartStream( stream );
|
|
if (err != paNoError)
|
|
goto done;
|
|
|
|
Pa_Sleep( NUM_SECONDS * 1000 );
|
|
printf("CPULoad = %8.6f\n", Pa_GetStreamCpuLoad(stream));
|
|
|
|
err = Pa_CloseStream( stream );
|
|
done:
|
|
Pa_Sleep( 250 ); /* Just a small silence. */
|
|
Pa_Terminate();
|
|
return err;
|
|
}
|
|
|
|
|
|
/*******************************************************************/
|
|
int main(void);
|
|
int main(void)
|
|
{
|
|
PaError err;
|
|
paTestData DATA;
|
|
int i;
|
|
float amplitude = 4.0 / (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 done;
|
|
|
|
printf("\nClip..\n");
|
|
fflush(stdout);
|
|
err = PlaySine( &DATA, paDitherOff, amplitude );
|
|
if( err < 0 ) goto done;
|
|
|
|
printf("\nClip and Dither..\n");
|
|
fflush(stdout);
|
|
err = PlaySine( &DATA, paNoFlag, amplitude );
|
|
done:
|
|
if (err)
|
|
{
|
|
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 ) );
|
|
err = 1; /* Though PlaySine() already called Pa_Terminate(), */
|
|
} /* we may still call Pa_GetErrorText(). */
|
|
else
|
|
printf("\n(Don't forget to turn the VOLUME DOWN after listening so carefully.)\n");
|
|
return err; /* 0 or 1. */
|
|
}
|