Chris@4: /** @file patest_dither.c
Chris@4: 	@ingroup test_src
Chris@4: 	@brief Attempt to hear difference between dithered and non-dithered signal.
Chris@4: 
Chris@4: 	This only has an effect if the native format is 16 bit.
Chris@4: 
Chris@4: 	@author Phil Burk  http://www.softsynth.com
Chris@4: */
Chris@4: /*
Chris@4:  * $Id: patest_dither.c 1368 2008-03-01 00:38:27Z rossb $
Chris@4:  *
Chris@4:  * This program uses the PortAudio Portable Audio Library.
Chris@4:  * For more information see: http://www.portaudio.com
Chris@4:  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
Chris@4:  *
Chris@4:  * Permission is hereby granted, free of charge, to any person obtaining
Chris@4:  * a copy of this software and associated documentation files
Chris@4:  * (the "Software"), to deal in the Software without restriction,
Chris@4:  * including without limitation the rights to use, copy, modify, merge,
Chris@4:  * publish, distribute, sublicense, and/or sell copies of the Software,
Chris@4:  * and to permit persons to whom the Software is furnished to do so,
Chris@4:  * subject to the following conditions:
Chris@4:  *
Chris@4:  * The above copyright notice and this permission notice shall be
Chris@4:  * included in all copies or substantial portions of the Software.
Chris@4:  *
Chris@4:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@4:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@4:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
Chris@4:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
Chris@4:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@4:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@4:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@4:  */
Chris@4: 
Chris@4: /*
Chris@4:  * The text above constitutes the entire PortAudio license; however, 
Chris@4:  * the PortAudio community also makes the following non-binding requests:
Chris@4:  *
Chris@4:  * Any person wishing to distribute modifications to the Software is
Chris@4:  * requested to send the modifications to the original developer so that
Chris@4:  * they can be incorporated into the canonical version. It is also 
Chris@4:  * requested that these non-binding requests be included along with the 
Chris@4:  * license above.
Chris@4:  */
Chris@4: 
Chris@4: #include <stdio.h>
Chris@4: #include <math.h>
Chris@4: 
Chris@4: #include "portaudio.h"
Chris@4: 
Chris@4: #define NUM_SECONDS   (5)
Chris@4: #define SAMPLE_RATE   (44100)
Chris@4: #ifndef M_PI
Chris@4: #define M_PI  (3.14159265)
Chris@4: #endif
Chris@4: #define TABLE_SIZE   (200)
Chris@4: 
Chris@4: typedef struct paTestData
Chris@4: {
Chris@4:     float sine[TABLE_SIZE];
Chris@4:     float amplitude;
Chris@4:     int   left_phase;
Chris@4:     int   right_phase;
Chris@4: }
Chris@4: paTestData;
Chris@4:                          
Chris@4: /* This routine will be called by the PortAudio engine when audio is needed.
Chris@4: ** It may called at interrupt level on some machines so don't do anything
Chris@4: ** that could mess up the system like calling malloc() or free().
Chris@4: */
Chris@4: static int sineCallback( const void *inputBuffer, void *outputBuffer,
Chris@4:                          unsigned long framesPerBuffer,
Chris@4: 			             const PaStreamCallbackTimeInfo *timeInfo,
Chris@4: 			             PaStreamCallbackFlags statusFlags, void *userData )
Chris@4: {
Chris@4:     paTestData *data = (paTestData*)userData;
Chris@4:     float *out = (float*)outputBuffer;
Chris@4:     float amplitude = data->amplitude;
Chris@4:     unsigned int i;
Chris@4:     (void) inputBuffer;
Chris@4:     
Chris@4:     for( i=0; i<framesPerBuffer; i++ )
Chris@4:     {
Chris@4:         *out++ = amplitude * data->sine[data->left_phase];  /* left */
Chris@4:         *out++ = amplitude * data->sine[data->right_phase];  /* right */
Chris@4:         data->left_phase += 1;
Chris@4:         if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
Chris@4:         data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
Chris@4:         if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
Chris@4:     }
Chris@4:     return 0;
Chris@4: }
Chris@4: 
Chris@4: /*****************************************************************************/
Chris@4: /*
Chris@4:     V18 version did not call Pa_Terminate() if Pa_Initialize() failed.
Chris@4:     This V19 version ALWAYS calls Pa_Terminate(). PS.
Chris@4: */
Chris@4: PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude );
Chris@4: PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude )
Chris@4: {
Chris@4:     PaStream*           stream;
Chris@4:     PaStreamParameters  outputParameters;
Chris@4:     PaError             err;
Chris@4: 
Chris@4:     data->left_phase = data->right_phase = 0;
Chris@4:     data->amplitude  = amplitude;
Chris@4: 
Chris@4:     err = Pa_Initialize();
Chris@4:     if (err != paNoError)
Chris@4:         goto done;
Chris@4: 
Chris@4:     outputParameters.device = Pa_GetDefaultOutputDevice();  /* default output device */
Chris@4:     if (outputParameters.device == paNoDevice) {
Chris@4:       fprintf(stderr,"Error: No default output device.\n");
Chris@4:       goto done;
Chris@4:     }
Chris@4:     outputParameters.channelCount = 2;                      /* stereo output */
Chris@4:     outputParameters.hostApiSpecificStreamInfo = NULL;
Chris@4:     outputParameters.sampleFormat = paFloat32;      /* 32 bit floating point output. */
Chris@4:                                                     /* When you change this, also    */
Chris@4:                                                     /* adapt the callback routine!   */ 
Chris@4:     outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )
Chris@4:                                         ->defaultLowOutputLatency;   /* Low latency. */
Chris@4:     err = Pa_OpenStream( &stream,
Chris@4:                          NULL,                              /* No input. */
Chris@4:                          &outputParameters,
Chris@4:                          SAMPLE_RATE,
Chris@4:                          1024,                              /* frames per buffer */
Chris@4:                          flags,
Chris@4:                          sineCallback,
Chris@4:                          (void*)data );
Chris@4:     if (err != paNoError)
Chris@4:         goto done;
Chris@4: 
Chris@4:     err = Pa_StartStream( stream );
Chris@4:     if (err != paNoError)
Chris@4:         goto done;
Chris@4: 
Chris@4:     Pa_Sleep( NUM_SECONDS * 1000 );
Chris@4:     printf("CPULoad = %8.6f\n", Pa_GetStreamCpuLoad(stream));
Chris@4:     
Chris@4:     err = Pa_CloseStream( stream );
Chris@4: done:
Chris@4:     Pa_Sleep( 250 );  /* Just a small silence. */
Chris@4:     Pa_Terminate();
Chris@4:     return err;
Chris@4: }
Chris@4: 
Chris@4: 
Chris@4: /*******************************************************************/
Chris@4: int main(void);
Chris@4: int main(void)
Chris@4: {
Chris@4:     PaError     err;
Chris@4:     paTestData  DATA;
Chris@4:     int         i;
Chris@4:     float       amplitude = 4.0 / (1<<15);
Chris@4:     
Chris@4:     printf("PortAudio Test: output EXTREMELY QUIET sine wave with and without dithering.\n");
Chris@4:     /* initialise sinusoidal wavetable */
Chris@4:     for( i=0; i<TABLE_SIZE; i++ )
Chris@4:     {
Chris@4:         DATA.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
Chris@4:     }
Chris@4:     printf("\nNo treatment..\n"); fflush(stdout);
Chris@4:     err = PlaySine( &DATA, paClipOff | paDitherOff, amplitude );
Chris@4:     if( err < 0 ) goto done;
Chris@4: 
Chris@4:     printf("\nClip..\n");
Chris@4:     fflush(stdout);
Chris@4:     err = PlaySine( &DATA, paDitherOff, amplitude );
Chris@4:     if( err < 0 ) goto done;
Chris@4: 
Chris@4:     printf("\nClip and Dither..\n");
Chris@4:     fflush(stdout);
Chris@4:     err = PlaySine( &DATA, paNoFlag, amplitude );
Chris@4: done:
Chris@4:     if (err)
Chris@4:         {
Chris@4:         fprintf( stderr, "An error occured while using the portaudio stream\n" );
Chris@4:         fprintf( stderr, "Error number: %d\n", err );
Chris@4:         fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
Chris@4:         err = 1; /* Though PlaySine() already called Pa_Terminate(), */
Chris@4:         }        /* we may still call Pa_GetErrorText().             */
Chris@4:     else
Chris@4:         printf("\n(Don't forget to turn the VOLUME DOWN after listening so carefully.)\n");
Chris@4:     return err;  /* 0 or 1. */
Chris@4: }