cannam@89: /** @file patest_dither.c
cannam@89: 	@ingroup test_src
cannam@89: 	@brief Attempt to hear difference between dithered and non-dithered signal.
cannam@89: 
cannam@89: 	This only has an effect if the native format is 16 bit.
cannam@89: 
cannam@89: 	@author Phil Burk  http://www.softsynth.com
cannam@89: */
cannam@89: /*
cannam@89:  * $Id: patest_dither.c 1368 2008-03-01 00:38:27Z rossb $
cannam@89:  *
cannam@89:  * This program uses the PortAudio Portable Audio Library.
cannam@89:  * For more information see: http://www.portaudio.com
cannam@89:  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
cannam@89:  *
cannam@89:  * Permission is hereby granted, free of charge, to any person obtaining
cannam@89:  * a copy of this software and associated documentation files
cannam@89:  * (the "Software"), to deal in the Software without restriction,
cannam@89:  * including without limitation the rights to use, copy, modify, merge,
cannam@89:  * publish, distribute, sublicense, and/or sell copies of the Software,
cannam@89:  * and to permit persons to whom the Software is furnished to do so,
cannam@89:  * subject to the following conditions:
cannam@89:  *
cannam@89:  * The above copyright notice and this permission notice shall be
cannam@89:  * included in all copies or substantial portions of the Software.
cannam@89:  *
cannam@89:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@89:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@89:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
cannam@89:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
cannam@89:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@89:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@89:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@89:  */
cannam@89: 
cannam@89: /*
cannam@89:  * The text above constitutes the entire PortAudio license; however, 
cannam@89:  * the PortAudio community also makes the following non-binding requests:
cannam@89:  *
cannam@89:  * Any person wishing to distribute modifications to the Software is
cannam@89:  * requested to send the modifications to the original developer so that
cannam@89:  * they can be incorporated into the canonical version. It is also 
cannam@89:  * requested that these non-binding requests be included along with the 
cannam@89:  * license above.
cannam@89:  */
cannam@89: 
cannam@89: #include <stdio.h>
cannam@89: #include <math.h>
cannam@89: 
cannam@89: #include "portaudio.h"
cannam@89: 
cannam@89: #define NUM_SECONDS   (5)
cannam@89: #define SAMPLE_RATE   (44100)
cannam@89: #ifndef M_PI
cannam@89: #define M_PI  (3.14159265)
cannam@89: #endif
cannam@89: #define TABLE_SIZE   (200)
cannam@89: 
cannam@89: typedef struct paTestData
cannam@89: {
cannam@89:     float sine[TABLE_SIZE];
cannam@89:     float amplitude;
cannam@89:     int   left_phase;
cannam@89:     int   right_phase;
cannam@89: }
cannam@89: paTestData;
cannam@89:                          
cannam@89: /* This routine will be called by the PortAudio engine when audio is needed.
cannam@89: ** It may called at interrupt level on some machines so don't do anything
cannam@89: ** that could mess up the system like calling malloc() or free().
cannam@89: */
cannam@89: static int sineCallback( const void *inputBuffer, void *outputBuffer,
cannam@89:                          unsigned long framesPerBuffer,
cannam@89: 			             const PaStreamCallbackTimeInfo *timeInfo,
cannam@89: 			             PaStreamCallbackFlags statusFlags, void *userData )
cannam@89: {
cannam@89:     paTestData *data = (paTestData*)userData;
cannam@89:     float *out = (float*)outputBuffer;
cannam@89:     float amplitude = data->amplitude;
cannam@89:     unsigned int i;
cannam@89:     (void) inputBuffer;
cannam@89:     
cannam@89:     for( i=0; i<framesPerBuffer; i++ )
cannam@89:     {
cannam@89:         *out++ = amplitude * data->sine[data->left_phase];  /* left */
cannam@89:         *out++ = amplitude * data->sine[data->right_phase];  /* right */
cannam@89:         data->left_phase += 1;
cannam@89:         if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
cannam@89:         data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
cannam@89:         if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
cannam@89:     }
cannam@89:     return 0;
cannam@89: }
cannam@89: 
cannam@89: /*****************************************************************************/
cannam@89: /*
cannam@89:     V18 version did not call Pa_Terminate() if Pa_Initialize() failed.
cannam@89:     This V19 version ALWAYS calls Pa_Terminate(). PS.
cannam@89: */
cannam@89: PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude );
cannam@89: PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude )
cannam@89: {
cannam@89:     PaStream*           stream;
cannam@89:     PaStreamParameters  outputParameters;
cannam@89:     PaError             err;
cannam@89: 
cannam@89:     data->left_phase = data->right_phase = 0;
cannam@89:     data->amplitude  = amplitude;
cannam@89: 
cannam@89:     err = Pa_Initialize();
cannam@89:     if (err != paNoError)
cannam@89:         goto done;
cannam@89: 
cannam@89:     outputParameters.device = Pa_GetDefaultOutputDevice();  /* default output device */
cannam@89:     if (outputParameters.device == paNoDevice) {
cannam@89:       fprintf(stderr,"Error: No default output device.\n");
cannam@89:       goto done;
cannam@89:     }
cannam@89:     outputParameters.channelCount = 2;                      /* stereo output */
cannam@89:     outputParameters.hostApiSpecificStreamInfo = NULL;
cannam@89:     outputParameters.sampleFormat = paFloat32;      /* 32 bit floating point output. */
cannam@89:                                                     /* When you change this, also    */
cannam@89:                                                     /* adapt the callback routine!   */ 
cannam@89:     outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )
cannam@89:                                         ->defaultLowOutputLatency;   /* Low latency. */
cannam@89:     err = Pa_OpenStream( &stream,
cannam@89:                          NULL,                              /* No input. */
cannam@89:                          &outputParameters,
cannam@89:                          SAMPLE_RATE,
cannam@89:                          1024,                              /* frames per buffer */
cannam@89:                          flags,
cannam@89:                          sineCallback,
cannam@89:                          (void*)data );
cannam@89:     if (err != paNoError)
cannam@89:         goto done;
cannam@89: 
cannam@89:     err = Pa_StartStream( stream );
cannam@89:     if (err != paNoError)
cannam@89:         goto done;
cannam@89: 
cannam@89:     Pa_Sleep( NUM_SECONDS * 1000 );
cannam@89:     printf("CPULoad = %8.6f\n", Pa_GetStreamCpuLoad(stream));
cannam@89:     
cannam@89:     err = Pa_CloseStream( stream );
cannam@89: done:
cannam@89:     Pa_Sleep( 250 );  /* Just a small silence. */
cannam@89:     Pa_Terminate();
cannam@89:     return err;
cannam@89: }
cannam@89: 
cannam@89: 
cannam@89: /*******************************************************************/
cannam@89: int main(void);
cannam@89: int main(void)
cannam@89: {
cannam@89:     PaError     err;
cannam@89:     paTestData  DATA;
cannam@89:     int         i;
cannam@89:     float       amplitude = 4.0 / (1<<15);
cannam@89:     
cannam@89:     printf("PortAudio Test: output EXTREMELY QUIET sine wave with and without dithering.\n");
cannam@89:     /* initialise sinusoidal wavetable */
cannam@89:     for( i=0; i<TABLE_SIZE; i++ )
cannam@89:     {
cannam@89:         DATA.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
cannam@89:     }
cannam@89:     printf("\nNo treatment..\n"); fflush(stdout);
cannam@89:     err = PlaySine( &DATA, paClipOff | paDitherOff, amplitude );
cannam@89:     if( err < 0 ) goto done;
cannam@89: 
cannam@89:     printf("\nClip..\n");
cannam@89:     fflush(stdout);
cannam@89:     err = PlaySine( &DATA, paDitherOff, amplitude );
cannam@89:     if( err < 0 ) goto done;
cannam@89: 
cannam@89:     printf("\nClip and Dither..\n");
cannam@89:     fflush(stdout);
cannam@89:     err = PlaySine( &DATA, paNoFlag, amplitude );
cannam@89: done:
cannam@89:     if (err)
cannam@89:         {
cannam@89:         fprintf( stderr, "An error occured while using the portaudio stream\n" );
cannam@89:         fprintf( stderr, "Error number: %d\n", err );
cannam@89:         fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
cannam@89:         err = 1; /* Though PlaySine() already called Pa_Terminate(), */
cannam@89:         }        /* we may still call Pa_GetErrorText().             */
cannam@89:     else
cannam@89:         printf("\n(Don't forget to turn the VOLUME DOWN after listening so carefully.)\n");
cannam@89:     return err;  /* 0 or 1. */
cannam@89: }