Chris@39: /** @file paqa_latency.c
Chris@39: 	@ingroup qa_src
Chris@39: 	@brief Test latency estimates.
Chris@39: 	@author Ross Bencina <rossb@audiomulch.com>
Chris@39:     @author Phil Burk <philburk@softsynth.com>
Chris@39: */
Chris@39: /*
Chris@39:  * $Id: patest_sine.c 1368 2008-03-01 00:38:27Z rossb $
Chris@39:  *
Chris@39:  * This program uses the PortAudio Portable Audio Library.
Chris@39:  * For more information see: http://www.portaudio.com/
Chris@39:  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
Chris@39:  *
Chris@39:  * Permission is hereby granted, free of charge, to any person obtaining
Chris@39:  * a copy of this software and associated documentation files
Chris@39:  * (the "Software"), to deal in the Software without restriction,
Chris@39:  * including without limitation the rights to use, copy, modify, merge,
Chris@39:  * publish, distribute, sublicense, and/or sell copies of the Software,
Chris@39:  * and to permit persons to whom the Software is furnished to do so,
Chris@39:  * subject to the following conditions:
Chris@39:  *
Chris@39:  * The above copyright notice and this permission notice shall be
Chris@39:  * included in all copies or substantial portions of the Software.
Chris@39:  *
Chris@39:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@39:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@39:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
Chris@39:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
Chris@39:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@39:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@39:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@39:  */
Chris@39: 
Chris@39: /*
Chris@39:  * The text above constitutes the entire PortAudio license; however, 
Chris@39:  * the PortAudio community also makes the following non-binding requests:
Chris@39:  *
Chris@39:  * Any person wishing to distribute modifications to the Software is
Chris@39:  * requested to send the modifications to the original developer so that
Chris@39:  * they can be incorporated into the canonical version. It is also 
Chris@39:  * requested that these non-binding requests be included along with the 
Chris@39:  * license above.
Chris@39:  */
Chris@39: #include <stdio.h>
Chris@39: #include <math.h>
Chris@39: #include "portaudio.h"
Chris@39: #include "loopback/src/qa_tools.h"
Chris@39: 
Chris@39: #define NUM_SECONDS   (5)
Chris@39: #define SAMPLE_RATE   (44100)
Chris@39: #define FRAMES_PER_BUFFER  (64)
Chris@39: 
Chris@39: #ifndef M_PI
Chris@39: #define M_PI  (3.14159265)
Chris@39: #endif
Chris@39: 
Chris@39: #define TABLE_SIZE   (200)
Chris@39: typedef struct
Chris@39: {
Chris@39:     float sine[TABLE_SIZE];
Chris@39:     int left_phase;
Chris@39:     int right_phase;
Chris@39:     char message[20];
Chris@39:     int minFramesPerBuffer;
Chris@39:     int maxFramesPerBuffer;
Chris@39:     int callbackCount;
Chris@39:     PaTime minDeltaDacTime;
Chris@39:     PaTime maxDeltaDacTime;
Chris@39:     PaStreamCallbackTimeInfo previousTimeInfo;
Chris@39: }
Chris@39: paTestData;
Chris@39: 
Chris@39: /* Used to tally the results of the QA tests. */
Chris@39: int g_testsPassed = 0;
Chris@39: int g_testsFailed = 0;
Chris@39: 
Chris@39: /* This routine will be called by the PortAudio engine when audio is needed.
Chris@39: ** It may called at interrupt level on some machines so don't do anything
Chris@39: ** that could mess up the system like calling malloc() or free().
Chris@39: */
Chris@39: static int patestCallback( const void *inputBuffer, void *outputBuffer,
Chris@39:                             unsigned long framesPerBuffer,
Chris@39:                             const PaStreamCallbackTimeInfo* timeInfo,
Chris@39:                             PaStreamCallbackFlags statusFlags,
Chris@39:                             void *userData )
Chris@39: {
Chris@39:     paTestData *data = (paTestData*)userData;
Chris@39:     float *out = (float*)outputBuffer;
Chris@39:     unsigned long i;
Chris@39: 
Chris@39:     (void) timeInfo; /* Prevent unused variable warnings. */
Chris@39:     (void) statusFlags;
Chris@39:     (void) inputBuffer;
Chris@39:     
Chris@39:     if( data->minFramesPerBuffer > framesPerBuffer )
Chris@39:     {
Chris@39:         data->minFramesPerBuffer = framesPerBuffer;
Chris@39:     }
Chris@39:     if( data->maxFramesPerBuffer < framesPerBuffer )
Chris@39:     {
Chris@39:         data->maxFramesPerBuffer = framesPerBuffer;
Chris@39:     }
Chris@39:     
Chris@39:     /* Measure min and max output time stamp delta. */
Chris@39:     if( data->callbackCount > 0 )
Chris@39:     {
Chris@39:         PaTime delta = timeInfo->outputBufferDacTime - data->previousTimeInfo.outputBufferDacTime;
Chris@39:         if( data->minDeltaDacTime > delta )
Chris@39:         {
Chris@39:             data->minDeltaDacTime = delta;
Chris@39:         }
Chris@39:         if( data->maxDeltaDacTime < delta )
Chris@39:         {
Chris@39:             data->maxDeltaDacTime = delta;
Chris@39:         }
Chris@39:     }
Chris@39:     data->previousTimeInfo = *timeInfo;
Chris@39:     
Chris@39:     for( i=0; i<framesPerBuffer; i++ )
Chris@39:     {
Chris@39:         *out++ = data->sine[data->left_phase];  /* left */
Chris@39:         *out++ = data->sine[data->right_phase];  /* right */
Chris@39:         data->left_phase += 1;
Chris@39:         if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
Chris@39:         data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
Chris@39:         if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
Chris@39:     }
Chris@39:     
Chris@39:     data->callbackCount += 1;
Chris@39:     return paContinue;
Chris@39: }
Chris@39: 
Chris@39: PaError paqaCheckLatency( PaStreamParameters *outputParamsPtr, 
Chris@39:                          paTestData *dataPtr, double sampleRate, unsigned long framesPerBuffer )
Chris@39: {
Chris@39:     PaError err;
Chris@39:     PaStream *stream;
Chris@39:     const PaStreamInfo* streamInfo;
Chris@39: 
Chris@39:     dataPtr->minFramesPerBuffer = 9999999;
Chris@39:     dataPtr->maxFramesPerBuffer = 0;
Chris@39:     dataPtr->minDeltaDacTime = 9999999.0;
Chris@39:     dataPtr->maxDeltaDacTime = 0.0;
Chris@39:     dataPtr->callbackCount = 0;
Chris@39:     
Chris@39:     printf("Stream parameter: suggestedOutputLatency = %g\n", outputParamsPtr->suggestedLatency );
Chris@39:     if( framesPerBuffer == paFramesPerBufferUnspecified ){
Chris@39:         printf("Stream parameter: user framesPerBuffer = paFramesPerBufferUnspecified\n" );
Chris@39:     }else{
Chris@39:         printf("Stream parameter: user framesPerBuffer = %lu\n", framesPerBuffer );
Chris@39:     }
Chris@39:     err = Pa_OpenStream(
Chris@39:                         &stream,
Chris@39:                         NULL, /* no input */
Chris@39:                         outputParamsPtr,
Chris@39:                         sampleRate,
Chris@39:                         framesPerBuffer,
Chris@39:                         paClipOff,      /* we won't output out of range samples so don't bother clipping them */
Chris@39:                         patestCallback,
Chris@39:                         dataPtr );
Chris@39:     if( err != paNoError ) goto error1;
Chris@39:     
Chris@39:     streamInfo = Pa_GetStreamInfo( stream );
Chris@39:     printf("Stream info: inputLatency  = %g\n", streamInfo->inputLatency );
Chris@39:     printf("Stream info: outputLatency = %g\n", streamInfo->outputLatency );
Chris@39: 
Chris@39:     err = Pa_StartStream( stream );
Chris@39:     if( err != paNoError ) goto error2;
Chris@39: 
Chris@39:     printf("Play for %d seconds.\n", NUM_SECONDS );
Chris@39:     Pa_Sleep( NUM_SECONDS * 1000 );
Chris@39:     
Chris@39:     printf("  minFramesPerBuffer = %4d\n", dataPtr->minFramesPerBuffer );
Chris@39:     printf("  maxFramesPerBuffer = %4d\n", dataPtr->maxFramesPerBuffer );
Chris@39:     printf("  minDeltaDacTime = %f\n", dataPtr->minDeltaDacTime );
Chris@39:     printf("  maxDeltaDacTime = %f\n", dataPtr->maxDeltaDacTime );
Chris@39: 
Chris@39:     err = Pa_StopStream( stream );
Chris@39:     if( err != paNoError ) goto error2;
Chris@39: 
Chris@39:     err = Pa_CloseStream( stream );
Chris@39:     Pa_Sleep( 1 * 1000 );
Chris@39: 
Chris@39:     
Chris@39:     printf("-------------------------------------\n");
Chris@39:     return err;
Chris@39: error2:
Chris@39:     Pa_CloseStream( stream );
Chris@39: error1:
Chris@39:     printf("-------------------------------------\n");
Chris@39:     return err;
Chris@39: }
Chris@39: 
Chris@39: 
Chris@39: /*******************************************************************/
Chris@39: static int paqaNoopCallback( const void *inputBuffer, void *outputBuffer,
Chris@39:                           unsigned long framesPerBuffer,
Chris@39:                           const PaStreamCallbackTimeInfo* timeInfo,
Chris@39:                           PaStreamCallbackFlags statusFlags,
Chris@39:                           void *userData )
Chris@39: {
Chris@39:     (void)inputBuffer;
Chris@39:     (void)outputBuffer;
Chris@39:     (void)framesPerBuffer;
Chris@39:     (void)timeInfo;
Chris@39:     (void)statusFlags;
Chris@39:     (void)userData;
Chris@39:     return paContinue;
Chris@39: }
Chris@39: 
Chris@39: /*******************************************************************/
Chris@39: static int paqaCheckMultipleSuggested( PaDeviceIndex deviceIndex, int isInput )
Chris@39: {
Chris@39:     int i;
Chris@39:     int numLoops = 10;
Chris@39:     PaError err;
Chris@39:     PaStream *stream;
Chris@39:     PaStreamParameters streamParameters;
Chris@39:     const PaStreamInfo* streamInfo;
Chris@39:     double lowLatency;
Chris@39:     double highLatency;
Chris@39:     double finalLatency;
Chris@39:     double sampleRate = SAMPLE_RATE;
Chris@39:     const PaDeviceInfo *pdi = Pa_GetDeviceInfo( deviceIndex );
Chris@39:     double previousLatency = 0.0;
Chris@39:     int numChannels = 1;
Chris@39:     float toleranceRatio = 1.0;
Chris@39: 
Chris@39:     printf("------------------------ paqaCheckMultipleSuggested - %s\n",
Chris@39:            (isInput ? "INPUT" : "OUTPUT") );
Chris@39:     if( isInput )
Chris@39:     {
Chris@39:         lowLatency = pdi->defaultLowInputLatency;
Chris@39:         highLatency = pdi->defaultHighInputLatency;
Chris@39:         numChannels = (pdi->maxInputChannels < 2) ? 1 : 2;
Chris@39:     }
Chris@39:     else
Chris@39:     {
Chris@39:         lowLatency = pdi->defaultLowOutputLatency;
Chris@39:         highLatency = pdi->defaultHighOutputLatency;
Chris@39:         numChannels = (pdi->maxOutputChannels < 2) ? 1 : 2;
Chris@39:     }
Chris@39:     streamParameters.channelCount = numChannels;
Chris@39:     streamParameters.device = deviceIndex;
Chris@39:     streamParameters.hostApiSpecificStreamInfo = NULL;
Chris@39:     streamParameters.sampleFormat = paFloat32;
Chris@39:     sampleRate = pdi->defaultSampleRate;
Chris@39:     
Chris@39:     printf(" lowLatency  = %g\n", lowLatency );
Chris@39:     printf(" highLatency = %g\n", highLatency );
Chris@39:     printf(" numChannels = %d\n", numChannels );
Chris@39:     printf(" sampleRate  = %g\n", sampleRate );
Chris@39:     
Chris@39:     if( (highLatency - lowLatency) < 0.001 )
Chris@39:     {
Chris@39:         numLoops = 1;
Chris@39:     }
Chris@39: 
Chris@39:     for( i=0; i<numLoops; i++ )
Chris@39:     {   
Chris@39:         if( numLoops == 1 )
Chris@39:             streamParameters.suggestedLatency = lowLatency;
Chris@39:         else
Chris@39:             streamParameters.suggestedLatency = lowLatency + ((highLatency - lowLatency) * i /(numLoops - 1));
Chris@39:         
Chris@39:         printf("   suggestedLatency[%d] = %6.4f\n", i, streamParameters.suggestedLatency );
Chris@39:     
Chris@39:         err = Pa_OpenStream(
Chris@39:                             &stream,
Chris@39:                             (isInput ? &streamParameters : NULL),
Chris@39:                             (isInput ? NULL : &streamParameters),
Chris@39:                             sampleRate,
Chris@39:                             paFramesPerBufferUnspecified,
Chris@39:                             paClipOff,      /* we won't output out of range samples so don't bother clipping them */
Chris@39:                             paqaNoopCallback,
Chris@39:                             NULL );
Chris@39:         if( err != paNoError ) goto error;
Chris@39:         
Chris@39:         streamInfo = Pa_GetStreamInfo( stream );
Chris@39:         
Chris@39:         err = Pa_CloseStream( stream );
Chris@39:         
Chris@39:         if( isInput )
Chris@39:         {
Chris@39:             finalLatency = streamInfo->inputLatency;
Chris@39:         }
Chris@39:         else
Chris@39:         {
Chris@39:             finalLatency = streamInfo->outputLatency;
Chris@39:         }
Chris@39:         printf("          finalLatency = %6.4f\n", finalLatency );
Chris@39:         /* For the default low & high latency values, expect quite close; for other requested
Chris@39:          * values, at worst the next power-of-2 may result (eg 513 -> 1024) */
Chris@39:         toleranceRatio = ( (i == 0) || (i == ( numLoops - 1 )) ) ? 0.1 : 1.0;
Chris@39:         QA_ASSERT_CLOSE( "final latency should be close to suggested latency",
Chris@39:                         streamParameters.suggestedLatency, finalLatency, (streamParameters.suggestedLatency * toleranceRatio) );
Chris@39:         if( i == 0 )
Chris@39:         {
Chris@39:             previousLatency = finalLatency;
Chris@39:         }
Chris@39:     }
Chris@39: 
Chris@39:     if( numLoops > 1 )
Chris@39:     {
Chris@39:         QA_ASSERT_TRUE( " final latency should increase with suggested latency", (finalLatency > previousLatency) );
Chris@39:     }
Chris@39: 
Chris@39:     return 0;
Chris@39: error:
Chris@39:     return -1;
Chris@39: }
Chris@39: 
Chris@39: /*******************************************************************/
Chris@39: static int paqaVerifySuggestedLatency( void )
Chris@39: {
Chris@39:     PaDeviceIndex id;
Chris@39:     int result = 0;
Chris@39:     const PaDeviceInfo *pdi;
Chris@39:     int numDevices = Pa_GetDeviceCount();
Chris@39:     
Chris@39:     printf("\n ------------------------ paqaVerifySuggestedLatency\n");
Chris@39:     for( id=0; id<numDevices; id++ )            /* Iterate through all devices. */
Chris@39:     {
Chris@39:         pdi = Pa_GetDeviceInfo( id );
Chris@39:         printf("\nUsing device #%d: '%s' (%s)\n", id, pdi->name, Pa_GetHostApiInfo(pdi->hostApi)->name);
Chris@39:         if( pdi->maxOutputChannels > 0 )
Chris@39:         {
Chris@39:             if( paqaCheckMultipleSuggested( id, 0 ) < 0 )
Chris@39:             {
Chris@39:                 printf("OUTPUT CHECK FAILED !!! #%d: '%s'\n", id, pdi->name);
Chris@39:                 result -= 1;
Chris@39:             }
Chris@39:         }
Chris@39:         if( pdi->maxInputChannels > 0 )
Chris@39:         {
Chris@39:             if( paqaCheckMultipleSuggested( id, 1 ) < 0 )
Chris@39:             {
Chris@39:                 printf("INPUT CHECK FAILED !!! #%d: '%s'\n", id, pdi->name);
Chris@39:                 result -= 1;
Chris@39:             }
Chris@39:         }
Chris@39:     }
Chris@39:     return result;
Chris@39: }
Chris@39: 
Chris@39: /*******************************************************************/
Chris@39: static int paqaVerifyDeviceInfoLatency( void )
Chris@39: {
Chris@39:     PaDeviceIndex id;
Chris@39:     const PaDeviceInfo *pdi;
Chris@39:     int numDevices = Pa_GetDeviceCount();
Chris@39:     
Chris@39:     printf("\n ------------------------ paqaVerifyDeviceInfoLatency\n");
Chris@39:     for( id=0; id<numDevices; id++ ) /* Iterate through all devices. */
Chris@39:     {
Chris@39:         pdi = Pa_GetDeviceInfo( id );
Chris@39:         printf("Using device #%d: '%s' (%s)\n", id, pdi->name, Pa_GetHostApiInfo(pdi->hostApi)->name);
Chris@39:         if( pdi->maxOutputChannels > 0 )
Chris@39:         {
Chris@39:             printf("  Output defaultLowOutputLatency  = %f seconds\n", pdi->defaultLowOutputLatency);
Chris@39:             printf("  Output defaultHighOutputLatency = %f seconds\n", pdi->defaultHighOutputLatency);
Chris@39:             QA_ASSERT_TRUE( "defaultLowOutputLatency should be > 0", (pdi->defaultLowOutputLatency > 0.0) );
Chris@39:             QA_ASSERT_TRUE( "defaultHighOutputLatency should be > 0", (pdi->defaultHighOutputLatency > 0.0) );
Chris@39:             QA_ASSERT_TRUE( "defaultHighOutputLatency should be >= Low", (pdi->defaultHighOutputLatency >= pdi->defaultLowOutputLatency) );
Chris@39:         }
Chris@39:         if( pdi->maxInputChannels > 0 )
Chris@39:         {
Chris@39:             printf("  Input defaultLowInputLatency  = %f seconds\n", pdi->defaultLowInputLatency);
Chris@39:             printf("  Input defaultHighInputLatency = %f seconds\n", pdi->defaultHighInputLatency);
Chris@39:             QA_ASSERT_TRUE( "defaultLowInputLatency should be > 0", (pdi->defaultLowInputLatency > 0.0) );
Chris@39:             QA_ASSERT_TRUE( "defaultHighInputLatency should be > 0", (pdi->defaultHighInputLatency > 0.0) );
Chris@39:             QA_ASSERT_TRUE( "defaultHighInputLatency should be >= Low", (pdi->defaultHighInputLatency >= pdi->defaultLowInputLatency) );
Chris@39:         }
Chris@39:     }
Chris@39:     return 0;
Chris@39: error:
Chris@39:     return -1;
Chris@39: }
Chris@39: 
Chris@39: 
Chris@39: 
Chris@39: /*******************************************************************/
Chris@39: int main(void);
Chris@39: int main(void)
Chris@39: {
Chris@39:     PaStreamParameters outputParameters;
Chris@39:     PaError err;
Chris@39:     paTestData data;
Chris@39:     const PaDeviceInfo *deviceInfo;
Chris@39:     int i;
Chris@39:     int framesPerBuffer;
Chris@39:     double sampleRate = SAMPLE_RATE;
Chris@39:     
Chris@39:     printf("\nPortAudio QA: investigate output latency.\n");
Chris@39: 
Chris@39:     /* initialise sinusoidal wavetable */
Chris@39:     for( i=0; i<TABLE_SIZE; i++ )
Chris@39:     {
Chris@39:         data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
Chris@39:     }
Chris@39:     data.left_phase = data.right_phase = 0;
Chris@39:     
Chris@39:     err = Pa_Initialize();
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     /* Run self tests. */
Chris@39:     if( paqaVerifyDeviceInfoLatency() < 0 ) goto error;
Chris@39:     
Chris@39:     if( paqaVerifySuggestedLatency() < 0 ) goto error;
Chris@39:     
Chris@39:     outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
Chris@39:     if (outputParameters.device == paNoDevice) {
Chris@39:       fprintf(stderr,"Error: No default output device.\n");
Chris@39:       goto error;
Chris@39:     }
Chris@39: 
Chris@39:     printf("\n\nNow running Audio Output Tests...\n");
Chris@39:     printf("-------------------------------------\n");
Chris@39: 
Chris@39:     outputParameters.channelCount = 2;       /* stereo output */
Chris@39:     outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output */
Chris@39:     deviceInfo = Pa_GetDeviceInfo( outputParameters.device );
Chris@39:     printf("Using device #%d: '%s' (%s)\n", outputParameters.device, deviceInfo->name, Pa_GetHostApiInfo(deviceInfo->hostApi)->name);
Chris@39:     printf("Device info: defaultLowOutputLatency  = %f seconds\n", deviceInfo->defaultLowOutputLatency);
Chris@39:     printf("Device info: defaultHighOutputLatency = %f seconds\n", deviceInfo->defaultHighOutputLatency);
Chris@39:     sampleRate = deviceInfo->defaultSampleRate;
Chris@39:     printf("Sample Rate for following tests: %g\n", sampleRate);
Chris@39:     outputParameters.hostApiSpecificStreamInfo = NULL;
Chris@39:     printf("-------------------------------------\n");
Chris@39: 
Chris@39:     // Try to use a small buffer that is smaller than we think the device can handle.
Chris@39:     // Try to force combining multiple user buffers into a host buffer.
Chris@39:     printf("------------- Try a very small buffer.\n");
Chris@39:     framesPerBuffer = 9;
Chris@39:     outputParameters.suggestedLatency = deviceInfo->defaultLowOutputLatency;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, framesPerBuffer );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     printf("------------- 64 frame buffer with 1.1 * defaultLow latency.\n");
Chris@39:     framesPerBuffer = 64;
Chris@39:     outputParameters.suggestedLatency = deviceInfo->defaultLowOutputLatency * 1.1;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, framesPerBuffer );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     // Try to create a huge buffer that is bigger than the allowed device maximum.
Chris@39:     printf("------------- Try a huge buffer.\n");
Chris@39:     framesPerBuffer = 16*1024;
Chris@39:     outputParameters.suggestedLatency = ((double)framesPerBuffer) / sampleRate; // approximate
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, framesPerBuffer );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     printf("------------- Try suggestedLatency = 0.0\n");
Chris@39:     outputParameters.suggestedLatency = 0.0;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, paFramesPerBufferUnspecified );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     printf("------------- Try suggestedLatency = defaultLowOutputLatency\n");
Chris@39:     outputParameters.suggestedLatency = deviceInfo->defaultLowOutputLatency;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, paFramesPerBufferUnspecified );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     printf("------------- Try suggestedLatency = defaultHighOutputLatency\n");
Chris@39:     outputParameters.suggestedLatency = deviceInfo->defaultHighOutputLatency;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, paFramesPerBufferUnspecified );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     printf("------------- Try suggestedLatency = defaultHighOutputLatency * 4\n");
Chris@39:     outputParameters.suggestedLatency = deviceInfo->defaultHighOutputLatency * 4;
Chris@39:     err = paqaCheckLatency( &outputParameters, &data, sampleRate, paFramesPerBufferUnspecified );
Chris@39:     if( err != paNoError ) goto error;
Chris@39:     
Chris@39:     Pa_Terminate();
Chris@39:     printf("SUCCESS - test finished.\n");
Chris@39:     return err;
Chris@39:     
Chris@39: error:
Chris@39:     Pa_Terminate();
Chris@39:     fprintf( stderr, "ERROR - test failed.\n" );
Chris@39:     fprintf( stderr, "Error number: %d\n", err );
Chris@39:     fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
Chris@39:     return err;
Chris@39: }