Chris@4: /** @file pa_minlat.c Chris@4: @ingroup test_src Chris@4: @brief Experiment with different numbers of buffers to determine the Chris@4: minimum latency for a computer. Chris@4: @author Phil Burk http://www.softsynth.com Chris@4: */ Chris@4: /* Chris@4: * $Id: pa_minlat.c 1612 2011-02-28 23:56:48Z philburk $ 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 Chris@4: #include Chris@4: #include Chris@4: #include Chris@4: #include "portaudio.h" Chris@4: Chris@4: #ifndef M_PI Chris@4: #define M_PI (3.14159265) Chris@4: #endif Chris@4: #define TWOPI (M_PI * 2.0) Chris@4: Chris@4: #define DEFAULT_BUFFER_SIZE (32) Chris@4: Chris@4: typedef struct Chris@4: { Chris@4: double left_phase; Chris@4: double right_phase; Chris@4: } Chris@4: paTestData; Chris@4: Chris@4: /* Very simple synthesis routine to generate two sine waves. */ Chris@4: static int paminlatCallback( const void *inputBuffer, void *outputBuffer, Chris@4: unsigned long framesPerBuffer, Chris@4: const PaStreamCallbackTimeInfo* timeInfo, Chris@4: PaStreamCallbackFlags statusFlags, Chris@4: void *userData ) Chris@4: { Chris@4: paTestData *data = (paTestData*)userData; Chris@4: float *out = (float*)outputBuffer; Chris@4: unsigned int i; Chris@4: double left_phaseInc = 0.02; Chris@4: double right_phaseInc = 0.06; Chris@4: Chris@4: double left_phase = data->left_phase; Chris@4: double right_phase = data->right_phase; Chris@4: Chris@4: for( i=0; i TWOPI ) left_phase -= TWOPI; Chris@4: *out++ = (float) sin( left_phase ); Chris@4: Chris@4: right_phase += right_phaseInc; Chris@4: if( right_phase > TWOPI ) right_phase -= TWOPI; Chris@4: *out++ = (float) sin( right_phase ); Chris@4: } Chris@4: Chris@4: data->left_phase = left_phase; Chris@4: data->right_phase = right_phase; Chris@4: return 0; Chris@4: } Chris@4: Chris@4: int main( int argc, char **argv ); Chris@4: int main( int argc, char **argv ) Chris@4: { Chris@4: PaStreamParameters outputParameters; Chris@4: PaStream *stream; Chris@4: PaError err; Chris@4: paTestData data; Chris@4: int go; Chris@4: int outLatency = 0; Chris@4: int minLatency = DEFAULT_BUFFER_SIZE * 2; Chris@4: int framesPerBuffer; Chris@4: double sampleRate = 44100.0; Chris@4: char str[256]; Chris@4: char *line; Chris@4: Chris@4: printf("pa_minlat - Determine minimum latency for your computer.\n"); Chris@4: printf(" usage: pa_minlat {userBufferSize}\n"); Chris@4: printf(" for example: pa_minlat 64\n"); Chris@4: printf("Adjust your stereo until you hear a smooth tone in each speaker.\n"); Chris@4: printf("Then try to find the smallest number of frames that still sounds smooth.\n"); Chris@4: printf("Note that the sound will stop momentarily when you change the number of buffers.\n"); Chris@4: Chris@4: /* Get bufferSize from command line. */ Chris@4: framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE; Chris@4: printf("Frames per buffer = %d\n", framesPerBuffer ); Chris@4: Chris@4: data.left_phase = data.right_phase = 0.0; Chris@4: Chris@4: err = Pa_Initialize(); Chris@4: if( err != paNoError ) goto error; Chris@4: Chris@4: outLatency = sampleRate * 200.0 / 1000.0; /* 200 msec. */ Chris@4: Chris@4: /* Try different numBuffers in a loop. */ Chris@4: go = 1; Chris@4: while( go ) Chris@4: { Chris@4: outputParameters.device = Pa_GetDefaultOutputDevice(); /* Default output device. */ Chris@4: outputParameters.channelCount = 2; /* Stereo output */ Chris@4: outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */ Chris@4: outputParameters.suggestedLatency = (double)outLatency / sampleRate; /* In seconds. */ Chris@4: outputParameters.hostApiSpecificStreamInfo = NULL; Chris@4: Chris@4: printf("Latency = %d frames = %6.1f msec.\n", outLatency, outputParameters.suggestedLatency * 1000.0 ); Chris@4: Chris@4: err = Pa_OpenStream( Chris@4: &stream, Chris@4: NULL, /* no input */ Chris@4: &outputParameters, Chris@4: sampleRate, Chris@4: framesPerBuffer, Chris@4: paClipOff, /* we won't output out of range samples so don't bother clipping them */ Chris@4: paminlatCallback, Chris@4: &data ); Chris@4: if( err != paNoError ) goto error; Chris@4: if( stream == NULL ) goto error; Chris@4: Chris@4: /* Start audio. */ Chris@4: err = Pa_StartStream( stream ); Chris@4: if( err != paNoError ) goto error; Chris@4: Chris@4: /* Ask user for a new nlatency. */ Chris@4: printf("\nMove windows around to see if the sound glitches.\n"); Chris@4: printf("Latency now %d, enter new number of frames, or 'q' to quit: ", outLatency ); Chris@4: line = fgets( str, 256, stdin ); Chris@4: if( line == NULL ) Chris@4: { Chris@4: go = 0; Chris@4: } Chris@4: else Chris@4: { Chris@4: { Chris@4: /* Get rid of newline */ Chris@4: size_t l = strlen( str ) - 1; Chris@4: if( str[ l ] == '\n') Chris@4: str[ l ] = '\0'; Chris@4: } Chris@4: Chris@4: Chris@4: if( str[0] == 'q' ) go = 0; Chris@4: else Chris@4: { Chris@4: outLatency = atol( str ); Chris@4: if( outLatency < minLatency ) Chris@4: { Chris@4: printf( "Latency below minimum of %d! Set to minimum!!!\n", minLatency ); Chris@4: outLatency = minLatency; Chris@4: } Chris@4: } Chris@4: Chris@4: } Chris@4: /* Stop sound until ENTER hit. */ Chris@4: err = Pa_StopStream( stream ); Chris@4: if( err != paNoError ) goto error; Chris@4: err = Pa_CloseStream( stream ); Chris@4: if( err != paNoError ) goto error; Chris@4: } Chris@4: printf("A good setting for latency would be somewhat higher than\n"); Chris@4: printf("the minimum latency that worked.\n"); Chris@4: printf("PortAudio: Test finished.\n"); Chris@4: Pa_Terminate(); Chris@4: return 0; Chris@4: error: Chris@4: Pa_Terminate(); 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: return 1; Chris@4: }