cannam@89: /** @file pa_minlat.c cannam@89: @ingroup test_src cannam@89: @brief Experiment with different numbers of buffers to determine the cannam@89: minimum latency for a computer. cannam@89: @author Phil Burk http://www.softsynth.com cannam@89: */ cannam@89: /* cannam@89: * $Id: pa_minlat.c 1612 2011-02-28 23:56:48Z philburk $ 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 cannam@89: #include cannam@89: #include cannam@89: #include cannam@89: #include "portaudio.h" cannam@89: cannam@89: #ifndef M_PI cannam@89: #define M_PI (3.14159265) cannam@89: #endif cannam@89: #define TWOPI (M_PI * 2.0) cannam@89: cannam@89: #define DEFAULT_BUFFER_SIZE (32) cannam@89: cannam@89: typedef struct cannam@89: { cannam@89: double left_phase; cannam@89: double right_phase; cannam@89: } cannam@89: paTestData; cannam@89: cannam@89: /* Very simple synthesis routine to generate two sine waves. */ cannam@89: static int paminlatCallback( const void *inputBuffer, void *outputBuffer, cannam@89: unsigned long framesPerBuffer, cannam@89: const PaStreamCallbackTimeInfo* timeInfo, cannam@89: PaStreamCallbackFlags statusFlags, cannam@89: void *userData ) cannam@89: { cannam@89: paTestData *data = (paTestData*)userData; cannam@89: float *out = (float*)outputBuffer; cannam@89: unsigned int i; cannam@89: double left_phaseInc = 0.02; cannam@89: double right_phaseInc = 0.06; cannam@89: cannam@89: double left_phase = data->left_phase; cannam@89: double right_phase = data->right_phase; cannam@89: cannam@89: for( i=0; i TWOPI ) left_phase -= TWOPI; cannam@89: *out++ = (float) sin( left_phase ); cannam@89: cannam@89: right_phase += right_phaseInc; cannam@89: if( right_phase > TWOPI ) right_phase -= TWOPI; cannam@89: *out++ = (float) sin( right_phase ); cannam@89: } cannam@89: cannam@89: data->left_phase = left_phase; cannam@89: data->right_phase = right_phase; cannam@89: return 0; cannam@89: } cannam@89: cannam@89: int main( int argc, char **argv ); cannam@89: int main( int argc, char **argv ) cannam@89: { cannam@89: PaStreamParameters outputParameters; cannam@89: PaStream *stream; cannam@89: PaError err; cannam@89: paTestData data; cannam@89: int go; cannam@89: int outLatency = 0; cannam@89: int minLatency = DEFAULT_BUFFER_SIZE * 2; cannam@89: int framesPerBuffer; cannam@89: double sampleRate = 44100.0; cannam@89: char str[256]; cannam@89: char *line; cannam@89: cannam@89: printf("pa_minlat - Determine minimum latency for your computer.\n"); cannam@89: printf(" usage: pa_minlat {userBufferSize}\n"); cannam@89: printf(" for example: pa_minlat 64\n"); cannam@89: printf("Adjust your stereo until you hear a smooth tone in each speaker.\n"); cannam@89: printf("Then try to find the smallest number of frames that still sounds smooth.\n"); cannam@89: printf("Note that the sound will stop momentarily when you change the number of buffers.\n"); cannam@89: cannam@89: /* Get bufferSize from command line. */ cannam@89: framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE; cannam@89: printf("Frames per buffer = %d\n", framesPerBuffer ); cannam@89: cannam@89: data.left_phase = data.right_phase = 0.0; cannam@89: cannam@89: err = Pa_Initialize(); cannam@89: if( err != paNoError ) goto error; cannam@89: cannam@89: outLatency = sampleRate * 200.0 / 1000.0; /* 200 msec. */ cannam@89: cannam@89: /* Try different numBuffers in a loop. */ cannam@89: go = 1; cannam@89: while( go ) cannam@89: { cannam@89: outputParameters.device = Pa_GetDefaultOutputDevice(); /* Default output device. */ cannam@89: outputParameters.channelCount = 2; /* Stereo output */ cannam@89: outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */ cannam@89: outputParameters.suggestedLatency = (double)outLatency / sampleRate; /* In seconds. */ cannam@89: outputParameters.hostApiSpecificStreamInfo = NULL; cannam@89: cannam@89: printf("Latency = %d frames = %6.1f msec.\n", outLatency, outputParameters.suggestedLatency * 1000.0 ); cannam@89: cannam@89: err = Pa_OpenStream( cannam@89: &stream, cannam@89: NULL, /* no input */ cannam@89: &outputParameters, cannam@89: sampleRate, cannam@89: framesPerBuffer, cannam@89: paClipOff, /* we won't output out of range samples so don't bother clipping them */ cannam@89: paminlatCallback, cannam@89: &data ); cannam@89: if( err != paNoError ) goto error; cannam@89: if( stream == NULL ) goto error; cannam@89: cannam@89: /* Start audio. */ cannam@89: err = Pa_StartStream( stream ); cannam@89: if( err != paNoError ) goto error; cannam@89: cannam@89: /* Ask user for a new nlatency. */ cannam@89: printf("\nMove windows around to see if the sound glitches.\n"); cannam@89: printf("Latency now %d, enter new number of frames, or 'q' to quit: ", outLatency ); cannam@89: line = fgets( str, 256, stdin ); cannam@89: if( line == NULL ) cannam@89: { cannam@89: go = 0; cannam@89: } cannam@89: else cannam@89: { cannam@89: { cannam@89: /* Get rid of newline */ cannam@89: size_t l = strlen( str ) - 1; cannam@89: if( str[ l ] == '\n') cannam@89: str[ l ] = '\0'; cannam@89: } cannam@89: cannam@89: cannam@89: if( str[0] == 'q' ) go = 0; cannam@89: else cannam@89: { cannam@89: outLatency = atol( str ); cannam@89: if( outLatency < minLatency ) cannam@89: { cannam@89: printf( "Latency below minimum of %d! Set to minimum!!!\n", minLatency ); cannam@89: outLatency = minLatency; cannam@89: } cannam@89: } cannam@89: cannam@89: } cannam@89: /* Stop sound until ENTER hit. */ cannam@89: err = Pa_StopStream( stream ); cannam@89: if( err != paNoError ) goto error; cannam@89: err = Pa_CloseStream( stream ); cannam@89: if( err != paNoError ) goto error; cannam@89: } cannam@89: printf("A good setting for latency would be somewhat higher than\n"); cannam@89: printf("the minimum latency that worked.\n"); cannam@89: printf("PortAudio: Test finished.\n"); cannam@89: Pa_Terminate(); cannam@89: return 0; cannam@89: error: cannam@89: Pa_Terminate(); 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: return 1; cannam@89: }