cannam@140: /** @file pa_minlat.c cannam@140: @ingroup test_src cannam@140: @brief Experiment with different numbers of buffers to determine the cannam@140: minimum latency for a computer. cannam@140: @author Phil Burk http://www.softsynth.com cannam@140: */ cannam@140: /* cannam@140: * $Id$ cannam@140: * cannam@140: * This program uses the PortAudio Portable Audio Library. cannam@140: * For more information see: http://www.portaudio.com cannam@140: * Copyright (c) 1999-2000 Ross Bencina and Phil Burk cannam@140: * cannam@140: * Permission is hereby granted, free of charge, to any person obtaining cannam@140: * a copy of this software and associated documentation files cannam@140: * (the "Software"), to deal in the Software without restriction, cannam@140: * including without limitation the rights to use, copy, modify, merge, cannam@140: * publish, distribute, sublicense, and/or sell copies of the Software, cannam@140: * and to permit persons to whom the Software is furnished to do so, cannam@140: * subject to the following conditions: cannam@140: * cannam@140: * The above copyright notice and this permission notice shall be cannam@140: * included in all copies or substantial portions of the Software. cannam@140: * cannam@140: * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, cannam@140: * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF cannam@140: * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. cannam@140: * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR cannam@140: * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF cannam@140: * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION cannam@140: * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. cannam@140: */ cannam@140: cannam@140: /* cannam@140: * The text above constitutes the entire PortAudio license; however, cannam@140: * the PortAudio community also makes the following non-binding requests: cannam@140: * cannam@140: * Any person wishing to distribute modifications to the Software is cannam@140: * requested to send the modifications to the original developer so that cannam@140: * they can be incorporated into the canonical version. It is also cannam@140: * requested that these non-binding requests be included along with the cannam@140: * license above. cannam@140: */ cannam@140: cannam@140: #include cannam@140: #include cannam@140: #include cannam@140: #include cannam@140: #include "portaudio.h" cannam@140: cannam@140: #ifndef M_PI cannam@140: #define M_PI (3.14159265) cannam@140: #endif cannam@140: #define TWOPI (M_PI * 2.0) cannam@140: cannam@140: #define DEFAULT_BUFFER_SIZE (32) cannam@140: cannam@140: typedef struct cannam@140: { cannam@140: double left_phase; cannam@140: double right_phase; cannam@140: } cannam@140: paTestData; cannam@140: cannam@140: /* Very simple synthesis routine to generate two sine waves. */ cannam@140: static int paminlatCallback( const void *inputBuffer, void *outputBuffer, cannam@140: unsigned long framesPerBuffer, cannam@140: const PaStreamCallbackTimeInfo* timeInfo, cannam@140: PaStreamCallbackFlags statusFlags, cannam@140: void *userData ) cannam@140: { cannam@140: paTestData *data = (paTestData*)userData; cannam@140: float *out = (float*)outputBuffer; cannam@140: unsigned int i; cannam@140: double left_phaseInc = 0.02; cannam@140: double right_phaseInc = 0.06; cannam@140: cannam@140: double left_phase = data->left_phase; cannam@140: double right_phase = data->right_phase; cannam@140: cannam@140: for( i=0; i TWOPI ) left_phase -= TWOPI; cannam@140: *out++ = (float) sin( left_phase ); cannam@140: cannam@140: right_phase += right_phaseInc; cannam@140: if( right_phase > TWOPI ) right_phase -= TWOPI; cannam@140: *out++ = (float) sin( right_phase ); cannam@140: } cannam@140: cannam@140: data->left_phase = left_phase; cannam@140: data->right_phase = right_phase; cannam@140: return 0; cannam@140: } cannam@140: cannam@140: int main( int argc, char **argv ); cannam@140: int main( int argc, char **argv ) cannam@140: { cannam@140: PaStreamParameters outputParameters; cannam@140: PaStream *stream; cannam@140: PaError err; cannam@140: paTestData data; cannam@140: int go; cannam@140: int outLatency = 0; cannam@140: int minLatency = DEFAULT_BUFFER_SIZE * 2; cannam@140: int framesPerBuffer; cannam@140: double sampleRate = 44100.0; cannam@140: char str[256]; cannam@140: char *line; cannam@140: cannam@140: printf("pa_minlat - Determine minimum latency for your computer.\n"); cannam@140: printf(" usage: pa_minlat {userBufferSize}\n"); cannam@140: printf(" for example: pa_minlat 64\n"); cannam@140: printf("Adjust your stereo until you hear a smooth tone in each speaker.\n"); cannam@140: printf("Then try to find the smallest number of frames that still sounds smooth.\n"); cannam@140: printf("Note that the sound will stop momentarily when you change the number of buffers.\n"); cannam@140: cannam@140: /* Get bufferSize from command line. */ cannam@140: framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE; cannam@140: printf("Frames per buffer = %d\n", framesPerBuffer ); cannam@140: cannam@140: data.left_phase = data.right_phase = 0.0; cannam@140: cannam@140: err = Pa_Initialize(); cannam@140: if( err != paNoError ) goto error; cannam@140: cannam@140: outLatency = sampleRate * 200.0 / 1000.0; /* 200 msec. */ cannam@140: cannam@140: /* Try different numBuffers in a loop. */ cannam@140: go = 1; cannam@140: while( go ) cannam@140: { cannam@140: outputParameters.device = Pa_GetDefaultOutputDevice(); /* Default output device. */ cannam@140: outputParameters.channelCount = 2; /* Stereo output */ cannam@140: outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */ cannam@140: outputParameters.suggestedLatency = (double)outLatency / sampleRate; /* In seconds. */ cannam@140: outputParameters.hostApiSpecificStreamInfo = NULL; cannam@140: cannam@140: printf("Latency = %d frames = %6.1f msec.\n", outLatency, outputParameters.suggestedLatency * 1000.0 ); cannam@140: cannam@140: err = Pa_OpenStream( cannam@140: &stream, cannam@140: NULL, /* no input */ cannam@140: &outputParameters, cannam@140: sampleRate, cannam@140: framesPerBuffer, cannam@140: paClipOff, /* we won't output out of range samples so don't bother clipping them */ cannam@140: paminlatCallback, cannam@140: &data ); cannam@140: if( err != paNoError ) goto error; cannam@140: if( stream == NULL ) goto error; cannam@140: cannam@140: /* Start audio. */ cannam@140: err = Pa_StartStream( stream ); cannam@140: if( err != paNoError ) goto error; cannam@140: cannam@140: /* Ask user for a new nlatency. */ cannam@140: printf("\nMove windows around to see if the sound glitches.\n"); cannam@140: printf("Latency now %d, enter new number of frames, or 'q' to quit: ", outLatency ); cannam@140: line = fgets( str, 256, stdin ); cannam@140: if( line == NULL ) cannam@140: { cannam@140: go = 0; cannam@140: } cannam@140: else cannam@140: { cannam@140: { cannam@140: /* Get rid of newline */ cannam@140: size_t l = strlen( str ) - 1; cannam@140: if( str[ l ] == '\n') cannam@140: str[ l ] = '\0'; cannam@140: } cannam@140: cannam@140: cannam@140: if( str[0] == 'q' ) go = 0; cannam@140: else cannam@140: { cannam@140: outLatency = atol( str ); cannam@140: if( outLatency < minLatency ) cannam@140: { cannam@140: printf( "Latency below minimum of %d! Set to minimum!!!\n", minLatency ); cannam@140: outLatency = minLatency; cannam@140: } cannam@140: } cannam@140: cannam@140: } cannam@140: /* Stop sound until ENTER hit. */ cannam@140: err = Pa_StopStream( stream ); cannam@140: if( err != paNoError ) goto error; cannam@140: err = Pa_CloseStream( stream ); cannam@140: if( err != paNoError ) goto error; cannam@140: } cannam@140: printf("A good setting for latency would be somewhat higher than\n"); cannam@140: printf("the minimum latency that worked.\n"); cannam@140: printf("PortAudio: Test finished.\n"); cannam@140: Pa_Terminate(); cannam@140: return 0; cannam@140: error: cannam@140: Pa_Terminate(); cannam@140: fprintf( stderr, "An error occured while using the portaudio stream\n" ); cannam@140: fprintf( stderr, "Error number: %d\n", err ); cannam@140: fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) ); cannam@140: return 1; cannam@140: }