diff options
Diffstat (limited to 'pd/portaudio_v18/pa_tests/pa_minlat.c')
| -rw-r--r-- | pd/portaudio_v18/pa_tests/pa_minlat.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/pd/portaudio_v18/pa_tests/pa_minlat.c b/pd/portaudio_v18/pa_tests/pa_minlat.c new file mode 100644 index 00000000..7256cc00 --- /dev/null +++ b/pd/portaudio_v18/pa_tests/pa_minlat.c @@ -0,0 +1,172 @@ +/* + * $Id: pa_minlat.c,v 1.4 2002/04/30 18:19:00 philburk Exp $ + * paminlat.c + * Experiment with different numbers of buffers to determine the + * minimum latency for a computer. + * + * Author: Phil Burk http://www.softsynth.com + * + * This program uses the PortAudio Portable Audio Library. + * For more information see: http://www.portaudio.com + * Copyright (c) 1999-2000 Ross Bencina and Phil Burk + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files + * (the "Software"), to deal in the Software without restriction, + * including without limitation the rights to use, copy, modify, merge, + * publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, + * subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * Any person wishing to distribute modifications to the Software is + * requested to send the modifications to the original developer so that + * they can be incorporated into the canonical version. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + */ +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include "portaudio.h" + +#ifndef M_PI +#define M_PI (3.14159265) +#endif +#define TWOPI (M_PI * 2.0) + +#define DEFAULT_BUFFER_SIZE (64) + +typedef struct +{ + double left_phase; + double right_phase; +} +paTestData; + +/* Very simple synthesis routine to generate two sine waves. */ +static int paminlatCallback( void *inputBuffer, void *outputBuffer, + unsigned long framesPerBuffer, + PaTimestamp outTime, void *userData ) +{ + paTestData *data = (paTestData*)userData; + float *out = (float*)outputBuffer; + unsigned int i; + double left_phaseInc = 0.02; + double right_phaseInc = 0.06; + + double left_phase = data->left_phase; + double right_phase = data->right_phase; + + for( i=0; i<framesPerBuffer; i++ ) + { + left_phase += left_phaseInc; + if( left_phase > TWOPI ) left_phase -= TWOPI; + *out++ = (float) sin( left_phase ); + + right_phase += right_phaseInc; + if( right_phase > TWOPI ) right_phase -= TWOPI; + *out++ = (float) sin( right_phase ); + } + + data->left_phase = left_phase; + data->right_phase = right_phase; + return 0; +} +void main( int argc, char **argv ); +void main( int argc, char **argv ) +{ + PortAudioStream *stream; + PaError err; + paTestData data; + int go; + int numBuffers = 0; + int minBuffers = 0; + int framesPerBuffer; + double sampleRate = 44100.0; + char str[256]; + printf("paminlat - Determine minimum latency for your computer.\n"); + printf(" usage: paminlat {framesPerBuffer}\n"); + printf(" for example: paminlat 256\n"); + printf("Adjust your stereo until you hear a smooth tone in each speaker.\n"); + printf("Then try to find the smallest number of buffers that still sounds smooth.\n"); + printf("Note that the sound will stop momentarily when you change the number of buffers.\n"); + /* Get bufferSize from command line. */ + framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE; + printf("Frames per buffer = %d\n", framesPerBuffer ); + + data.left_phase = data.right_phase = 0.0; + err = Pa_Initialize(); + if( err != paNoError ) goto error; + /* Ask PortAudio for the recommended minimum number of buffers. */ + numBuffers = minBuffers = Pa_GetMinNumBuffers( framesPerBuffer, sampleRate ); + printf("NumBuffers set to %d based on a call to Pa_GetMinNumBuffers()\n", numBuffers ); + /* Try different numBuffers in a loop. */ + go = 1; + while( go ) + { + + printf("Latency = framesPerBuffer * numBuffers = %d * %d = %d frames = %d msecs.\n", + framesPerBuffer, numBuffers, framesPerBuffer*numBuffers, + (int)((1000 * framesPerBuffer * numBuffers) / sampleRate) ); + err = Pa_OpenStream( + &stream, + paNoDevice, + 0, /* no input */ + paFloat32, /* 32 bit floating point input */ + NULL, + Pa_GetDefaultOutputDeviceID(), /* default output device */ + 2, /* stereo output */ + paFloat32, /* 32 bit floating point output */ + NULL, + sampleRate, + framesPerBuffer, + numBuffers, /* number of buffers */ + paClipOff, /* we won't output out of range samples so don't bother clipping them */ + paminlatCallback, + &data ); + if( err != paNoError ) goto error; + if( stream == NULL ) goto error; + /* Start audio. */ + err = Pa_StartStream( stream ); + if( err != paNoError ) goto error; + /* Ask user for a new number of buffers. */ + printf("\nMove windows around to see if the sound glitches.\n"); + printf("NumBuffers currently %d, enter new number, or 'q' to quit: ", numBuffers ); + gets( str ); + if( str[0] == 'q' ) go = 0; + else + { + numBuffers = atol( str ); + if( numBuffers < minBuffers ) + { + printf( "numBuffers below minimum of %d! Set to minimum!!!\n", minBuffers ); + numBuffers = minBuffers; + } + } + /* Stop sound until ENTER hit. */ + err = Pa_StopStream( stream ); + if( err != paNoError ) goto error; + err = Pa_CloseStream( stream ); + if( err != paNoError ) goto error; + } + printf("A good setting for latency would be somewhat higher than\n"); + printf("the minimum latency that worked.\n"); + printf("PortAudio: Test finished.\n"); + Pa_Terminate(); + return; +error: + Pa_Terminate(); + fprintf( stderr, "An error occured while using the portaudio stream\n" ); + fprintf( stderr, "Error number: %d\n", err ); + fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) ); +} |