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authorsanine <sanine.not@pm.me>2022-08-25 14:54:53 -0500
committersanine <sanine.not@pm.me>2022-08-25 14:54:53 -0500
commit37c97e345d12f95dde44e1d1a4c2f2aadd4615bc (patch)
treee1bb25bc855883062bdd7847ff2c04290f71c840 /portaudio/test/pa_minlat.c
parent5634c7b04da619669f2f29f6798c03982be05180 (diff)
add initial structure
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+/** @file pa_minlat.c
+ @ingroup test_src
+ @brief Experiment with different numbers of buffers to determine the
+ minimum latency for a computer.
+ @author Phil Burk http://www.softsynth.com
+*/
+/*
+ * $Id$
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+/*
+ * The text above constitutes the entire PortAudio license; however,
+ * the PortAudio community also makes the following non-binding requests:
+ *
+ * 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. It is also
+ * requested that these non-binding requests be included along with the
+ * license above.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+#include "portaudio.h"
+
+#ifndef M_PI
+#define M_PI (3.14159265)
+#endif
+#define TWOPI (M_PI * 2.0)
+
+#define DEFAULT_BUFFER_SIZE (32)
+
+typedef struct
+{
+ double left_phase;
+ double right_phase;
+}
+paTestData;
+
+/* Very simple synthesis routine to generate two sine waves. */
+static int paminlatCallback( const void *inputBuffer, void *outputBuffer,
+ unsigned long framesPerBuffer,
+ const PaStreamCallbackTimeInfo* timeInfo,
+ PaStreamCallbackFlags statusFlags,
+ 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;
+}
+
+int main( int argc, char **argv );
+int main( int argc, char **argv )
+{
+ PaStreamParameters outputParameters;
+ PaStream *stream;
+ PaError err;
+ paTestData data;
+ int go;
+ int outLatency = 0;
+ int minLatency = DEFAULT_BUFFER_SIZE * 2;
+ int framesPerBuffer;
+ double sampleRate = 44100.0;
+ char str[256];
+ char *line;
+
+ printf("pa_minlat - Determine minimum latency for your computer.\n");
+ printf(" usage: pa_minlat {userBufferSize}\n");
+ printf(" for example: pa_minlat 64\n");
+ printf("Adjust your stereo until you hear a smooth tone in each speaker.\n");
+ printf("Then try to find the smallest number of frames 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;
+
+ outLatency = sampleRate * 200.0 / 1000.0; /* 200 msec. */
+
+ /* Try different numBuffers in a loop. */
+ go = 1;
+ while( go )
+ {
+ outputParameters.device = Pa_GetDefaultOutputDevice(); /* Default output device. */
+ outputParameters.channelCount = 2; /* Stereo output */
+ outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */
+ outputParameters.suggestedLatency = (double)outLatency / sampleRate; /* In seconds. */
+ outputParameters.hostApiSpecificStreamInfo = NULL;
+
+ printf("Latency = %d frames = %6.1f msec.\n", outLatency, outputParameters.suggestedLatency * 1000.0 );
+
+ err = Pa_OpenStream(
+ &stream,
+ NULL, /* no input */
+ &outputParameters,
+ sampleRate,
+ framesPerBuffer,
+ 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 nlatency. */
+ printf("\nMove windows around to see if the sound glitches.\n");
+ printf("Latency now %d, enter new number of frames, or 'q' to quit: ", outLatency );
+ line = fgets( str, 256, stdin );
+ if( line == NULL )
+ {
+ go = 0;
+ }
+ else
+ {
+ {
+ /* Get rid of newline */
+ size_t l = strlen( str ) - 1;
+ if( str[ l ] == '\n')
+ str[ l ] = '\0';
+ }
+
+
+ if( str[0] == 'q' ) go = 0;
+ else
+ {
+ outLatency = atol( str );
+ if( outLatency < minLatency )
+ {
+ printf( "Latency below minimum of %d! Set to minimum!!!\n", minLatency );
+ outLatency = minLatency;
+ }
+ }
+
+ }
+ /* 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 0;
+error:
+ Pa_Terminate();
+ fprintf( stderr, "An error occurred while using the portaudio stream\n" );
+ fprintf( stderr, "Error number: %d\n", err );
+ fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
+ return 1;
+}