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Change sine generation method so that sine waves don't line up with PA buffers.

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This was causing it to appear that audio was OK even when buffers were dropped..
This commit is contained in:
philburk 2002-04-19 18:31:13 +00:00
commit baefbbdc4a
1 changed files with 24 additions and 16 deletions
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40
pa_tests/pa_minlat.c
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@ -38,18 +38,21 @@
#include <stdlib.h> #include <stdlib.h>
#include <math.h> #include <math.h>
#include "portaudio.h" #include "portaudio.h"
#ifndef M_PI #ifndef M_PI
#define M_PI (3.14159265) #define M_PI (3.14159265)
#endif #endif
#define TWOPI (M_PI * 2.0)
#define DEFAULT_BUFFER_SIZE (64) #define DEFAULT_BUFFER_SIZE (64)
#define TABLE_SIZE (200) #define TABLE_SIZE (200)
typedef struct typedef struct
{ {
float sine[TABLE_SIZE]; double left_phase;
int left_phase; double right_phase;
int right_phase;
} }
paTestData; paTestData;
/* Very simple synthesis routine to generate two sine waves. */ /* Very simple synthesis routine to generate two sine waves. */
static int paminlatCallback( void *inputBuffer, void *outputBuffer, static int paminlatCallback( void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer, unsigned long framesPerBuffer,
@ -58,15 +61,25 @@ static int paminlatCallback( void *inputBuffer, void *outputBuffer,
paTestData *data = (paTestData*)userData; paTestData *data = (paTestData*)userData;
float *out = (float*)outputBuffer; float *out = (float*)outputBuffer;
unsigned int i; 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++ ) for( i=0; i<framesPerBuffer; i++ )
{ {
*out++ = data->sine[data->left_phase]; /* left */ left_phase += left_phaseInc;
*out++ = data->sine[data->right_phase]; /* right */ if( left_phase > TWOPI ) left_phase -= TWOPI;
data->left_phase += 1; *out++ = (float) sin( left_phase );
if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
data->right_phase += 3; /* higher pitch so we can distinguish left and right. */ right_phase += right_phaseInc;
if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE; if( right_phase > TWOPI ) right_phase -= TWOPI;
*out++ = (float) sin( right_phase );
} }
data->left_phase = left_phase;
data->right_phase = right_phase;
return 0; return 0;
} }
void main( int argc, char **argv ); void main( int argc, char **argv );
@ -75,7 +88,6 @@ void main( int argc, char **argv )
PortAudioStream *stream; PortAudioStream *stream;
PaError err; PaError err;
paTestData data; paTestData data;
int i;
int go; int go;
int numBuffers = 0; int numBuffers = 0;
int minBuffers = 0; int minBuffers = 0;
@ -91,12 +103,8 @@ void main( int argc, char **argv )
/* Get bufferSize from command line. */ /* Get bufferSize from command line. */
framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE; framesPerBuffer = ( argc > 1 ) ? atol( argv[1] ) : DEFAULT_BUFFER_SIZE;
printf("Frames per buffer = %d\n", framesPerBuffer ); printf("Frames per buffer = %d\n", framesPerBuffer );
/* Initialise sinusoidal wavetable. */
for( i=0; i<TABLE_SIZE; i++ ) data.left_phase = data.right_phase = 0.0;
{
data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
}
data.left_phase = data.right_phase = 0;
err = Pa_Initialize(); err = Pa_Initialize();
if( err != paNoError ) goto error; if( err != paNoError ) goto error;
/* Ask PortAudio for the recommended minimum number of buffers. */ /* Ask PortAudio for the recommended minimum number of buffers. */