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/*
* $Id: patest_sync.c,v 1.1.1.1 2002/01/22 00:52:40 phil Exp $
* patest_sync.c
* Test time stamping and synchronization of audio and video.
* A high latency is used so we can hear the difference in time.
* Random durations are used so we know we are hearing the right beep
* and not the one before or after.
*
* Sequence of events:
* Foreground requests a beep.
* Background randomly schedules a beep.
* Foreground waits for the beep to be heard based on Pa_StreamTime().
* Foreground outputs video (printf) in sync with audio.
* Repeat.
*
* 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 <math.h>
#include "portaudio.h"
#define NUM_BEEPS (6)
#define SAMPLE_RATE (44100)
#define FRAMES_PER_BUFFER (256)
#define BEEP_DURATION (1000)
#define LATENCY_MSEC (2000)
#define SLEEP_MSEC (10)
#define TIMEOUT_MSEC ((3 * LATENCY_MSEC) / (2 * SLEEP_MSEC))
#define NUM_BUFFERS ((LATENCY_MSEC * SAMPLE_RATE) / (FRAMES_PER_BUFFER * 1000))
#define STATE_BKG_IDLE (0)
#define STATE_BKG_PENDING (1)
#define STATE_BKG_BEEPING (2)
typedef struct
{
float left_phase;
float right_phase;
int state;
int requestBeep; /* Set by foreground, cleared by background. */
PaTimestamp beepTime;
int beepCount;
}
paTestData;
static unsigned long GenerateRandomNumber( void );
/************************************************************/
/* Calculate pseudo-random 32 bit number based on linear congruential method. */
static unsigned long GenerateRandomNumber( void )
{
static unsigned long randSeed = 22222; /* Change this for different random sequences. */
randSeed = (randSeed * 196314165) + 907633515;
return randSeed;
}
/* This routine will be called by the PortAudio engine when audio is needed.
** It may called at interrupt level on some machines so don't do anything
** that could mess up the system like calling malloc() or free().
*/
static int patestCallback( void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer,
PaTimestamp outTime, void *userData )
{
/* Cast data passed through stream to our structure. */
paTestData *data = (paTestData*)userData;
float *out = (float*)outputBuffer;
unsigned int i;
(void) inputBuffer;
for( i=0; i<framesPerBuffer; i++ )
{
switch( data->state )
{
case STATE_BKG_IDLE:
/* Schedule beep at some random time in the future. */
if( data->requestBeep )
{
int random = GenerateRandomNumber() >> 14;
data->beepTime = outTime + (i + random + (SAMPLE_RATE/4));
data->state = STATE_BKG_PENDING;
data->requestBeep = 0;
data->left_phase = data->right_phase = 0.0;
}
*out++ = 0.0; /* left */
*out++ = 0.0; /* right */
break;
case STATE_BKG_PENDING:
if( (outTime + i) >= data->beepTime )
{
data->state = STATE_BKG_BEEPING;
data->beepCount = BEEP_DURATION;
}
*out++ = 0.0; /* left */
*out++ = 0.0; /* right */
break;
case STATE_BKG_BEEPING:
if( data->beepCount <= 0 )
{
data->state = STATE_BKG_IDLE;
*out++ = 0.0; /* left */
*out++ = 0.0; /* right */
}
else
{
/* Play sawtooth wave. */
*out++ = data->left_phase; /* left */
*out++ = data->right_phase; /* right */
/* Generate simple sawtooth phaser that ranges between -1.0 and 1.0. */
data->left_phase += 0.01f;
/* When signal reaches top, drop back down. */
if( data->left_phase >= 1.0f ) data->left_phase -= 2.0f;
/* higher pitch so we can distinguish left and right. */
data->right_phase += 0.03f;
if( data->right_phase >= 1.0f ) data->right_phase -= 2.0f;
}
data->beepCount -= 1;
break;
default:
data->state = STATE_BKG_IDLE;
break;
}
}
return 0;
}
/*******************************************************************/
int main(void);
int main(void)
{
PortAudioStream *stream;
PaError err;
paTestData DATA;
int i, timeout;
PaTimestamp previousTime;
printf("PortAudio Test: you should see BEEP at the same time you hear it.\n");
printf("Wait for a few seconds random delay between BEEPs.\n");
printf("BEEP %d times.\n", NUM_BEEPS );
/* Initialize our DATA for use by callback. */
DATA.left_phase = DATA.right_phase = 0.0;
DATA.state = STATE_BKG_IDLE;
DATA.requestBeep = 0;
/* Initialize library before making any other calls. */
err = Pa_Initialize();
if( err != paNoError ) goto error;
/* Open an audio I/O stream. */
err = Pa_OpenDefaultStream(
&stream,
0, /* no input channels */
2, /* stereo output */
paFloat32, /* 32 bit floating point output */
SAMPLE_RATE,
FRAMES_PER_BUFFER,
NUM_BUFFERS,
patestCallback,
&DATA );
if( err != paNoError ) goto error;
err = Pa_StartStream( stream );
if( err != paNoError ) goto error;
previousTime = Pa_StreamTime( stream );
for( i=0; i<NUM_BEEPS; i++ )
{
/* Request a beep from background. */
DATA.requestBeep = 1;
/* Wait for background to acknowledge request. */
timeout = TIMEOUT_MSEC;
while( (DATA.requestBeep == 1) && (timeout-- > 0 ) ) Pa_Sleep(SLEEP_MSEC);
if( timeout <= 0 )
{
fprintf( stderr, "Timed out waiting for background to acknowledge request.\n" );
goto error;
}
/* Wait for scheduled beep time. */
timeout = TIMEOUT_MSEC + (10000/SLEEP_MSEC);
while( (Pa_StreamTime( stream ) < DATA.beepTime) && (timeout-- > 0 ) )
{
Pa_Sleep(SLEEP_MSEC);
}
if( timeout <= 0 )
{
fprintf( stderr, "Timed out waiting for time. Now = %g, Beep for %g.\n",
Pa_StreamTime( stream ), DATA.beepTime );
goto error;
}
/* Beep should be sounding now so print synchronized BEEP. */
printf("BEEP");
fflush(stdout);
printf(" at %d, delta = %d\n",
(long) DATA.beepTime, (long) (DATA.beepTime - previousTime) );
fflush(stdout);
previousTime = DATA.beepTime;
}
err = Pa_StopStream( stream );
if( err != paNoError ) goto error;
err = Pa_CloseStream( stream );
if( err != paNoError ) goto error;
Pa_Terminate();
printf("Test finished.\n");
return err;
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 ) );
return err;
}
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