patest_sync.c File Reference

Test time stamping and synchronization of audio and video. More...

#include <stdio.h>
#include <math.h>
#include "portaudio.h"
#include "pa_util.h"

Data Structures
struct	paTestData

Macros
#define	NUM_BEEPS   (6)
#define	SAMPLE_RATE   (44100)
#define	SAMPLE_PERIOD   (1.0/44100.0)
#define	FRAMES_PER_BUFFER   (256)
#define	BEEP_DURATION   (400)
#define	LATENCY_MSEC   (2000)
#define	SLEEP_MSEC   (10)
#define	TIMEOUT_MSEC   (15000)
#define	STATE_BKG_IDLE   (0)
#define	STATE_BKG_PENDING   (1)
#define	STATE_BKG_BEEPING   (2)

Functions
int	main (void)

Detailed Description

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:

1. Foreground requests a beep.
2. Background randomly schedules a beep.
3. Foreground waits for the beep to be heard based on PaUtil_GetTime().
4. Foreground outputs video (printf) in sync with audio.
5. Repeat.

Author

Phil Burk http://www.softsynth.com

Macro Definition Documentation

BEEP_DURATION

#define BEEP_DURATION   (400)

FRAMES_PER_BUFFER

#define FRAMES_PER_BUFFER   (256)

Referenced by main().

LATENCY_MSEC

#define LATENCY_MSEC   (2000)

Referenced by main().

NUM_BEEPS

#define NUM_BEEPS   (6)

Referenced by main().

SAMPLE_PERIOD

#define SAMPLE_PERIOD   (1.0/44100.0)

SAMPLE_RATE

#define SAMPLE_RATE   (44100)

Referenced by main().

SLEEP_MSEC

#define SLEEP_MSEC   (10)

Referenced by main().

STATE_BKG_BEEPING

#define STATE_BKG_BEEPING   (2)

STATE_BKG_IDLE

#define STATE_BKG_IDLE   (0)

Referenced by main().

STATE_BKG_PENDING

#define STATE_BKG_PENDING   (1)

TIMEOUT_MSEC

#define TIMEOUT_MSEC   (15000)

Referenced by main().

Function Documentation

main()

int main

(

void

)

References paTestData::beepTime, PaStreamParameters::channelCount, PaStreamParameters::device, FRAMES_PER_BUFFER, PaStreamParameters::hostApiSpecificStreamInfo, paTestData::latency, LATENCY_MSEC, paTestData::left_phase, NUM_BEEPS, Pa_CloseStream(), Pa_GetDefaultOutputDevice(), Pa_GetErrorText(), Pa_GetStreamTime(), Pa_Initialize(), Pa_OpenStream(), Pa_Sleep(), Pa_StartStream(), Pa_StopStream(), Pa_Terminate(), paClipOff, paFloat32, paNoDevice, paNoError, PaUtil_GetTime(), paTestData::requestBeep, paTestData::right_phase, SAMPLE_RATE, PaStreamParameters::sampleFormat, SLEEP_MSEC, paTestData::state, STATE_BKG_IDLE, PaStreamParameters::suggestedLatency, and TIMEOUT_MSEC.