/* * $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 #include #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; istate ) { 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 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; }