patest_mono.c

mediastreamer2是开源的网络传输媒体流的库

/*
 * $Id: patest_mono.c 848 2004-12-14 10:23:57Z rossbencina $
 * patest_sine.c
 * Play a monophonic sine wave using the Portable Audio api for several seconds.
 *
 * Authors:
 *    Ross Bencina <[e-mail]>
 *    Phil Burk <[e-mail]>
 *
 * This program uses the PortAudio Portable Audio Library.
 * For more information see: http://www.audiomulch.com/portaudio/
 * 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_SECONDS   (10)
#define SAMPLE_RATE   (44100)
#define AMPLITUDE     (0.8)
#define FRAMES_PER_BUFFER  (64)
#define OUTPUT_DEVICE Pa_GetDefaultOutputDevice()

#ifndef M_PI
#define M_PI  (3.14159265)
#endif

#define TABLE_SIZE   (200)
typedef struct
{
    float sine[TABLE_SIZE];
    int phase;
}
paTestData;

/* 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( const void *inputBuffer, void *outputBuffer,
                            unsigned long framesPerBuffer,
                            const PaStreamCallbackTimeInfo* timeInfo,
                            PaStreamCallbackFlags statusFlags,
                            void *userData )
{
    paTestData *data = (paTestData*)userData;
    float *out = (float*)outputBuffer;
    unsigned long i;
    int finished = 0;
    /* avoid unused variable warnings */
    (void) inputBuffer;
    (void) timeInfo;
    (void) statusFlags;
    for( i=0; i<framesPerBuffer; i++ )
    {
        *out++ = data->sine[data->phase];  /* left */
        data->phase += 1;
        if( data->phase >= TABLE_SIZE ) data->phase -= TABLE_SIZE;
    }
    return finished;
}

/*******************************************************************/
int main(void);
int main(void)
{
    PaStreamParameters outputParameters;
    PaStream *stream;
    PaError err;
    paTestData data;
    int i;
    printf("PortAudio Test: output MONO sine wave. SR = %d, BufSize = %d\n", SAMPLE_RATE, FRAMES_PER_BUFFER);
    /* initialise sinusoidal wavetable */
    for( i=0; i<TABLE_SIZE; i++ )
    {
        data.sine[i] = (float) (AMPLITUDE * sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. ));
    }
    data.phase = 0;
    
    err = Pa_Initialize();
    if( err != paNoError ) goto error;

    outputParameters.device = OUTPUT_DEVICE;
    outputParameters.channelCount = 1;       /* MONO output */
    outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output */
    outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency;
    outputParameters.hostApiSpecificStreamInfo = NULL;

    err = Pa_OpenStream(
              &stream,
              NULL, /* no input */
              &outputParameters,
              SAMPLE_RATE,
              FRAMES_PER_BUFFER,
              paClipOff,      /* we won't output out of range samples so don't bother clipping them */
              patestCallback,
              &data );
    if( err != paNoError ) goto error;

    err = Pa_StartStream( stream );
    if( err != paNoError ) goto error;
    
    printf("Play for %d seconds.\n", NUM_SECONDS ); fflush(stdout);
    Pa_Sleep( NUM_SECONDS * 1000 );

    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;
}