microphonedevicedriver.cpp

来自「一个语言识别引擎」· C++ 代码 · 共 103 行

// -*- mode:C++; tab-width:4; c-basic-offset:4; indent-tabs-mode:nil -*-

/*
 * Copyright (C) 2006 Paul Fitzpatrick
 * CopyPolicy: Released under the terms of the GNU GPL v2.0.
 *
 */

#include <yarp/MicrophoneDeviceDriver.h>

#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>	

#define SAMPLE_RATE	48000
#define NUM_SECONDS	0.1
#define	NUM_SAMPLES	((int)(SAMPLE_RATE*NUM_SECONDS))

char 		devname[] = "/dev/dsp";
unsigned char	pulsecode[ NUM_SAMPLES ];

using namespace yarp::os;
using namespace yarp::dev;


MicrophoneDeviceDriver::MicrophoneDeviceDriver() {
    dsp = -1;
}

MicrophoneDeviceDriver::~MicrophoneDeviceDriver() {
    close();
}

bool MicrophoneDeviceDriver::open(yarp::os::Searchable& config) {

    printf("WARNING: the MicrophoneDeviceDriver is just a cartoon\n");
    printf("WARNING: it hasn't really been written yet\n");

	short	nChannels = 1;
	int	samplesPerSec = SAMPLE_RATE;
	short	bitsPerSample = 8;

	// open the audio device-file and set its capture parameters 
	int	bits = ( bitsPerSample == 8 ) ? AFMT_U8 : AFMT_S16_BE;
	int	chns = ( nChannels == 1 ) ? 1 : 2;
	int	rate = samplesPerSec;
	dsp = ::open( devname, O_RDONLY );
	if ( dsp < 0 ) { perror( devname ); exit(1); }
	if ( ioctl( dsp, SNDCTL_DSP_RESET, NULL ) < 0 )
		{ perror( "ioctl" ); exit(1); }
	if (	  ( ioctl( dsp, SNDCTL_DSP_SETFMT,   &bits ) < 0 )
              ||( ioctl( dsp, SNDCTL_DSP_CHANNELS, &chns ) < 0 )
              ||( ioctl( dsp, SNDCTL_DSP_SPEED,    &rate ) < 0 )	)
		{ perror( "audio format not not supported\n" ); exit(1); }

    printf("Ok, opened microphone...\n");
    
    return true;
}

bool MicrophoneDeviceDriver::close(void) {
    if (dsp!=-1) {
        ::close( dsp );
        dsp = -1;
    }
    return true;
}

bool MicrophoneDeviceDriver::getSound(yarp::sig::Sound& sound) {
	// main loop to capture the waveform audio data	
	unsigned char	*data = pulsecode;
	int	begun = 1;
	int	bytes_to_grab = NUM_SAMPLES / 16;
	int	bytes_to_save = NUM_SAMPLES;
	while ( bytes_to_save > 0 )
		{
            int	nbytes = read( dsp, data, bytes_to_grab );
            if ( !begun )
                {
                    int	max = 0;
                    for (int i = 0; i < nbytes; i++) 
                        if ( data[i] > max ) max = data[i];
                    if ( max > 0x99 ) begun = 1;
                    else	continue;
                }
            bytes_to_save -= nbytes;
            data += nbytes;
		}
    sound.resize(NUM_SAMPLES);
    double total = 0;
    for (int i=0; i<NUM_SAMPLES; i++) {
        sound.set(pulsecode[i],i);
        total += abs(pulsecode[i]-128);
    }
	printf( "grabbing a chunk of %d samples... magnitude: %g\n", 
            NUM_SAMPLES, total);
    return true;
}