ath.c

音频编码

}


double ATH ( double freq )
{
    static float tab [] = {
        /*    10.0 */  96.69, 96.69, 96.26, 95.12,
        /*    12.6 */  93.53, 91.13, 88.82, 86.76,
        /*    15.8 */  84.69, 82.43, 79.97, 77.48,
        /*    20.0 */  74.92, 72.39, 70.00, 67.62,
        /*    25.1 */  65.29, 63.02, 60.84, 59.00,
        /*    31.6 */  57.17, 55.34, 53.51, 51.67,
        /*    39.8 */  50.04, 48.12, 46.38, 44.66,
        /*    50.1 */  43.10, 41.73, 40.50, 39.22,
        /*    63.1 */  37.23, 35.77, 34.51, 32.81,
        /*    79.4 */  31.32, 30.36, 29.02, 27.60,
        /*   100.0 */  26.58, 25.91, 24.41, 23.01,
        /*   125.9 */  22.12, 21.25, 20.18, 19.00,
        /*   158.5 */  17.70, 16.82, 15.94, 15.12,
        /*   199.5 */  14.30, 13.41, 12.60, 11.98,
        /*   251.2 */  11.36, 10.57,  9.98,  9.43,
        /*   316.2 */   8.87,  8.46,  7.44,  7.12,
        /*   398.1 */   6.93,  6.68,  6.37,  6.06,
        /*   501.2 */   5.80,  5.55,  5.29,  5.02,
        /*   631.0 */   4.75,  4.48,  4.22,  3.98,
        /*   794.3 */   3.75,  3.51,  3.27,  3.22,
        /*  1000.0 */   3.12,  3.01,  2.91,  2.68,
        /*  1258.9 */   2.46,  2.15,  1.82,  1.46,
        /*  1584.9 */   1.07,  0.61,  0.13, -0.35,
        /*  1995.3 */  -0.96, -1.56, -1.79, -2.35,
        /*  2511.9 */  -2.95, -3.50, -4.01, -4.21,
        /*  3162.3 */  -4.46, -4.99, -5.32, -5.35,
        /*  3981.1 */  -5.13, -4.76, -4.31, -3.13,
        /*  5011.9 */  -1.79,  0.08,  2.03,  4.03,
        /*  6309.6 */   5.80,  7.36,  8.81, 10.22,
        /*  7943.3 */  11.54, 12.51, 13.48, 14.21,
        /* 10000.0 */  14.79, 13.99, 12.85, 11.93,
        /* 12589.3 */  12.87, 15.19, 19.14, 23.69,
        /* 15848.9 */  33.52, 48.65, 59.42, 61.77,
        /* 19952.6 */  63.85, 66.04, 68.33, 70.09,
        /* 25118.9 */  70.66, 71.27, 71.91, 72.60,
    };
    double    freq_log;
    double    dB;
    unsigned  index;
    
    if ( freq <    10. ) freq =    10.;
    if ( freq > 25000. ) freq = 25000.;
    
    freq_log = 40. * log10 (0.1 * freq);   /* 4 steps per third, starting at 10 Hz */
    index    = (unsigned) freq_log;
    assert ( index < sizeof(tab)/sizeof(*tab) );
    dB = tab [index] * (1 + index - freq_log) + tab [index+1] * (freq_log - index);
    return pow ( 10., 0.05*dB );
}

/******************************************************************************************************
 *  keyboard stuff
 ******************************************************************************************************/

typedef struct {
    int             init;
    struct termios  stored_setting;
    struct termios  current_setting;
} keyboard_t;

static keyboard_t* __k;

/* Restore term-settings to those saved when term_init was called */

static void  term_restore (void)
{
    tcsetattr ( 0, TCSANOW, &(__k->stored_setting) );
}  /* term_restore */

/* Clean up terminal; called on exit */

static void  term_exit ( int sig )
{
    term_restore ();
}  /* term_exit */

/* Will be called when ctrl-Z is pressed, this correctly handles the terminal */

static void  term_ctrl_z ( int sig )
{
    signal ( SIGTSTP, term_ctrl_z );
    term_restore ();
    kill ( getpid(), SIGSTOP );
}  /* term_ctrl_z */

/* Will be called when application is continued after having been stopped */

static void  term_cont ( int sig )
{
    signal ( SIGCONT, term_cont );
    tcsetattr ( 0, TCSANOW, &(__k->current_setting) );
} /* term_cont() */

int  open_keyboard    ( keyboard_t* const k )
{
    __k = k;
    tcgetattr ( 0, &(k->stored_setting) );
    tcgetattr ( 0, &(k->current_setting) );

    signal ( SIGINT,  term_exit   );       /* We _must_ clean up when we exit */
    signal ( SIGQUIT, term_exit   );
    signal ( SIGTSTP, term_ctrl_z );       /* Ctrl-Z must also be handled     */
    signal ( SIGCONT, term_cont   );
//  atexit ( term_exit );

    /* One or more characters are sufficient to cause a read to return */
    cfmakeraw ( &(k->current_setting) );
    k->current_setting.c_oflag     |= ONLCR | OPOST;  /* enables NL => CRLF on output */
    
    tcsetattr ( 0, TCSANOW, &(k->current_setting) );
    return 0;
}

int  getchar_keyboard ( keyboard_t* const k )
{
    struct timeval  t;
    fd_set          fd [1];
    int             ret;
    unsigned char   c;

    FD_SET (0, fd);
    t.tv_sec  = 0;
    t.tv_usec = 0;

    ret = select ( 1, fd, NULL, NULL, &t );
    
    switch ( ret ) {
    case  0:
        return -1;
    case  1:
        ret = read (0, &c, 1);
        return ret == 1  ?  c  :  -1;
    default:
        return -2;
    }
}

int  close_keyboard   ( keyboard_t* const k )
{
    term_restore ();
    return 0;
}


/******************************************************************************************************
 *  reporting stuff
 ******************************************************************************************************/

int  report_open ( void )
{
    static char buff [32767];
    fflush  ( stdout );
    setvbuf ( stdout, buff, _IOFBF, sizeof(buff) );
    return 0;
}

int  report ( const generator_t* const g, const amplitude_t* const a )
{
    static double  last_freq  = -1.;
    static double  last_level = -1.;
    double         freq;
    double         level;

    freq  = frequency (g);
    level = 20. * log10 (amplitude (a) * ATH (freq) ) + 80.;
    
    if ( last_freq >= 0 )
        printf ( "%11.3f %8.2f\n", sqrt (freq*last_freq), 0.5 * (level+last_level) );
    printf ( "# %9.3f %8.2f\n", freq, level );
    
    fflush ( stdout );
    
    last_freq  = freq;
    last_level = level;
    return 0;
}

int  report_close ( void )
{
    printf ( "%%%%\n\n" );
    fflush  ( stdout );
    close ( dup ( fileno(stdout) ) );
    setvbuf ( stdout, NULL, _IONBF, 0 );
    return 0;
}


/******************************************************************************************************
 *  main stuff
 ******************************************************************************************************/

typedef enum { 
    left     = 0, 
    right    = 1, 
    phase0   = 2, 
    both     = 2,
    phase90  = 3, 
    phase180 = 4, 
    phasemod = 5 
} earmode_t;

static long double scalar ( const double* a, const double* b )
{
    return  a[ 0]*b[ 0] + a[ 1]*b[ 1] + a[ 2]*b[ 2] + a[ 3]*b[ 3]
           +a[ 4]*b[ 4] + a[ 5]*b[ 5] + a[ 6]*b[ 6] + a[ 7]*b[ 7]
           +a[ 8]*b[ 8] + a[ 9]*b[ 9] + a[10]*b[10] + a[11]*b[11]
           +a[12]*b[12] + a[13]*b[13] + a[14]*b[14] + a[15]*b[15];
}

int experiment ( generator_t* const  g,
		 amplitude_t* const  a,
		 keyboard_t*  const  k,
		 soundcard_t* const  s,
		 earmode_t           earmode )
{    
    long           i;
    int            j;
    stereo_t       samples [512];
    static double  quant_errors [2] [16];
    long double    val;
    double         ampl;
    long           ival;
    
    fprintf ( stderr, "\r+++  up  +++" );
    for ( i = 0; i < g->duration; i += sizeof(samples)/sizeof(*samples) ) {
        fprintf ( stderr, "%3lu%%\b\b\b\b", i*100lu/g->duration );
	
	for (j = 0; j < sizeof(samples)/sizeof(*samples); j++ ) {
	    ampl = iterate_amplifier (a) * ATH (frequency (g));
	    val  = ampl * iterate_generator (g);
	    ival = (long) floor ( val + 0.5 + scalar (quant_errors[0], s->dither) );
	    
	    if ( ival != (sample_t) ival ) {
		report (g, a);
		fprintf ( stderr, "\rOverrun     \n\n" );
		return -1;
	    }
	    memmove ( & quant_errors [0] [1], & quant_errors [0] [0], 
	              sizeof(quant_errors[0]) - sizeof(quant_errors[0][0]) );
	    quant_errors [0] [0] = val - ival; 
	    switch ( earmode ) {
	    case both: 
	        samples [j] [0] = samples [j] [1] = ival; 
		break;
	    case left: 
	        samples [j] [0] = ival;
		samples [j] [1] = 0; 
		break;
	    case right: 
	        samples [j] [0] = 0;
		samples [j] [1] = ival; 
		break;
	    case phase180: 
	        samples [j] [0] = ival == -32768 ? 32767 : -ival;
		samples [j] [1] = +ival; 
		break;
	    case phase90:
	        samples [j] [0] = ival;
	        val  = ampl * get_cosine (g);
	        ival = (long) floor ( val + 0.5 + scalar (quant_errors[1], s->dither) );
	        if ( ival != (sample_t) ival ) {
		    report (g, a);
		    fprintf ( stderr, "\rOverrun     \n\n" );
		    return -1;
	        }
	        memmove ( & quant_errors [1] [1], & quant_errors [1] [0], 
	              sizeof(quant_errors[1]) - sizeof(quant_errors[1][0]) );
  	        quant_errors [1] [0] = val - ival; 
	        samples [j] [1] = ival;
		break;
	    default:
	        assert (0);
		return -1;
	    }
	}
	play_soundcard ( s, samples, sizeof(samples)/sizeof(*samples) );
	if ( amplitude (a) * ATH (frequency (g)) <= 3.16227766e-6 ) {
            report (g, a);
	    fprintf ( stderr, "\rUnderrun      \n\n" );
	    return -1;
	}
	
	switch ( getchar_keyboard (k) ) {
	case '+':
	    fprintf ( stderr, "\r+++  up  +++" );
	    report (g, a);
	    change_direction ( a, up );
	    break;
	case '-':
	    fprintf ( stderr, "\r--- down ---" );
            report (g, a);
	    change_direction ( a, down );
	    break;
	case '\r':
	case '\n':
	    fprintf ( stderr, "\r** change **" );
            report (g, a);
	    change_direction ( a, change );
	    break;
	case 'C'&0x1F:
	case 'q':
	case 'Q':
	case 'x':
	case 'X':
	    fprintf ( stderr, "\rBreak       \n\n" );
	    fflush  ( stderr );
	    return -1;
	default:
	    fprintf ( stderr, "\a" );
	    break;
	case -1:
	    break;
	}
    }
	
    fprintf ( stderr, "\rReady       \n\n" );
    return 0;
}

static void usage ( void )
{
    static const char help[] = 
        "'Absolute Threshold of Hearing' -- Version 0.07   (C) Frank Klemm 2000\n"
	"\n"
	"usage:\n" 
	"    ath  type minfreq maxfreq duration ampl_speed [start_level [earmode] > reportfile\n"
	"\n"
	"         type:         linear, logarithm, square, cubic, erb, recip\n"
	"         minfreq:      initial frequency [Hz]\n"
	"         maxfreq:      end frequency [Hz]\n"
	"         duration:     duration of the experiment [s]\n"
	"         ampl_speed:   amplitude slope speed [phon/s]\n"
	"         start_level:  absolute level at startup [0...1]\n"
	"         earmode:      left, right, both, phase90, phase180\n"
	"\n"
	"example:\n"
        "    ath  erb  700 22000 600 3 0.0001 > result1\n"
	"    ath  erb 1400    16 360 3 0.0001 > result2\n"
	"\n"
	"handling:\n"
	"    press '-' once when you start hearing a tone\n"
	"    press '+' once when you stop hearing a tone\n"
	"    press 'q' to early leave the program\n"
	"    on errors the pressed key is ignored\n";
    
    fprintf ( stderr, "%s\n", help );
}

int main ( int argc, char** argv )
{
    generator_t  g;
    amplitude_t  a;
    soundcard_t  s;
    keyboard_t   k;
    genmode_t    genmode;
    earmode_t    earmode;

    if ( argc == 1 ) {
        usage ();
        system ( "./ath erb  700 22000 600 3 0.0001 > result1" );
	system ( "./ath erb 1400    16 360 3 0.0001 > result2" );
	system ( "xmgr result1 result2 &> /dev/null &" );
	return 0;
    }
    
    if ( argc < 6 ) {
	usage ();
	return 1;
    }
    
    if      ( 0 == strncmp ( argv[1], "li" , 2) ) genmode = linear;
    else if ( 0 == strncmp ( argv[1], "lo" , 2) ) genmode = logarithm;
    else if ( 0 == strncmp ( argv[1], "sq" , 2) ) genmode = square;
    else if ( 0 == strncmp ( argv[1], "cu" , 2) ) genmode = cubic;
    else if ( 0 == strncmp ( argv[1], "er" , 2) ) genmode = erb;
    else if ( 0 == strncmp ( argv[1], "re" , 2) ) genmode = recip;
    else {
	usage ();
	return 1;
    }

    if      ( argc < 8 )                              earmode = both;
    else if ( 0 == strncmp ( argv[7], "le"     , 2) ) earmode = left;
    else if ( 0 == strncmp ( argv[7], "ri"     , 2) ) earmode = right;
    else if ( 0 == strncmp ( argv[7], "bo"     , 2) ) earmode = both;
    else if ( 0 == strncmp ( argv[7], "phase9" , 6) ) earmode = phase90;
    else if ( 0 == strncmp ( argv[7], "phase1" , 6) ) earmode = phase180;
    else {
	usage ();
	return 1;
    }

    
    open_soundcard ( &s, AUDIO_DEVICE, sizeof(stereo_t)/sizeof(sample_t), CHAR_BIT*sizeof(sample_t), 96000.0 );
    open_generator ( &g, &s, genmode, atof (argv[4]), atof (argv[2]), atof (argv[3]) );
    open_amplifier ( &a, &s, argc > 6  ?  atof (argv[6])  :  0.0001, atof (argv[5]) );
    open_keyboard  ( &k );

    report_open    ( );
    experiment     ( &g, &a, &k, &s, earmode );
    report_close   ( );
    
    close_keyboard ( &k );
    close_amplifier( &a );
    close_generator( &g );
    close_soundcard( &s );
    
    return 0;
}

/* end of ath.c */