comparison tools/racf.c @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

+/*
+  Autocorrelation function using recursive "leaky integrator" filter
+  ie. for the m'th lag, the n'th recursive update is:
+
+	y[n] = a.y[n-1] + (1-a).f[n].f[n-m]
+
+  where decay constant a = exp(-Ts/T)
+  and   Ts is sample interval in seconds
+	T  is decay time constant in seconds
+
+  The recursion computes the mean value of the product f[n].f[n-m]
+  within an exponential window which weights past values.
+  The window width parameter (eg. corresponding with the width of the
+  fft analysis window) is the time constant parameter.
+  The half life of the exponential window is given by -T.ln(0.5) = 0.693T
+  ie. for a given time constant, T secs, the window decays to half of its
+  current value in a period of 0.693T secs.
+  So T can be set to accomodate an expected period.
+  As a rough guide, in a period of 0.5T the window decays to about 0.6
+  (ie by 60%), so set T to twice the expected period of the waveform to
+  get 60% of the window over this period.
+  Eg. if the waveform has an expected period of t ms, then to set 60% of
+  the window to this period, set 0.5T = t ms, ie. T = 2t ms.
+
+  The routine generates the autocovariance function.
+  An optional normalization (dividing each coefficient by the zeroth
+  coefficient) produces the autocorrelation function,
+  (and this is then scaled up to the range [0-1000]).
+
+  The output framewidth is the given maximum acf lag.
+
+  Frames are selected from the input stream using the "frames" option,
+  which has syntax: [[-]frame=a[-b]]. Input frames  are numbered 1,2,...
+  For example:
+    frame=a      Select just the a'th frame.
+    frame=a-b    Select frames from the a'th to b'th inclusive.
+  The strings "min" and "max" can be used as specifiers, meaning eg:
+    frame=min    Select the first frame.
+    frame=max    Select the last frame.
+    frame=a-max  Select frames from the a'th to the last inclusive.
+    frame=min-b  Select frames from the first to the b'th inclusive.
+  The default selects all frames, (ie frame=min-max).
+
+
+  Examples:
+
+1. To print the input and output frame sizes in sample points, eg for a
+   subsequent plotting program, use the size option:
+
+acf ... size=on
+
+2. An acf of a waveform sampled at 10kHz, computed to a max lag of 12.8ms,
+   plotting the 2nd frame in a sequence of frames with frameshift 12.8ms.
+
+acf samp=10kHz frstep=12.8ms frame=2 lag=12.8ms file | x11plot
+
+3. An animated plot of successive acf's of a waveform sampled at 10kHz,
+   shifted by 2 sample points.
+
+acf samp=10kHz frstep=2p lag=12.8ms file | x11play -n128
+
+*/
+
+#include <stdio.h>
+#include <math.h>
+#include "options.h"
+#include "units.h"
+#include "strmatch.h"
+#include "sigproc.h"
+
+char applic[]     = "autocorrelation function of contiguous frames.\n      i/p and o/p data in binary shorts." ;
+
+static char *helpstr, *debugstr, *sampstr,  *startstr, *shiftstr, *sizestr ;
+static char *lagstr,  *tcstr,    *scalestr, *normstr,  *framestr, *echostr ;
+static char *negstr,  *upstr,    *slopestr ;
+
+static Options option[] = {
+    {   "help"      ,   "off"       ,  &helpstr     ,   "help"                                  , DEBUG   },
+    {   "debug"     ,   "off"       ,  &debugstr    ,   "debugging switch"                      , DEBUG   },
+    {   "samplerate",   "20kHz"     ,  &sampstr     ,   "Samplerate "                           , VAL     },
+    {   "start"     ,   "0"         ,  &startstr    ,   "Start point in i/p file."              , VAL     },
+    {   "frames"    ,   "1-max"     ,  &framestr    ,   "Select frames inclusively"             , VAL     },
+    {   "frstep"    ,   "1ms"       ,  &shiftstr    ,   "Step between output frames."           , VAL     },
+    {   "lag"       ,   "32ms"      ,  &lagstr      ,   "Maximum acf lag (output frame width)." , VAL     },
+    {   "update"    ,   "1p"        ,  &upstr       ,   "Step between recursive updates."       , VAL     },
+    {   "timeconst" ,   "3ms"       ,  &tcstr       ,   "Decay time constant"                   , VAL     },
+    {   "normalize" ,   "off"       ,  &normstr     ,   "Normalized acf"                        , SETFLAG },
+    {   "scale"     ,   "0.003"     ,  &scalestr    ,   "scale output"                          , SVAL    },
+    {   "sigmoid"   ,   "off"       ,  &slopestr    ,   "Sigmoidal weighting slope parameter"   , SVAL    },
+    {   "size"      ,   "off"       ,  &sizestr     ,   "Print input/output frame size in samples"      , SETFLAG },
+    {   "echo"      ,   "off"       ,  &echostr     ,   "echo buffered input without processing", SVAL    },
+    {   "negative"  ,   "off"       ,  &negstr      ,   "write negative half of acf (zeroth lag on right)", SVAL    },
+   ( char * ) 0 } ;
+
+
+int     samplerate  ;
+int     framestep   ;
+int     updatestep  ;
+int     maxlag      ;
+double  scale       ;
+int     normalize   ;
+int     echo        ;
+int     negative    ;
+double  alpha       ;   /* decay constant */
+
+float  *vec   ;
+short  *obuf  ;
+
+main (argc, argv)
+int     argc;
+char  **argv;
+{
+    FILE     *fp  ;
+    int       a, b ;
+
+    fp = openopts( option,argc,argv ) ;
+    if ( !isoff( helpstr ) )
+	helpopts( helpstr, argv[0], applic, option ) ;
+
+    samplerate = to_Hz( sampstr ) ;
+    normalize  = ison(  normstr ) ;
+    echo       = ison(  echostr ) ;
+    negative   = ison(  negstr  ) ;
+
+    framestep  = to_p( shiftstr, samplerate )  ;
+    updatestep = to_p( upstr   , samplerate )  ;
+    maxlag     = to_p( lagstr  , samplerate )  ;
+
+    scale      = atof( scalestr ) ;
+
+    alpha      = exp( -(double)( 1. / ( samplerate * to_s( tcstr, samplerate ) ) ) ) ;
+
+    if ( framestep % updatestep != 0 ) {
+	fprintf(stderr,"frstep [%dp] must be an integer multiple of update [%dp] \n", framestep, updatestep ) ;
+	exit( 1 ) ;
+    }
+
+    /* frame size printout */
+
+    if ( ison( sizestr ) ) {
+	fprintf(stderr,"acf sizes in sample points:\n" ) ;
+	fprintf(stderr,"    output frame size = %d \n", maxlag ) ;
+	exit( 0 ) ;
+    }
+
+    /* parse bounds on number of frames */
+
+    if ( selector( framestr, &a, &b ) == 0 ) {
+	fprintf(stderr,"acf: bad frame selector [%s]\n", framestr ) ;
+	exit( 1 ) ;
+    }
+
+    /* Allocate working space */
+
+    obuf  = (short *)malloc( maxlag * sizeof(short) ) ;
+    vec   = (float *)malloc( maxlag * sizeof(float) ) ;
+
+    /* Compute acf for each frame of width shorts in the input stream */
+
+    if ( seekbytes( fp, (int)( to_p( startstr, samplerate ) * sizeof(short) ) ) == 0 ) {
+	fprintf(stderr,"improper seek\n") ;
+	exit( 1 ) ;
+    }
+
+    if ( isoff( slopestr ) )
+	process( fp, a, b ) ;                   /* conventional acf recursion */
+    else
+	process2( fp, a, b, atof( slopestr) ) ; /* sigmoidally weighted recursion */
+						/* (recommend set sigmoid=.02)    */
+
+    fclose( fp ) ;
+}
+
+
+process( fp, a, b )
+FILE *fp ;
+int   a, b ;
+{
+    register  short  *buf, *bptr, *endptr ;
+    register  float  *vptr ;
+    register  double  beta ;
+    register  int     update_count = 0 ;
+    register  int     frame_count  = 0 ;
+
+    /* Initialize process with the first maxlag samples */
+
+    if ( ( buf = getframe( fp, 1, maxlag, updatestep ) ) != (short *)0 ) {
+	for ( endptr = buf ; endptr < buf + maxlag ; endptr++ ) {
+	    bptr = endptr ;
+	    vptr = vec ;
+	    beta = ( 1-alpha ) * *bptr ;
+	    while ( bptr >= buf )
+		*vptr++ =  alpha * *vptr + beta * *bptr-- ;
+	}
+
+	update_count = 1 ;
+	frame_count  = 1 ;
+
+	if ( frame_count >= a ) {
+	    if ( echo )
+		fwrite( buf, sizeof(short), maxlag, stdout ) ;
+	    else
+		writeframe() ;
+	}
+    }
+
+    /* Continue process with successive buffers of maxlag samples */
+
+    while ( ( buf = getframe( fp, ++update_count, maxlag, updatestep ) ) != (short *)0 && ( frame_count<=b || b==0 ) ) {
+	bptr = buf + maxlag - 1 ;
+	vptr = vec ;
+	beta = ( 1-alpha ) * *bptr ;
+
+	while ( bptr >= buf )     /* recursive update */
+	    *vptr++ =  alpha * *vptr + beta * *bptr-- ;
+
+	if ( update_count % framestep == 1 ) {
+	    if ( ++frame_count >= a && ( frame_count <= b || b == 0 ) ) {
+		if ( echo )
+		    fwrite( buf, sizeof(short), maxlag, stdout ) ;
+		else
+		    writeframe() ;
+	    }
+	}
+    }
+    if ( frame_count <= b && b > 0 )
+	fprintf(stderr,"warning: not enough frames for request\n");
+}
+
+
+writeframe()
+{
+    register  float  *vptr   = vec ;
+    register  short  *optr   = obuf ;
+    register  short  *endlag = obuf + maxlag ;
+
+    if ( normalize )
+	scale = 1000. / *vec ;
+
+    while ( optr < endlag )
+	*optr++ = (short)( scale * *vptr++ ) ;
+
+    if ( !negative )
+	fwrite( obuf, sizeof(short), maxlag, stdout ) ;
+    else {
+	for ( optr = endlag-1 ; optr >= obuf ; optr-- )
+	    fwrite( optr, sizeof(short), 1, stdout ) ;
+    }
+}
+
+
+/*************************************************************************/
+/*
+  same as `process', but with added sigmoidal weighting
+*/
+
+process2( fp, a, b, slope )
+FILE *fp ;
+int   a, b  ;
+float slope ;
+{
+    register  short  *buf, *bptr, *endptr ;
+    register  float  *vptr ;
+    register  double  beta ;
+    register  int     update_count = 0 ;
+    register  int     frame_count  = 0 ;
+    double    sigmoid() ;
+
+    /* Initialize process with the first maxlag samples */
+
+    if ( ( buf = getframe( fp, 1, maxlag, updatestep ) ) != (short *)0 ) {
+	for ( endptr = buf ; endptr < buf + maxlag ; endptr++ ) {
+	    bptr = endptr ;
+	    vptr = vec ;
+	    beta = ( 1-alpha ) * *bptr ;
+	    while ( bptr >= buf )
+		*vptr++ =  alpha * *vptr + beta * sigmoid( fabs((double)*endptr) - fabs((double)*bptr ), slope ) * *bptr-- ;
+	}
+
+	update_count = 1 ;
+	frame_count  = 1 ;
+
+	if ( frame_count >= a ) {
+	    if ( echo )
+		fwrite( buf, sizeof(short), maxlag, stdout ) ;
+	    else
+		writeframe() ;
+	}
+    }
+
+    /* Continue process with successive buffers of maxlag samples */
+
+    while ( ( buf = getframe( fp, ++update_count, maxlag, updatestep ) ) != (short *)0 && ( frame_count<=b || b==0 ) ) {
+	endptr = buf + maxlag - 1 ;
+	bptr   = endptr ;
+	vptr   = vec ;
+	beta   = ( 1-alpha ) * *bptr ;
+
+	while ( bptr >= buf )     /* recursive update */
+	    *vptr++ =  alpha * *vptr + beta * sigmoid( fabs((double)*endptr) - fabs((double)*bptr ), slope ) * *bptr-- ;
+
+	if ( update_count % framestep == 1 ) {
+	    if ( ++frame_count >= a && ( frame_count <= b || b == 0 ) ) {
+		if ( echo )
+		    fwrite( buf, sizeof(short), maxlag, stdout ) ;
+		else
+		    writeframe() ;
+	    }
+	}
+    }
+    if ( frame_count <= b && b > 0 )
+	fprintf(stderr,"warning: not enough frames for request\n");
+}
+
+
+double sigmoid( x, slope )
+double x ;
+float  slope ;
+{
+    return (double)( 1. / ( exp( -(double)( 4.595 + slope * x ) ) + 1. ) ) ;
+}