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

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

+/*
+  Autocorrelation function using FFT routines adapted from routines given in
+  Numerical Recipes.
+  The routine acf() uses an fft to compute the array of lagged products
+  which is 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, which must not be
+  greater than the input framewidth.
+
+  Padding with zeroes is recommended to counter end-effects (See NR, p416).
+  It is also necessary since:
+1) framesize + padding must be a power of two (sample points at given rate).
+2) max possible acf lag = ( framesize + padding ) / 2
+
+  Each input frame is padded with zeroes so that it is at least twice the
+  required max acf lag, and is also a power of 2.
+  This is because the fft method is "radix-2", and because the output acf is
+  symmetrical so that just half the points are unique.
+  Therefore each input frame is padded with zeroes to the next power of 2
+  larger than either the input framewidth, or twice the required max acf lag,
+  (whichever is  the larger).
+
+  If necessary, extra padding can be enforced using the padding option to
+  add extra zeroes, padding to a larger power of 2.
+  The amount of extra padding is "exponential", expanding the basic size to:
+	( framesize + padding ) * 2**n
+  where the padding option is n.
+  (n=0 by default, so that no extra padding is added. When n=1 then padding is
+  added to double the size, and when n=2 the size is quadrupled, etc.).
+
+  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).
+
+  Other options (set using <option>=on):
+    size         Print the input and output frame sizes in sample points.
+    echo         Echo buffered input without processing.
+    negative     Write negative half of acf (ie. with zeroth lag on right).
+
+
+  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
+   within a frame of 12.8ms, plotting the 2nd frame in a sequence of frames
+   with frameshift 12.8ms.
+
+acf samp=10kHz width=12.8ms frstep=12.8ms frame=2 lag=12.8ms file | x11plot
+
+3. An animated plot of successive acf's of a waveform sampled at 10kHz,
+   each computed within a frame of 12.8ms, and shifted by 2 sample points.
+
+acf samp=10kHz width=12.8ms 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, *widthstr, *sizestr ;
+static char *padstr, *wstr, *lagstr, *scalestr, *normstr, *framestr, *echostr, *negstr ;
+
+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"    ,   "16ms"      ,  &shiftstr    ,   "Step between input frames."            , VAL     },
+    {   "width"     ,   "32ms"      ,  &widthstr    ,   "Width of input frames."                , VAL     },
+    {   "lag"       ,   "32ms"      ,  &lagstr      ,   "Maximum acf lag (output frame width)." , VAL     },
+    {   "padding"   ,   "0"         ,  &padstr      ,   "Exponential frame padding"             , SVAL    },
+    {   "window"    ,   "on"        ,  &wstr        ,   "Hamming window"                        , SETFLAG },
+    {   "normalize" ,   "off"       ,  &normstr     ,   "normalized acf"                        , SETFLAG },
+    {   "scale"     ,   "0.025"     ,  &scalestr    ,   "scale output"                          , 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     width       ;
+int     step        ;
+int     zeroes      ;
+int     maxlag      ;
+int     dowindow    ;
+double  scale       ;
+int     normalize   ;
+int     echo        ;
+int     negative    ;
+
+float  *vec, *window ;
+short  *obuf ;
+
+main (argc, argv)
+int     argc;
+char  **argv;
+{
+    FILE     *fp  ;
+    short    *buf ;
+    int       a, b ;
+
+    fp = openopts( option,argc,argv ) ;
+    if ( !isoff( helpstr ) )
+	helpopts( helpstr, argv[0], applic, option ) ;
+
+    samplerate = to_Hz( sampstr ) ;
+    dowindow   = ison(  wstr    ) ;
+    normalize  = ison(  normstr ) ;
+    echo       = ison(  echostr ) ;
+    negative   = ison(  negstr  ) ;
+
+    width      = to_p( widthstr, samplerate )  ;
+    step       = to_p( shiftstr, samplerate )  ;
+    maxlag     = to_p( lagstr  , samplerate )  ;
+
+    if ( ( maxlag << 1 ) < width )
+	zeroes = ( getpower( width ) << atoi( padstr ) ) - width ;
+    else if ( maxlag <= width )
+	zeroes = ( getpower( maxlag << 1 ) << atoi( padstr ) ) - width ;
+    else {
+	fprintf(stderr,"acf: required max lag [%dms] greater than framewidth [%dms]\n", maxlag*1000/samplerate, width*1000/samplerate);
+	exit( 1 ) ;
+    }
+
+    scale = ( 1./(double)(width+zeroes) ) * atof( scalestr ) ;
+
+    /* frame size printout */
+
+    if ( ison( sizestr ) ) {
+	fprintf(stderr,"acf sizes in sample points:\n" ) ;
+	fprintf(stderr,"    input  frame size = %d  (framewidth=%d + padding=%d)\n", width+zeroes, width, zeroes ) ;
+	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( width+zeroes * sizeof(float) ) ;
+    if ( dowindow )
+	window = hamming( width ) ;
+
+    /* 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 ) ;
+    }
+
+    while ( ( buf = getframe( fp, a, width, step ) ) != (short *)0  && ( a<=b || b==0 ) ) {
+	if ( echo ) fwrite( buf, sizeof(short), width, stdout ) ;
+	else process( buf ) ;
+	a++ ;
+    }
+    if ( a<=b && b>0 )
+	fprintf(stderr,"warning: not enough frames for request\n");
+
+    fclose( fp ) ;
+}
+
+
+process( buf )
+short *buf ;
+{
+    short *bptr   = buf ;
+    short *endptr = buf + width ;
+    short *optr   = obuf ;
+    short *endlag = obuf + maxlag ;
+    float *wptr   = window ;
+    float *vptr   = vec    ;
+    float *endvec = vec + width + zeroes ;
+
+    if ( dowindow )
+	while ( bptr < endptr )
+	    *vptr++ =  *bptr++  *  *wptr++ ;
+    else
+	while ( bptr < endptr )
+	    *vptr++ =  *bptr++ ;
+
+    while ( vptr < endvec )         /* padding */
+	*vptr++ =  0 ;
+
+    acf( vec, width+zeroes ) ;
+
+    if ( normalize )
+	scale = 1000. / *vec ;
+
+    vptr = vec ;
+    while ( optr < endlag )
+	*optr++ = (short)( scale * *vptr++ ) ;
+
+    if ( !negative )
+	fwrite( obuf, sizeof(short), maxlag, stdout ) ;
+    else {
+	for ( optr = endlag-1 ; optr >= obuf ; optr-- ) /* write in reverse */
+	    fwrite( optr, sizeof(short), 1, stdout ) ;
+    }
+}
+
+