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/* resamplesubs.c - sampling rate conversion subroutines */
// Altered version
#include "resample.h"
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#define IBUFFSIZE 4096 /* Input buffer size */
#include "smallfilter.h"
#include "largefilter.h"
#include "filterkit.h"
#include "sndlibextra.h"
/* CAUTION: Assumes we call this for only one resample job per program run! */
/* return: 0 - notDone */
/* >0 - index of last sample */
static int
readData(int infd, /* input file descriptor */
int inCount, /* _total_ number of frames in input file */
HWORD *outPtr1, /* array receiving left chan samps */
HWORD *outPtr2, /* array receiving right chan samps */
int dataArraySize, /* size of these arrays */
int nChans,
int Xoff) /* read into input array starting at this index */
{
int i, Nsamps, nret;
static unsigned int framecount; /* frames previously read */
static mus_sample_t **ibufs = NULL;
if (ibufs == NULL) { /* first time called, so allocate it */
ibufs = sndlib_allocate_buffers(nChans, dataArraySize);
if (ibufs == NULL) {
fprintf(stderr, "readData: Can't allocate input buffers!\n");
exit(1);
}
framecount = 0; /* init this too */
}
Nsamps = dataArraySize - Xoff; /* Calculate number of samples to get */
outPtr1 += Xoff; /* Start at designated sample number */
outPtr2 += Xoff;
nret = mus_file_read(infd, 0, Nsamps - 1, nChans, ibufs);
if (nret < 0) {
fprintf(stderr, "readData: Can't read data!\n");
exit(1);
}
/* NB: sndlib pads ibufs with zeros if it reads past EOF. */
if (nChans == 1) {
for (i = 0; i < Nsamps; i++)
*outPtr1++ = MUS_SAMPLE_TYPE_TO_HWORD(ibufs[0][i]);
}
else {
for (i = 0; i < Nsamps; i++) {
*outPtr1++ = MUS_SAMPLE_TYPE_TO_HWORD(ibufs[0][i]);
*outPtr2++ = MUS_SAMPLE_TYPE_TO_HWORD(ibufs[1][i]);
}
}
framecount += Nsamps;
if (framecount >= (unsigned)inCount) /* return index of last samp */
return (((Nsamps - (framecount - inCount)) - 1) + Xoff);
else
return 0;
}
#ifdef DEBUG
static int pof = 0; /* positive overflow count */
static int nof = 0; /* negative overflow count */
#endif
static INLINE HWORD WordToHword(WORD v, int scl)
{
HWORD out;
WORD llsb = (1<<(scl-1));
v += llsb; /* round */
v >>= scl;
if (v>MAX_HWORD) {
#ifdef DEBUG
if (pof == 0)
fprintf(stderr, "*** resample: sound sample overflow\n");
else if ((pof % 10000) == 0)
fprintf(stderr, "*** resample: another ten thousand overflows\n");
pof++;
#endif
v = MAX_HWORD;
} else if (v < MIN_HWORD) {
#ifdef DEBUG
if (nof == 0)
fprintf(stderr, "*** resample: sound sample (-) overflow\n");
else if ((nof % 1000) == 0)
fprintf(stderr, "*** resample: another thousand (-) overflows\n");
nof++;
#endif
v = MIN_HWORD;
}
out = (HWORD) v;
return out;
}
/* Sampling rate conversion using linear interpolation for maximum speed.
*/
static int
SrcLinear(HWORD X[], HWORD Y[], double factor, UWORD *Time, UHWORD Nx)
{
HWORD iconst;
HWORD *Xp, *Ystart;
WORD v,x1,x2;
double dt; /* Step through input signal */
UWORD dtb; /* Fixed-point version of Dt */
UWORD endTime; /* When Time reaches EndTime, return to user */
dt = 1.0/factor; /* Output sampling period */
dtb = dt*(1<<Np) + 0.5; /* Fixed-point representation */
Ystart = Y;
endTime = *Time + (1<<Np)*(WORD)Nx;
while (*Time < endTime)
{
iconst = (*Time) & Pmask;
Xp = &X[(*Time)>>Np]; /* Ptr to current input sample */
x1 = *Xp++;
x2 = *Xp;
x1 *= ((1<<Np)-iconst);
x2 *= iconst;
v = x1 + x2;
*Y++ = WordToHword(v,Np); /* Deposit output */
*Time += dtb; /* Move to next sample by time increment */
}
return (Y - Ystart); /* Return number of output samples */
}
/* Sampling rate up-conversion only subroutine;
* Slightly faster than down-conversion;
*/
static int SrcUp(HWORD X[], HWORD Y[], double factor, UWORD *Time,
UHWORD Nx, UHWORD Nwing, UHWORD LpScl,
HWORD Imp[], HWORD ImpD[], BOOL Interp)
{
HWORD *Xp, *Ystart;
WORD v;
double dt; /* Step through input signal */
UWORD dtb; /* Fixed-point version of Dt */
UWORD endTime; /* When Time reaches EndTime, return to user */
dt = 1.0/factor; /* Output sampling period */
dtb = dt*(1<<Np) + 0.5; /* Fixed-point representation */
Ystart = Y;
endTime = *Time + (1<<Np)*(WORD)Nx;
while (*Time < endTime)
{
Xp = &X[*Time>>Np]; /* Ptr to current input sample */
/* Perform left-wing inner product */
v = FilterUp(Imp, ImpD, Nwing, Interp, Xp, (HWORD)(*Time&Pmask),-1);
/* Perform right-wing inner product */
v += FilterUp(Imp, ImpD, Nwing, Interp, Xp+1,
/* previous (triggers warning): (HWORD)((-*Time)&Pmask),1); */
(HWORD)((((*Time)^Pmask)+1)&Pmask),1);
v >>= Nhg; /* Make guard bits */
v *= LpScl; /* Normalize for unity filter gain */
*Y++ = WordToHword(v,NLpScl); /* strip guard bits, deposit output */
*Time += dtb; /* Move to next sample by time increment */
}
return (Y - Ystart); /* Return the number of output samples */
}
/* Sampling rate conversion subroutine */
static int SrcUD(HWORD X[], HWORD Y[], double factor, UWORD *Time,
UHWORD Nx, UHWORD Nwing, UHWORD LpScl,
HWORD Imp[], HWORD ImpD[], BOOL Interp)
{
HWORD *Xp, *Ystart;
WORD v;
double dh; /* Step through filter impulse response */
double dt; /* Step through input signal */
UWORD endTime; /* When Time reaches EndTime, return to user */
UWORD dhb, dtb; /* Fixed-point versions of Dh,Dt */
dt = 1.0/factor; /* Output sampling period */
dtb = dt*(1<<Np) + 0.5; /* Fixed-point representation */
dh = MIN(Npc, factor*Npc); /* Filter sampling period */
dhb = dh*(1<<Na) + 0.5; /* Fixed-point representation */
Ystart = Y;
endTime = *Time + (1<<Np)*(WORD)Nx;
while (*Time < endTime)
{
Xp = &X[*Time>>Np]; /* Ptr to current input sample */
v = FilterUD(Imp, ImpD, Nwing, Interp, Xp, (HWORD)(*Time&Pmask),
-1, dhb); /* Perform left-wing inner product */
v += FilterUD(Imp, ImpD, Nwing, Interp, Xp+1,
/* previous (triggers warning): (HWORD)((-*Time)&Pmask), */
(HWORD)((((*Time)^Pmask)+1)&Pmask),
1, dhb); /* Perform right-wing inner product */
v >>= Nhg; /* Make guard bits */
v *= LpScl; /* Normalize for unity filter gain */
*Y++ = WordToHword(v,NLpScl); /* strip guard bits, deposit output */
*Time += dtb; /* Move to next sample by time increment */
}
return (Y - Ystart); /* Return the number of output samples */
}
static int err_ret(char *s)
{
fprintf(stderr,"resample: %s \n\n",s); /* Display error message */
return -1;
}
static int resampleFast( /* number of output samples returned */
double factor, /* factor = Sndout/Sndin */
int infd, /* input and output file descriptors */
int outfd,
int inCount, /* number of input samples to convert */
int outCount, /* number of output samples to compute */
int nChans) /* number of sound channels (1 or 2) */
{
UWORD Time, Time2; /* Current time/pos in input sample */
UHWORD Xp, Ncreep, Xoff, Xread;
int OBUFFSIZE = (int)(((double)IBUFFSIZE)*factor+2.0);
HWORD X1[IBUFFSIZE], Y1[OBUFFSIZE]; /* I/O buffers */
HWORD X2[IBUFFSIZE], Y2[OBUFFSIZE]; /* I/O buffers */
UHWORD Nout, Nx;
int i, Ycount, last;
mus_sample_t **obufs = sndlib_allocate_buffers(nChans, OBUFFSIZE);
if (obufs == NULL)
return err_ret("Can't allocate output buffers");
Xoff = 10;
Nx = IBUFFSIZE - 2*Xoff; /* # of samples to process each iteration */
last = 0; /* Have not read last input sample yet */
Ycount = 0; /* Current sample and length of output file */
Xp = Xoff; /* Current "now"-sample pointer for input */
Xread = Xoff; /* Position in input array to read into */
Time = (Xoff<<Np); /* Current-time pointer for converter */
for (i=0; i<Xoff; X1[i++]=0); /* Need Xoff zeros at begining of sample */
for (i=0; i<Xoff; X2[i++]=0); /* Need Xoff zeros at begining of sample */
do {
if (!last) /* If haven't read last sample yet */
{
last = readData(infd, inCount, X1, X2, IBUFFSIZE,
nChans, (int)Xread);
if (last && (last-Xoff<Nx)) { /* If last sample has been read... */
Nx = last-Xoff; /* ...calc last sample affected by filter */
if (Nx <= 0)
break;
}
}
/* Resample stuff in input buffer */
Time2 = Time;
Nout=SrcLinear(X1,Y1,factor,&Time,Nx);
if (nChans==2)
Nout=SrcLinear(X2,Y2,factor,&Time2,Nx);
Time -= (Nx<<Np); /* Move converter Nx samples back in time */
Xp += Nx; /* Advance by number of samples processed */
Ncreep = (Time>>Np) - Xoff; /* Calc time accumulation in Time */
if (Ncreep) {
Time -= (Ncreep<<Np); /* Remove time accumulation */
Xp += Ncreep; /* and add it to read pointer */
}
for (i=0; i<IBUFFSIZE-Xp+Xoff; i++) { /* Copy part of input signal */
X1[i] = X1[i+Xp-Xoff]; /* that must be re-used */
if (nChans==2)
X2[i] = X2[i+Xp-Xoff]; /* that must be re-used */
}
if (last) { /* If near end of sample... */
last -= Xp; /* ...keep track were it ends */
if (!last) /* Lengthen input by 1 sample if... */
last++; /* ...needed to keep flag TRUE */
}
Xread = i; /* Pos in input buff to read new data into */
Xp = Xoff;
Ycount += Nout;
if (Ycount>outCount) {
Nout -= (Ycount-outCount);
Ycount = outCount;
}
if (Nout > OBUFFSIZE) /* Check to see if output buff overflowed */
return err_ret("Output array overflow");
if (nChans==1) {
for (i = 0; i < Nout; i++)
obufs[0][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y1[i]);
} else {
for (i = 0; i < Nout; i++) {
obufs[0][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y1[i]);
obufs[1][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y2[i]);
}
}
/* NB: errors reported within sndlib */
mus_file_write(outfd, 0, Nout - 1, nChans, obufs);
printf("."); fflush(stdout);
} while (Ycount<outCount); /* Continue until done */
return(Ycount); /* Return # of samples in output file */
}
static int resampleWithFilter( /* number of output samples returned */
double factor, /* factor = outSampleRate/inSampleRate */
int infd, /* input and output file descriptors */
int outfd,
int inCount, /* number of input samples to convert */
int outCount, /* number of output samples to compute */
int nChans, /* number of sound channels (1 or 2) */
BOOL interpFilt, /* TRUE means interpolate filter coeffs */
HWORD Imp[], HWORD ImpD[],
UHWORD LpScl, UHWORD Nmult, UHWORD Nwing)
{
UWORD Time, Time2; /* Current time/pos in input sample */
UHWORD Xp, Ncreep, Xoff, Xread;
int OBUFFSIZE = (int)(((double)IBUFFSIZE)*factor+2.0);
HWORD X1[IBUFFSIZE], Y1[OBUFFSIZE]; /* I/O buffers */
HWORD X2[IBUFFSIZE], Y2[OBUFFSIZE]; /* I/O buffers */
UHWORD Nout, Nx;
int i, Ycount, last;
mus_sample_t **obufs = sndlib_allocate_buffers(nChans, OBUFFSIZE);
if (obufs == NULL)
return err_ret("Can't allocate output buffers");
/* Account for increased filter gain when using factors less than 1 */
if (factor < 1)
LpScl = LpScl*factor + 0.5;
/* Calc reach of LP filter wing & give some creeping room */
Xoff = ((Nmult+1)/2.0) * MAX(1.0,1.0/factor) + 10;
if (IBUFFSIZE < 2*Xoff) /* Check input buffer size */
return err_ret("IBUFFSIZE (or factor) is too small");
Nx = IBUFFSIZE - 2*Xoff; /* # of samples to process each iteration */
last = 0; /* Have not read last input sample yet */
Ycount = 0; /* Current sample and length of output file */
Xp = Xoff; /* Current "now"-sample pointer for input */
Xread = Xoff; /* Position in input array to read into */
Time = (Xoff<<Np); /* Current-time pointer for converter */
for (i=0; i<Xoff; X1[i++]=0); /* Need Xoff zeros at begining of sample */
for (i=0; i<Xoff; X2[i++]=0); /* Need Xoff zeros at begining of sample */
do {
if (!last) /* If haven't read last sample yet */
{
last = readData(infd, inCount, X1, X2, IBUFFSIZE,
nChans, (int)Xread);
if (last && (last-Xoff<Nx)) { /* If last sample has been read... */
Nx = last-Xoff; /* ...calc last sample affected by filter */
if (Nx <= 0)
break;
}
}
/* Resample stuff in input buffer */
Time2 = Time;
if (factor >= 1) { /* SrcUp() is faster if we can use it */
Nout=SrcUp(X1,Y1,factor,&Time,Nx,Nwing,LpScl,Imp,ImpD,interpFilt);
if (nChans==2)
Nout=SrcUp(X2,Y2,factor,&Time2,Nx,Nwing,LpScl,Imp,ImpD,
interpFilt);
}
else {
Nout=SrcUD(X1,Y1,factor,&Time,Nx,Nwing,LpScl,Imp,ImpD,interpFilt);
if (nChans==2)
Nout=SrcUD(X2,Y2,factor,&Time2,Nx,Nwing,LpScl,Imp,ImpD,
interpFilt);
}
Time -= (Nx<<Np); /* Move converter Nx samples back in time */
Xp += Nx; /* Advance by number of samples processed */
Ncreep = (Time>>Np) - Xoff; /* Calc time accumulation in Time */
if (Ncreep) {
Time -= (Ncreep<<Np); /* Remove time accumulation */
Xp += Ncreep; /* and add it to read pointer */
}
for (i=0; i<IBUFFSIZE-Xp+Xoff; i++) { /* Copy part of input signal */
X1[i] = X1[i+Xp-Xoff]; /* that must be re-used */
if (nChans==2)
X2[i] = X2[i+Xp-Xoff]; /* that must be re-used */
}
if (last) { /* If near end of sample... */
last -= Xp; /* ...keep track were it ends */
if (!last) /* Lengthen input by 1 sample if... */
last++; /* ...needed to keep flag TRUE */
}
Xread = i; /* Pos in input buff to read new data into */
Xp = Xoff;
Ycount += Nout;
if (Ycount>outCount) {
Nout -= (Ycount-outCount);
Ycount = outCount;
}
if (Nout > OBUFFSIZE) /* Check to see if output buff overflowed */
return err_ret("Output array overflow");
if (nChans==1) {
for (i = 0; i < Nout; i++)
obufs[0][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y1[i]);
} else {
for (i = 0; i < Nout; i++) {
obufs[0][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y1[i]);
obufs[1][i] = HWORD_TO_MUS_SAMPLE_TYPE(Y2[i]);
}
}
/* NB: errors reported within sndlib */
mus_file_write(outfd, 0, Nout - 1, nChans, obufs);
printf("."); fflush(stdout);
} while (Ycount<outCount); /* Continue until done */
return(Ycount); /* Return # of samples in output file */
}
int resample( /* number of output samples returned */
double factor, /* factor = Sndout/Sndin */
int infd, /* input and output file descriptors */
int outfd,
int inCount, /* number of input samples to convert */
int outCount, /* number of output samples to compute */
int nChans, /* number of sound channels (1 or 2) */
BOOL interpFilt, /* TRUE means interpolate filter coeffs */
int fastMode, /* 0 = highest quality, slowest speed */
BOOL largeFilter, /* TRUE means use 65-tap FIR filter */
char *filterFile) /* NULL for internal filter, else filename */
{
UHWORD LpScl; /* Unity-gain scale factor */
UHWORD Nwing; /* Filter table size */
UHWORD Nmult; /* Filter length for up-conversions */
HWORD *Imp=0; /* Filter coefficients */
HWORD *ImpD=0; /* ImpD[n] = Imp[n+1]-Imp[n] */
if (fastMode)
return resampleFast(factor,infd,outfd,inCount,outCount,nChans);
#ifdef DEBUG
/* Check for illegal constants */
if (Np >= 16)
return err_ret("Error: Np>=16");
if (Nb+Nhg+NLpScl >= 32)
return err_ret("Error: Nb+Nhg+NLpScl>=32");
if (Nh+Nb > 32)
return err_ret("Error: Nh+Nb>32");
#endif
/* Set defaults */
if (filterFile != NULL && *filterFile != '\0') {
if (readFilter(filterFile, &Imp, &ImpD, &LpScl, &Nmult, &Nwing))
return err_ret("could not find filter file, "
"or syntax error in contents of filter file");
} else if (largeFilter) {
Nmult = LARGE_FILTER_NMULT;
Imp = LARGE_FILTER_IMP; /* Impulse response */
ImpD = LARGE_FILTER_IMPD; /* Impulse response deltas */
LpScl = LARGE_FILTER_SCALE; /* Unity-gain scale factor */
Nwing = LARGE_FILTER_NWING; /* Filter table length */
} else {
Nmult = SMALL_FILTER_NMULT;
Imp = SMALL_FILTER_IMP; /* Impulse response */
ImpD = SMALL_FILTER_IMPD; /* Impulse response deltas */
LpScl = SMALL_FILTER_SCALE; /* Unity-gain scale factor */
Nwing = SMALL_FILTER_NWING; /* Filter table length */
}
#if DEBUG
fprintf(stderr,"Attenuating resampler scale factor by 0.95 "
"to reduce probability of clipping\n");
#endif
LpScl *= 0.95;
return resampleWithFilter(factor,infd,outfd,inCount,outCount,nChans,
interpFilt, Imp, ImpD, LpScl, Nmult, Nwing);
}
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