ref: ca201805c6603ddcb2617976a40566f4b58703cb
dir: /src/cvsd.c/
/*
* CVSD (Continuously Variable Slope Delta modulation)
* conversion routines
*
* The CVSD format is described in the MIL Std 188 113, which is
* available from http://bbs.itsi.disa.mil:5580/T3564
*
* Copyright (C) 1996
* Thomas Sailer (sailer@ife.ee.ethz.ch) (HB9JNX/AE4WA)
* Swiss Federal Institute of Technology, Electronics Lab
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
* Change History:
*
* June 1, 1998 - Chris Bagwell (cbagwell@sprynet.com)
* Fixed compile warnings reported by Kjetil Torgrim Homme
* <kjetilho@ifi.uio.no>
*
*
*/
/* ---------------------------------------------------------------------- */
#include <limits.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h> /* For SEEK_* defines if not found in stdio */
#endif
#include "cvsdfilt.h"
#include "st.h"
#include "libst.h"
/* ---------------------------------------------------------------------- */
#ifndef HAVE_MEMMOVE
#define memmove(dest,src,len) (bcopy((src),(dest),(len)))
#endif
/* ---------------------------------------------------------------------- */
/*
* private data structures
*/
struct cvsd_common_state {
unsigned overload;
float mla_int;
float mla_tc0;
float mla_tc1;
unsigned phase;
unsigned phase_inc;
float v_min, v_max;
};
struct cvsd_decode_state {
float output_filter[DEC_FILTERLEN];
};
struct cvsd_encode_state {
float recon_int;
float input_filter[ENC_FILTERLEN];
};
struct cvsdpriv {
struct cvsd_common_state com;
union {
struct cvsd_decode_state dec;
struct cvsd_encode_state enc;
} c;
struct {
unsigned shreg;
unsigned mask;
unsigned cnt;
} bit;
unsigned bytes_written;
unsigned cvsd_rate;
char swapbits;
};
/* ---------------------------------------------------------------------- */
float float_conv(fp1, fp2, n)
float *fp1;
float *fp2;
int n;
{
float res = 0;
for(; n > 0; n--)
res += (*fp1++) * (*fp2++);
return res;
}
/* ---------------------------------------------------------------------- */
/*
* some remarks about the implementation of the CVSD decoder
* the principal integrator is integrated into the output filter
* to achieve this, the coefficients of the output filter are multiplied
* with (1/(1-1/z)) in the initialisation code.
* the output filter must have a sharp zero at f=0 (i.e. the sum of the
* filter parameters must be zero). This prevents an accumulation of
* DC voltage at the principal integration.
*/
/* ---------------------------------------------------------------------- */
static void cvsdstartcommon(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
/* sanity check */
if (sizeof(struct cvsdpriv) > PRIVSIZE)
fail("struct cvsdpriv is too big (%d); change PRIVSIZE in st.h and recompile sox", sizeof(struct cvsdpriv));
p->cvsd_rate = (ft->info.rate <= 24000) ? 16000 : 32000;
ft->info.rate = 8000;
ft->info.channels = 1;
ft->info.size = WORD; /* make output format default to words */
ft->info.style = SIGN2;
p->swapbits = ft->swap;
ft->swap = 0;
/*
* initialize the decoder
*/
p->com.overload = 0x5;
p->com.mla_int = 0;
/*
* timeconst = (1/e)^(200 / SR) = exp(-200/SR)
* SR is the sampling rate
*/
p->com.mla_tc0 = exp((-200.0)/((float)(p->cvsd_rate)));
/*
* phase_inc = 32000 / SR
*/
p->com.phase_inc = 32000 / p->cvsd_rate;
/*
* initialize bit shift register
*/
p->bit.shreg = p->bit.cnt = 0;
p->bit.mask = p->swapbits ? 0x80 : 1;
/*
* count the bytes written
*/
p->bytes_written = 0;
p->com.v_min = 1;
p->com.v_max = -1;
report("cvsd: bit rate %dbit/s, bits from %s\n", p->cvsd_rate,
p->swapbits ? "msb to lsb" : "lsb to msb");
}
/* ---------------------------------------------------------------------- */
void cvsdstartread(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
float *fp1;
int i;
cvsdstartcommon(ft);
p->com.mla_tc1 = 0.1 * (1 - p->com.mla_tc0);
p->com.phase = 0;
/*
* initialize the output filter coeffs (i.e. multiply
* the coeffs with (1/(1-1/z)) to achieve integration
* this is now done in the filter parameter generation utility
*/
/*
* zero the filter
*/
for(fp1 = p->c.dec.output_filter, i = DEC_FILTERLEN; i > 0; i--)
*fp1++ = 0;
}
/* ---------------------------------------------------------------------- */
void cvsdstartwrite(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
float *fp1;
int i;
cvsdstartcommon(ft);
p->com.mla_tc1 = 0.1 * (1 - p->com.mla_tc0);
p->com.phase = 4;
/*
* zero the filter
*/
for(fp1 = p->c.enc.input_filter, i = ENC_FILTERLEN; i > 0; i--)
*fp1++ = 0;
p->c.enc.recon_int = 0;
}
/* ---------------------------------------------------------------------- */
void
cvsdstopwrite(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
if (p->bit.cnt) {
putc(p->bit.shreg, ft->fp);
p->bytes_written++;
}
report("cvsd: min slope %f, max slope %f\n",
p->com.v_min, p->com.v_max);
}
/* ---------------------------------------------------------------------- */
void
cvsdstopread(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
report("cvsd: min value %f, max value %f\n",
p->com.v_min, p->com.v_max);
}
/* ---------------------------------------------------------------------- */
#undef DEBUG
#ifdef DEBUG
static struct {
FILE *f1;
FILE *f2;
int cnt
} dbg = { NULL, NULL, 0 };
#endif
LONG cvsdread(ft, buf, nsamp)
ft_t ft;
LONG *buf, nsamp;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
int done = 0;
float oval;
#ifdef DEBUG
if (!dbg.f1) {
if (!(dbg.f1 = fopen("dbg1", "w")))
fail("debugging");
fprintf(dbg.f1, "\"input\"\n");
}
if (!dbg.f2) {
if (!(dbg.f2 = fopen("dbg2", "w")))
fail("debugging");
fprintf(dbg.f2, "\"recon\"\n");
}
#endif
while (done < nsamp) {
if (!p->bit.cnt) {
p->bit.shreg = getc(ft->fp);
if (feof(ft->fp))
return done;
p->bit.cnt = 8;
p->bit.mask = p->swapbits ? 0x80 : 1;
}
/*
* handle one bit
*/
p->bit.cnt--;
p->com.overload = ((p->com.overload << 1) |
(!!(p->bit.shreg & p->bit.mask))) & 7;
if (p->swapbits)
p->bit.mask >>= 1;
else
p->bit.mask <<= 1;
p->com.mla_int *= p->com.mla_tc0;
if ((p->com.overload == 0) || (p->com.overload == 7))
p->com.mla_int += p->com.mla_tc1;
memmove(p->c.dec.output_filter+1, p->c.dec.output_filter,
sizeof(p->c.dec.output_filter)-sizeof(float));
if (p->com.overload & 1)
p->c.dec.output_filter[0] = p->com.mla_int;
else
p->c.dec.output_filter[0] = -p->com.mla_int;
/*
* check if the next output is due
*/
p->com.phase += p->com.phase_inc;
if (p->com.phase >= 4) {
oval = float_conv(p->c.dec.output_filter,
(p->cvsd_rate < 24000) ?
dec_filter_16 : dec_filter_32,
DEC_FILTERLEN);
#ifdef DEBUG
fprintf(dbg.f1, "%f %f\n", (double)dbg.cnt,
(double)p->com.mla_int);
fprintf(dbg.f2, "%f %f\n", (double)dbg.cnt,
(double)oval);
dbg.cnt++;
#endif
if (oval > p->com.v_max)
p->com.v_max = oval;
if (oval < p->com.v_min)
p->com.v_min = oval;
*buf++ = (oval * ((float)LONG_MAX));
done++;
}
p->com.phase &= 3;
}
return done;
}
/* ---------------------------------------------------------------------- */
void
cvsdwrite(ft, buf, nsamp)
ft_t ft;
LONG *buf, nsamp;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
int done = 0;
float inval;
#ifdef DEBUG
if (!dbg.f1) {
if (!(dbg.f1 = fopen("dbg1", "w")))
fail("debugging");
fprintf(dbg.f1, "\"input\"\n");
}
if (!dbg.f2) {
if (!(dbg.f2 = fopen("dbg2", "w")))
fail("debugging");
fprintf(dbg.f2, "\"recon\"\n");
}
#endif
for(;;) {
/*
* check if the next input is due
*/
if (p->com.phase >= 4) {
if (done >= nsamp)
return;
memmove(p->c.enc.input_filter+1, p->c.enc.input_filter,
sizeof(p->c.enc.input_filter)-sizeof(float));
p->c.enc.input_filter[0] = (*buf++) /
((float)LONG_MAX);
done++;
}
p->com.phase &= 3;
/* insert input filter here! */
inval = float_conv(p->c.enc.input_filter,
(p->cvsd_rate < 24000) ?
(enc_filter_16[(p->com.phase >= 2)]) :
(enc_filter_32[p->com.phase]),
ENC_FILTERLEN);
/*
* encode one bit
*/
p->com.overload = (((p->com.overload << 1) |
(inval > p->c.enc.recon_int)) & 7);
p->com.mla_int *= p->com.mla_tc0;
if ((p->com.overload == 0) || (p->com.overload == 7))
p->com.mla_int += p->com.mla_tc1;
if (p->com.mla_int > p->com.v_max)
p->com.v_max = p->com.mla_int;
if (p->com.mla_int < p->com.v_min)
p->com.v_min = p->com.mla_int;
if (p->com.overload & 1) {
p->c.enc.recon_int += p->com.mla_int;
p->bit.shreg |= p->bit.mask;
} else
p->c.enc.recon_int -= p->com.mla_int;
if ((++(p->bit.cnt)) >= 8) {
putc(p->bit.shreg, ft->fp);
p->bytes_written++;
p->bit.shreg = p->bit.cnt = 0;
p->bit.mask = p->swapbits ? 0x80 : 1;
} else {
if (p->swapbits)
p->bit.mask >>= 1;
else
p->bit.mask <<= 1;
}
p->com.phase += p->com.phase_inc;
#ifdef DEBUG
fprintf(dbg.f1, "%f %f\n", (double)dbg.cnt, (double)inval);
fprintf(dbg.f2, "%f %f\n", (double)dbg.cnt,
(double)p->c.enc.recon_int);
dbg.cnt++;
#endif
}
}
/* ---------------------------------------------------------------------- */
/*
* DVMS file header
*/
struct dvms_header {
char Filename[14];
unsigned Id;
unsigned State;
time_t Unixtime;
unsigned Usender;
unsigned Ureceiver;
ULONG Length;
unsigned Srate;
unsigned Days;
unsigned Custom1;
unsigned Custom2;
char Info[16];
char extend[64];
unsigned Crc;
};
#define DVMS_HEADER_LEN 120
/* ---------------------------------------------------------------------- */
static ULONG get32(p)
unsigned char **p;
{
ULONG val = (((*p)[3]) << 24) | (((*p)[2]) << 16) |
(((*p)[1]) << 8) | (**p);
(*p) += 4;
return val;
}
static unsigned get16(p)
unsigned char **p;
{
unsigned val = (((*p)[1]) << 8) | (**p);
(*p) += 2;
return val;
}
static void put32(p, val)
unsigned char **p;
ULONG val;
{
*(*p)++ = val & 0xff;
*(*p)++ = (val >> 8) & 0xff;
*(*p)++ = (val >> 16) & 0xff;
*(*p)++ = (val >> 24) & 0xff;
}
static void put16(p, val)
unsigned char **p;
unsigned val;
{
*(*p)++ = val & 0xff;
*(*p)++ = (val >> 8) & 0xff;
}
/* ---------------------------------------------------------------------- */
static void dvms_read_header(f, hdr)
FILE *f;
struct dvms_header *hdr;
{
unsigned char hdrbuf[DVMS_HEADER_LEN];
unsigned char *pch = hdrbuf;
int i;
unsigned sum;
if (fread(hdrbuf, sizeof(hdrbuf), 1, f) != 1)
fail("unable to read DVMS header\n");
for(i = sizeof(hdrbuf), sum = 0; i > /*2*/3; i--) /* Deti bug */
sum += *pch++;
pch = hdrbuf;
memcpy(hdr->Filename, pch, sizeof(hdr->Filename));
pch += sizeof(hdr->Filename);
hdr->Id = get16(&pch);
hdr->State = get16(&pch);
hdr->Unixtime = get32(&pch);
hdr->Usender = get16(&pch);
hdr->Ureceiver = get16(&pch);
hdr->Length = get32(&pch);
hdr->Srate = get16(&pch);
hdr->Days = get16(&pch);
hdr->Custom1 = get16(&pch);
hdr->Custom2 = get16(&pch);
memcpy(hdr->Info, pch, sizeof(hdr->Info));
pch += sizeof(hdr->Info);
memcpy(hdr->extend, pch, sizeof(hdr->extend));
pch += sizeof(hdr->extend);
hdr->Crc = get16(&pch);
if (sum != hdr->Crc)
fail("DVMS header checksum error, read %u, calculated %u\n",
hdr->Crc, sum);
}
/* ---------------------------------------------------------------------- */
/*
* note! file must be seekable
*/
static void dvms_write_header(f, hdr)
FILE *f;
struct dvms_header *hdr;
{
unsigned char hdrbuf[DVMS_HEADER_LEN];
unsigned char *pch = hdrbuf;
unsigned char *pchs = hdrbuf;
int i;
unsigned sum;
memcpy(pch, hdr->Filename, sizeof(hdr->Filename));
pch += sizeof(hdr->Filename);
put16(&pch, hdr->Id);
put16(&pch, hdr->State);
put32(&pch, hdr->Unixtime);
put16(&pch, hdr->Usender);
put16(&pch, hdr->Ureceiver);
put32(&pch, hdr->Length);
put16(&pch, hdr->Srate);
put16(&pch, hdr->Days);
put16(&pch, hdr->Custom1);
put16(&pch, hdr->Custom2);
memcpy(pch, hdr->Info, sizeof(hdr->Info));
pch += sizeof(hdr->Info);
memcpy(pch, hdr->extend, sizeof(hdr->extend));
pch += sizeof(hdr->extend);
for(i = sizeof(hdrbuf), sum = 0; i > /*2*/3; i--) /* Deti bug */
sum += *pchs++;
hdr->Crc = sum;
put16(&pch, hdr->Crc);
if (fseek(f, 0, SEEK_SET) < 0)
fail("cannot write DVMS header, seek failed\n");
if (fwrite(hdrbuf, sizeof(hdrbuf), 1, f) != 1)
fail("cannot write DVMS header\n");
}
/* ---------------------------------------------------------------------- */
static void make_dvms_hdr(ft, hdr)
ft_t ft;
struct dvms_header *hdr;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
int len;
memset(hdr->Filename, 0, sizeof(hdr->Filename));
len = strlen(ft->filename);
if (len >= sizeof(hdr->Filename))
len = sizeof(hdr->Filename)-1;
memcpy(hdr->Filename, ft->filename, len);
hdr->Id = hdr->State = 0;
hdr->Unixtime = time(NULL);
hdr->Usender = hdr->Ureceiver = 0;
hdr->Length = p->bytes_written;
hdr->Srate = p->cvsd_rate/100;
hdr->Days = hdr->Custom1 = hdr->Custom2 = 0;
memset(hdr->Info, 0, sizeof(hdr->Info));
len = strlen(ft->comment);
if (len >= sizeof(hdr->Info))
len = sizeof(hdr->Info)-1;
memcpy(hdr->Info, ft->comment, len);
memset(hdr->extend, 0, sizeof(hdr->extend));
}
/* ---------------------------------------------------------------------- */
void dvmsstartread(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
struct dvms_header hdr;
dvms_read_header(ft->fp, &hdr);
report("DVMS header of source file \"%s\":");
report(" filename \"%.14s\"",ft->filename);
report(" id 0x%x", hdr.Filename);
report(" state 0x%x", hdr.Id, hdr.State);
report(" time %s",ctime(&hdr.Unixtime)); /* ctime generates lf */
report(" usender %u", hdr.Usender);
report(" ureceiver %u", hdr.Ureceiver);
report(" length %u", hdr.Length);
report(" srate %u", hdr.Srate);
report(" days %u", hdr.Days);
report(" custom1 %u", hdr.Custom1);
report(" custom2 %u", hdr.Custom2);
report(" info \"%.16s\"\n", hdr.Info);
ft->info.rate = (hdr.Srate < 240) ? 16000 : 32000;
report("DVMS rate %dbit/s using %dbit/s deviation %d%%\n",
hdr.Srate*100, ft->info.rate,
((ft->info.rate - hdr.Srate*100) * 100) / ft->info.rate);
cvsdstartread(ft);
p->swapbits = 0;
}
/* ---------------------------------------------------------------------- */
void dvmsstartwrite(ft)
ft_t ft;
{
struct cvsdpriv *p = (struct cvsdpriv *) ft->priv;
struct dvms_header hdr;
cvsdstartwrite(ft);
make_dvms_hdr(ft, &hdr);
dvms_write_header(ft->fp, &hdr);
if (!ft->seekable)
warn("Length in output .DVMS header will wrong since can't seek to fix it");
p->swapbits = 0;
}
/* ---------------------------------------------------------------------- */
void
dvmsstopwrite(ft)
ft_t ft;
{
struct dvms_header hdr;
cvsdstopwrite(ft);
if (!ft->seekable)
return;
if (fseek(ft->fp, 0L, 0) != 0)
fail("Can't rewind output file to rewrite DVMS header.");
make_dvms_hdr(ft, &hdr);
dvms_write_header(ft->fp, &hdr);
}
/* ---------------------------------------------------------------------- */