ref: c2fda8f3e4f3623d1766d37078fb05d3ef6dbbe8
dir: /src/cvsd.c/
/* libSoX 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 library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library 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 Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Change History:
*
* June 1, 1998 - Chris Bagwell (cbagwell@sprynet.com)
* Fixed compile warnings reported by Kjetil Torgrim Homme
* <kjetilho@ifi.uio.no>
*
* June 20, 2006 - Kimberly Rockwell (pyxis13317 (at) yahoo.com)
* Speed optimization: Unrolled float_conv() loop in seperate
* functions for encoding and decoding. 15% speed up decoding.
*
* Aug. 24, 2009 - P. Chaintreuil (sox-cvsd-peep (at) parallaxshift.com)
* Speed optimization: Replaced calls to memmove() with a
* mirrored circular buffer. This doubles the size of the
* dec.output_filter (48 -> 96 floats) and enc.input_filter
* (16 -> 32 floats), but keeps the memory from having to
* be copied so many times. 56% speed increase decoding;
* less than 5% encoding speed increase.
*/
#include "sox_i.h"
#include "cvsd.h"
#include "cvsdfilt.h"
#include <string.h>
#include <time.h>
/* ---------------------------------------------------------------------- */
/*
* private data structures
*/
typedef cvsd_priv_t priv_t;
static int debug_count = 0;
/* ---------------------------------------------------------------------- */
/* This float_conv() function is not used as more specialized/optimized
* versions exist below. However, those new versions are tied to
* very percise filters defined in cvsdfilt.h. If those are modified
* or different filters are found to be required, this function may
* be needed. Thus I leave it here for possible future use, but commented
* out to avoid compiler warnings about it not being used.
static float float_conv(float const *fp1, float const *fp2,int n)
{
float res = 0;
for(; n > 0; n--)
res += (*fp1++) * (*fp2++);
return res;
}
*/
static float float_conv_enc(float const *fp1, float const *fp2)
{
/* This is a specialzed version of float_conv() for encoding
* which simply assumes a CVSD_ENC_FILTERLEN (16) length of
* the two arrays and unrolls that loop.
*
* fp1 should be the enc.input_filter array and must be
* CVSD_ENC_FILTERLEN (16) long.
*
* fp2 should be one of the enc_filter_xx_y() tables listed
* in cvsdfilt.h. At minimum, fp2 must be CVSD_ENC_FILTERLEN
* (16) entries long.
*/
float res = 0;
/* unrolling loop */
res += fp1[0] * fp2[0];
res += fp1[1] * fp2[1];
res += fp1[2] * fp2[2];
res += fp1[3] * fp2[3];
res += fp1[4] * fp2[4];
res += fp1[5] * fp2[5];
res += fp1[6] * fp2[6];
res += fp1[7] * fp2[7];
res += fp1[8] * fp2[8];
res += fp1[9] * fp2[9];
res += fp1[10] * fp2[10];
res += fp1[11] * fp2[11];
res += fp1[12] * fp2[12];
res += fp1[13] * fp2[13];
res += fp1[14] * fp2[14];
res += fp1[15] * fp2[15];
return res;
}
static float float_conv_dec(float const *fp1, float const *fp2)
{
/* This is a specialzed version of float_conv() for decoding
* which assumes a specific length and structure to the data
* in fp2.
*
* fp1 should be the dec.output_filter array and must be
* CVSD_DEC_FILTERLEN (48) long.
*
* fp2 should be one of the dec_filter_xx() tables listed
* in cvsdfilt.h. fp2 is assumed to be CVSD_DEC_FILTERLEN
* (48) entries long, is assumed to have 0.0 in the last
* entry, and is a symmetrical mirror around fp2[23] (ie,
* fp2[22] == fp2[24], fp2[0] == fp2[47], etc).
*/
float res = 0;
/* unrolling loop, also taking advantage of the symmetry
* of the sampling rate array*/
res += (fp1[0] + fp1[46]) * fp2[0];
res += (fp1[1] + fp1[45]) * fp2[1];
res += (fp1[2] + fp1[44]) * fp2[2];
res += (fp1[3] + fp1[43]) * fp2[3];
res += (fp1[4] + fp1[42]) * fp2[4];
res += (fp1[5] + fp1[41]) * fp2[5];
res += (fp1[6] + fp1[40]) * fp2[6];
res += (fp1[7] + fp1[39]) * fp2[7];
res += (fp1[8] + fp1[38]) * fp2[8];
res += (fp1[9] + fp1[37]) * fp2[9];
res += (fp1[10] + fp1[36]) * fp2[10];
res += (fp1[11] + fp1[35]) * fp2[11];
res += (fp1[12] + fp1[34]) * fp2[12];
res += (fp1[13] + fp1[33]) * fp2[13];
res += (fp1[14] + fp1[32]) * fp2[14];
res += (fp1[15] + fp1[31]) * fp2[15];
res += (fp1[16] + fp1[30]) * fp2[16];
res += (fp1[17] + fp1[29]) * fp2[17];
res += (fp1[18] + fp1[28]) * fp2[18];
res += (fp1[19] + fp1[27]) * fp2[19];
res += (fp1[20] + fp1[26]) * fp2[20];
res += (fp1[21] + fp1[25]) * fp2[21];
res += (fp1[22] + fp1[24]) * fp2[22];
res += (fp1[23]) * fp2[23];
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(sox_format_t * ft)
{
priv_t *p = (priv_t *) ft->priv;
p->cvsd_rate = (ft->signal.rate <= 24000) ? 16000 : 32000;
ft->signal.rate = 8000;
ft->signal.channels = 1;
lsx_rawstart(ft, sox_true, sox_false, sox_true, SOX_ENCODING_CVSD, 1);
/*
* 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 = 1;
/*
* count the bytes written
*/
p->bytes_written = 0;
p->com.v_min = 1;
p->com.v_max = -1;
lsx_report("cvsd: bit rate %dbit/s, bits from %s", p->cvsd_rate,
ft->encoding.reverse_bits ? "msb to lsb" : "lsb to msb");
}
/* ---------------------------------------------------------------------- */
int lsx_cvsdstartread(sox_format_t * ft)
{
priv_t *p = (priv_t *) 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 = CVSD_DEC_FILTERLEN*2; i > 0; i--)
*fp1++ = 0;
/* initialize mirror circular buffer offset to anything sane. */
p->c.dec.offset = CVSD_DEC_FILTERLEN - 1;
return (SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
int lsx_cvsdstartwrite(sox_format_t * ft)
{
priv_t *p = (priv_t *) 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 = CVSD_ENC_FILTERLEN*2; i > 0; i--)
*fp1++ = 0;
p->c.enc.recon_int = 0;
/* initialize mirror circular buffer offset to anything sane. */
p->c.enc.offset = CVSD_ENC_FILTERLEN - 1;
return(SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
int lsx_cvsdstopwrite(sox_format_t * ft)
{
priv_t *p = (priv_t *) ft->priv;
if (p->bit.cnt) {
lsx_writeb(ft, p->bit.shreg);
p->bytes_written++;
}
lsx_debug("cvsd: min slope %f, max slope %f",
p->com.v_min, p->com.v_max);
return (SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
int lsx_cvsdstopread(sox_format_t * ft)
{
priv_t *p = (priv_t *) ft->priv;
lsx_debug("cvsd: min value %f, max value %f",
p->com.v_min, p->com.v_max);
return(SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
size_t lsx_cvsdread(sox_format_t * ft, sox_sample_t *buf, size_t nsamp)
{
priv_t *p = (priv_t *) ft->priv;
size_t done = 0;
float oval;
while (done < nsamp) {
if (!p->bit.cnt) {
if (lsx_read_b_buf(ft, &(p->bit.shreg), (size_t) 1) != 1)
return done;
p->bit.cnt = 8;
p->bit.mask = 1;
}
/*
* handle one bit
*/
p->bit.cnt--;
p->com.overload = ((p->com.overload << 1) |
(!!(p->bit.shreg & p->bit.mask))) & 7;
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;
/* shift output filter window in mirror cirular buffer. */
if (p->c.dec.offset != 0)
--p->c.dec.offset;
else p->c.dec.offset = CVSD_DEC_FILTERLEN - 1;
/* write into both halves of the mirror circular buffer */
if (p->com.overload & 1)
{
p->c.dec.output_filter[p->c.dec.offset] = p->com.mla_int;
p->c.dec.output_filter[p->c.dec.offset + CVSD_DEC_FILTERLEN] = p->com.mla_int;
}
else
{
p->c.dec.output_filter[p->c.dec.offset] = -p->com.mla_int;
p->c.dec.output_filter[p->c.dec.offset + CVSD_DEC_FILTERLEN] = -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_dec(
p->c.dec.output_filter + p->c.dec.offset,
(p->cvsd_rate < 24000) ?
dec_filter_16 : dec_filter_32);
lsx_debug_more("input %d %f\n", debug_count, p->com.mla_int);
lsx_debug_more("recon %d %f\n", debug_count, oval);
debug_count++;
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)SOX_SAMPLE_MAX));
done++;
}
p->com.phase &= 3;
}
return done;
}
/* ---------------------------------------------------------------------- */
size_t lsx_cvsdwrite(sox_format_t * ft, const sox_sample_t *buf, size_t nsamp)
{
priv_t *p = (priv_t *) ft->priv;
size_t done = 0;
float inval;
for(;;) {
/*
* check if the next input is due
*/
if (p->com.phase >= 4) {
if (done >= nsamp)
return done;
/* shift input filter window in mirror cirular buffer. */
if (p->c.enc.offset != 0)
--p->c.enc.offset;
else p->c.enc.offset = CVSD_ENC_FILTERLEN - 1;
/* write into both halves of the mirror circular buffer */
p->c.enc.input_filter[p->c.enc.offset] =
p->c.enc.input_filter[p->c.enc.offset
+ CVSD_ENC_FILTERLEN] =
(*buf++) /
((float)SOX_SAMPLE_MAX);
done++;
}
p->com.phase &= 3;
/* insert input filter here! */
inval = float_conv_enc(
p->c.enc.input_filter + p->c.enc.offset,
(p->cvsd_rate < 24000) ?
(enc_filter_16[(p->com.phase >= 2)]) :
(enc_filter_32[p->com.phase]));
/*
* 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) {
lsx_writeb(ft, p->bit.shreg);
p->bytes_written++;
p->bit.shreg = p->bit.cnt = 0;
p->bit.mask = 1;
} else
p->bit.mask <<= 1;
p->com.phase += p->com.phase_inc;
lsx_debug_more("input %d %f\n", debug_count, inval);
lsx_debug_more("recon %d %f\n", debug_count, p->c.enc.recon_int);
debug_count++;
}
}
/* ---------------------------------------------------------------------- */
/*
* DVMS file header
*/
/* FIXME: eliminate these 4 functions */
static uint32_t get32_le(unsigned char **p)
{
uint32_t val = (((*p)[3]) << 24) | (((*p)[2]) << 16) |
(((*p)[1]) << 8) | (**p);
(*p) += 4;
return val;
}
static uint16_t get16_le(unsigned char **p)
{
unsigned val = (((*p)[1]) << 8) | (**p);
(*p) += 2;
return val;
}
static void put32_le(unsigned char **p, uint32_t val)
{
*(*p)++ = val & 0xff;
*(*p)++ = (val >> 8) & 0xff;
*(*p)++ = (val >> 16) & 0xff;
*(*p)++ = (val >> 24) & 0xff;
}
static void put16_le(unsigned char **p, unsigned val)
{
*(*p)++ = val & 0xff;
*(*p)++ = (val >> 8) & 0xff;
}
struct dvms_header {
char Filename[14];
unsigned Id;
unsigned State;
time_t Unixtime;
unsigned Usender;
unsigned Ureceiver;
size_t Length;
unsigned Srate;
unsigned Days;
unsigned Custom1;
unsigned Custom2;
char Info[16];
char extend[64];
unsigned Crc;
};
#define DVMS_HEADER_LEN 120
/* ---------------------------------------------------------------------- */
static int dvms_read_header(sox_format_t * ft, struct dvms_header *hdr)
{
unsigned char hdrbuf[DVMS_HEADER_LEN];
unsigned char *pch = hdrbuf;
int i;
unsigned sum;
if (lsx_readbuf(ft, hdrbuf, sizeof(hdrbuf)) != sizeof(hdrbuf))
{
return (SOX_EOF);
}
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_le(&pch);
hdr->State = get16_le(&pch);
hdr->Unixtime = get32_le(&pch);
hdr->Usender = get16_le(&pch);
hdr->Ureceiver = get16_le(&pch);
hdr->Length = get32_le(&pch);
hdr->Srate = get16_le(&pch);
hdr->Days = get16_le(&pch);
hdr->Custom1 = get16_le(&pch);
hdr->Custom2 = get16_le(&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_le(&pch);
if (sum != hdr->Crc)
{
lsx_report("DVMS header checksum error, read %u, calculated %u",
hdr->Crc, sum);
return (SOX_EOF);
}
return (SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
/*
* note! file must be seekable
*/
static int dvms_write_header(sox_format_t * ft, 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_le(&pch, hdr->Id);
put16_le(&pch, hdr->State);
put32_le(&pch, (unsigned)hdr->Unixtime);
put16_le(&pch, hdr->Usender);
put16_le(&pch, hdr->Ureceiver);
put32_le(&pch, (unsigned) hdr->Length);
put16_le(&pch, hdr->Srate);
put16_le(&pch, hdr->Days);
put16_le(&pch, hdr->Custom1);
put16_le(&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_le(&pch, hdr->Crc);
if (lsx_seeki(ft, (off_t)0, SEEK_SET) < 0)
{
lsx_report("seek failed\n: %s",strerror(errno));
return (SOX_EOF);
}
if (lsx_writebuf(ft, hdrbuf, sizeof(hdrbuf)) != sizeof(hdrbuf))
{
lsx_report("%s",strerror(errno));
return (SOX_EOF);
}
return (SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
static void make_dvms_hdr(sox_format_t * ft, struct dvms_header *hdr)
{
priv_t *p = (priv_t *) ft->priv;
size_t len;
char * comment = lsx_cat_comments(ft->oob.comments);
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 = sox_globals.repeatable? 0 : 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(comment);
if (len >= sizeof(hdr->Info))
len = sizeof(hdr->Info)-1;
memcpy(hdr->Info, comment, len);
memset(hdr->extend, 0, sizeof(hdr->extend));
free(comment);
}
/* ---------------------------------------------------------------------- */
int lsx_dvmsstartread(sox_format_t * ft)
{
struct dvms_header hdr;
int rc;
rc = dvms_read_header(ft, &hdr);
if (rc){
lsx_fail_errno(ft,SOX_EHDR,"unable to read DVMS header");
return rc;
}
lsx_debug("DVMS header of source file \"%s\":", ft->filename);
lsx_debug(" filename \"%.14s\"", hdr.Filename);
lsx_debug(" id 0x%x", hdr.Id);
lsx_debug(" state 0x%x", hdr.State);
lsx_debug(" time %s", ctime(&hdr.Unixtime)); /* ctime generates lf */
lsx_debug(" usender %u", hdr.Usender);
lsx_debug(" ureceiver %u", hdr.Ureceiver);
lsx_debug(" length %" PRIuPTR, hdr.Length);
lsx_debug(" srate %u", hdr.Srate);
lsx_debug(" days %u", hdr.Days);
lsx_debug(" custom1 %u", hdr.Custom1);
lsx_debug(" custom2 %u", hdr.Custom2);
lsx_debug(" info \"%.16s\"", hdr.Info);
ft->signal.rate = (hdr.Srate < 240) ? 16000 : 32000;
lsx_debug("DVMS rate %dbit/s using %gbit/s deviation %g%%",
hdr.Srate*100, ft->signal.rate,
((ft->signal.rate - hdr.Srate*100) * 100) / ft->signal.rate);
rc = lsx_cvsdstartread(ft);
if (rc)
return rc;
return(SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
int lsx_dvmsstartwrite(sox_format_t * ft)
{
struct dvms_header hdr;
int rc;
rc = lsx_cvsdstartwrite(ft);
if (rc)
return rc;
make_dvms_hdr(ft, &hdr);
rc = dvms_write_header(ft, &hdr);
if (rc){
lsx_fail_errno(ft,rc,"cannot write DVMS header");
return rc;
}
if (!ft->seekable)
lsx_warn("Length in output .DVMS header will wrong since can't seek to fix it");
return(SOX_SUCCESS);
}
/* ---------------------------------------------------------------------- */
int lsx_dvmsstopwrite(sox_format_t * ft)
{
struct dvms_header hdr;
int rc;
lsx_cvsdstopwrite(ft);
if (!ft->seekable)
{
lsx_warn("File not seekable");
return (SOX_EOF);
}
if (lsx_seeki(ft, (off_t)0, 0) != 0)
{
lsx_fail_errno(ft,errno,"Can't rewind output file to rewrite DVMS header.");
return(SOX_EOF);
}
make_dvms_hdr(ft, &hdr);
rc = dvms_write_header(ft, &hdr);
if(rc){
lsx_fail_errno(ft,rc,"cannot write DVMS header");
return rc;
}
return rc;
}