ref: d198b7490bcdaa714c43bf5852d89c6ceba33aa6
dir: /src/gsm.c/
/* Copyright 1991, 1992, 1993 Guido van Rossum And Sundry Contributors.
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Guido van Rossum And Sundry Contributors are not responsible for
* the consequences of using this software.
*/
/*
* GSM 06.10 courtesy Communications and Operating Systems Research Group,
* Technische Universitaet Berlin
*
* More information on this format can be obtained from
* http://www.cs.tu-berlin.de/~jutta/toasox.html
*
* Source is available from ftp://ftp.cs.tu-berlin.de/pub/local/kbs/tubmik/gsm
*
* Written 26 Jan 1995 by Andrew Pam
* Portions Copyright (c) 1995 Serious Cybernetics
*
* July 19, 1998 - Chris Bagwell (cbagwell@sprynet.com)
* Added GSM support to SOX from patches floating around with the help
* of Dima Barsky (ess2db@ee.surrey.ac.uk).
*
* Nov. 26, 1999 - Stan Brooks (stabro@megsinet.com)
* Rewritten to support multiple channels
*/
#include "sox_i.h"
#ifdef EXTERNAL_GSM
#ifdef HAVE_GSM_GSM_H
#include <gsm/gsm.h>
#else
#include <gsm.h>
#endif
#else
#include "../libgsm/gsm.h"
#endif
#include <errno.h>
#define MAXCHANS 16
/* sizeof(gsm_frame) */
#define FRAMESIZE (size_t)33
/* samples per gsm_frame */
#define BLOCKSIZE 160
/* Private data */
typedef struct {
unsigned channels;
gsm_signal *samples;
gsm_signal *samplePtr;
gsm_signal *sampleTop;
gsm_byte *frames;
gsm handle[MAXCHANS];
} priv_t;
static int gsmstart_rw(sox_format_t * ft, int w)
{
priv_t *p = (priv_t *) ft->priv;
unsigned ch;
ft->encoding.encoding = SOX_ENCODING_GSM;
if (!ft->signal.rate)
ft->signal.rate = 8000;
if (ft->signal.channels == 0)
ft->signal.channels = 1;
p->channels = ft->signal.channels;
if (p->channels > MAXCHANS || p->channels <= 0)
{
lsx_fail_errno(ft,SOX_EFMT,"gsm: channels(%d) must be in 1-16", ft->signal.channels);
return(SOX_EOF);
}
for (ch=0; ch<p->channels; ch++) {
p->handle[ch] = gsm_create();
if (!p->handle[ch])
{
lsx_fail_errno(ft,errno,"unable to create GSM stream");
return (SOX_EOF);
}
}
p->frames = lsx_malloc(p->channels*FRAMESIZE);
p->samples = lsx_malloc(BLOCKSIZE * (p->channels+1) * sizeof(gsm_signal));
p->sampleTop = p->samples + BLOCKSIZE*p->channels;
p->samplePtr = (w)? p->samples : p->sampleTop;
return (SOX_SUCCESS);
}
static int sox_gsmstartread(sox_format_t * ft)
{
return gsmstart_rw(ft,0);
}
static int sox_gsmstartwrite(sox_format_t * ft)
{
return gsmstart_rw(ft,1);
}
/*
* Read up to len samples from file.
* Convert to signed longs.
* Place in buf[].
* Return number of samples read.
*/
static size_t sox_gsmread(sox_format_t * ft, sox_sample_t *buf, size_t samp)
{
size_t done = 0, r;
int ch, chans;
gsm_signal *gbuff;
priv_t *p = (priv_t *) ft->priv;
chans = p->channels;
while (done < samp)
{
while (p->samplePtr < p->sampleTop && done < samp)
buf[done++] =
SOX_SIGNED_16BIT_TO_SAMPLE(*(p->samplePtr)++,);
if (done>=samp) break;
r = lsx_readbuf(ft, p->frames, p->channels * FRAMESIZE);
if (r != p->channels * FRAMESIZE)
break;
p->samplePtr = p->samples;
for (ch=0; ch<chans; ch++) {
int i;
gsm_signal *gsp;
gbuff = p->sampleTop;
if (gsm_decode(p->handle[ch], p->frames + ch*FRAMESIZE, gbuff) < 0)
{
lsx_fail_errno(ft,errno,"error during GSM decode");
return (0);
}
gsp = p->samples + ch;
for (i=0; i<BLOCKSIZE; i++) {
*gsp = *gbuff++;
gsp += chans;
}
}
}
return done;
}
static int gsmflush(sox_format_t * ft)
{
int r, ch, chans;
gsm_signal *gbuff;
priv_t *p = (priv_t *) ft->priv;
chans = p->channels;
/* zero-fill samples as needed */
while (p->samplePtr < p->sampleTop)
*(p->samplePtr)++ = 0;
gbuff = p->sampleTop;
for (ch=0; ch<chans; ch++) {
int i;
gsm_signal *gsp;
gsp = p->samples + ch;
for (i=0; i<BLOCKSIZE; i++) {
gbuff[i] = *gsp;
gsp += chans;
}
gsm_encode(p->handle[ch], gbuff, p->frames);
r = lsx_writebuf(ft, p->frames, FRAMESIZE);
if (r != FRAMESIZE)
{
lsx_fail_errno(ft,errno,"write error");
return(SOX_EOF);
}
}
p->samplePtr = p->samples;
return (SOX_SUCCESS);
}
static size_t sox_gsmwrite(sox_format_t * ft, const sox_sample_t *buf, size_t samp)
{
size_t done = 0;
priv_t *p = (priv_t *) ft->priv;
while (done < samp)
{
while ((p->samplePtr < p->sampleTop) && (done < samp))
*(p->samplePtr)++ =
SOX_SAMPLE_TO_SIGNED_16BIT(buf[done++], ft->clips);
if (p->samplePtr == p->sampleTop)
{
if(gsmflush(ft))
{
return 0;
}
}
}
return done;
}
static int sox_gsmstopread(sox_format_t * ft)
{
priv_t *p = (priv_t *) ft->priv;
unsigned ch;
for (ch=0; ch<p->channels; ch++)
gsm_destroy(p->handle[ch]);
free(p->samples);
free(p->frames);
return (SOX_SUCCESS);
}
static int sox_gsmstopwrite(sox_format_t * ft)
{
int rc;
priv_t *p = (priv_t *) ft->priv;
if (p->samplePtr > p->samples)
{
rc = gsmflush(ft);
if (rc)
return rc;
}
return sox_gsmstopread(ft); /* destroy handles and free buffers */
}
SOX_FORMAT_HANDLER(gsm)
{
static char const * const names[] = {"gsm", NULL};
static sox_rate_t const write_rates[] = {8000, 0};
static unsigned const write_encodings[] = {SOX_ENCODING_GSM, 0, 0};
static sox_format_handler_t handler = {SOX_LIB_VERSION_CODE,
"GSM 06.10 (full-rate) lossy speech compression", names, 0,
sox_gsmstartread, sox_gsmread, sox_gsmstopread,
sox_gsmstartwrite, sox_gsmwrite, sox_gsmstopwrite,
NULL, write_encodings, write_rates, sizeof(priv_t)
};
return &handler;
}