c022bb8d51
Remove ENABLE_IAX option Add an improved FGCom standalone as part of FG in utils directory
159 lines
3.1 KiB
C
159 lines
3.1 KiB
C
/*
|
|
* iaxclient: a cross-platform IAX softphone library
|
|
*
|
|
* Copyrights:
|
|
* Copyright (C) 2004 Cyril VELTER
|
|
*
|
|
* Contributors:
|
|
* Cyril VELTER <cyril.velter@metadys.com>
|
|
*
|
|
* This program is free software, distributed under the terms of
|
|
* the GNU Lesser (Library) General Public License.
|
|
*/
|
|
|
|
#include "codec_alaw.h"
|
|
#include "iaxclient_lib.h"
|
|
|
|
#if defined(_MSC_VER)
|
|
#define INLINE __inline
|
|
#else
|
|
#define INLINE inline
|
|
#endif
|
|
|
|
struct state {
|
|
plc_state_t plc;
|
|
};
|
|
|
|
static INLINE short int alawdecode (unsigned char alaw)
|
|
{
|
|
int value;
|
|
int segment;
|
|
|
|
/* Mask value */
|
|
alaw ^= 0x55;
|
|
|
|
/* Extract and scale value */
|
|
value = (alaw & 0x0f) << 4;
|
|
|
|
/* Extract segment number */
|
|
segment = (alaw & 0x70) >> 4;
|
|
|
|
/* Compute value */
|
|
switch (segment) {
|
|
case 0:
|
|
break;
|
|
case 1:
|
|
value += 0x100;
|
|
break;
|
|
default:
|
|
value += 0x100;
|
|
value <<= segment - 1;
|
|
}
|
|
|
|
/* Extract sign */
|
|
return (alaw & 0x80) ? value : -value;
|
|
}
|
|
|
|
static INLINE unsigned char alawencode (short int linear)
|
|
{
|
|
int mask = 0x55;
|
|
int segment;
|
|
unsigned char alaw;
|
|
|
|
static int segments[8] = {0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
|
|
|
|
if (linear >= 0)
|
|
{
|
|
/* Sign (7th) bit = 1 */
|
|
mask |= 0x80;
|
|
}
|
|
else
|
|
{
|
|
/* Sign (7th) bit = 0 */
|
|
linear = -linear;
|
|
}
|
|
|
|
/* Find the segment */
|
|
for (segment = 0;segment < 8;segment++)
|
|
if (linear <= segments[segment])
|
|
break;
|
|
|
|
/* Combine the sign, segment, and quantization bits. */
|
|
|
|
if (segment < 8)
|
|
{
|
|
if (segment < 2)
|
|
alaw = (linear >> 4) & 0x0F;
|
|
else
|
|
alaw = (linear >> (segment + 3)) & 0x0F;
|
|
|
|
return ((alaw | (segment << 4)) ^ mask);
|
|
}
|
|
else
|
|
/* out of range, return maximum value. */
|
|
return (0x7F ^ mask);
|
|
}
|
|
|
|
static int decode ( struct iaxc_audio_codec *c,
|
|
int *inlen, unsigned char *in, int *outlen, short *out ) {
|
|
struct state *state = (struct state *)(c->decstate);
|
|
short *orig_out = out;
|
|
short sample;
|
|
|
|
|
|
if(*inlen == 0) {
|
|
int interp_len = 160;
|
|
if(*outlen < interp_len) interp_len = *outlen;
|
|
plc_fillin(&state->plc,out,interp_len);
|
|
*outlen -= interp_len;
|
|
return 0;
|
|
}
|
|
|
|
|
|
while ((*inlen > 0) && (*outlen > 0)) {
|
|
sample = alawdecode((unsigned char)*(in++));
|
|
*(out++) = sample;
|
|
(*inlen)--; (*outlen)--;
|
|
}
|
|
plc_rx(&state->plc, orig_out, (int)(out - orig_out));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int encode ( struct iaxc_audio_codec *c,
|
|
int *inlen, short *in, int *outlen, unsigned char *out ) {
|
|
|
|
while ((*inlen > 0) && (*outlen > 0)) {
|
|
*(out++) = alawencode(*(in++));
|
|
(*inlen)--; (*outlen)--;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void destroy ( struct iaxc_audio_codec *c) {
|
|
free(c);
|
|
}
|
|
|
|
struct iaxc_audio_codec *codec_audio_alaw_new() {
|
|
|
|
struct iaxc_audio_codec *c = (struct iaxc_audio_codec *)calloc(1, sizeof(struct iaxc_audio_codec));
|
|
|
|
if(!c) return c;
|
|
|
|
strcpy(c->name,"alaw");
|
|
c->format = IAXC_FORMAT_ALAW;
|
|
c->encode = encode;
|
|
c->decode = decode;
|
|
c->destroy = destroy;
|
|
|
|
/* really, we can use less, but don't want to */
|
|
c->minimum_frame_size = 160;
|
|
|
|
/* decoder state, used for interpolation */
|
|
c->decstate = calloc(sizeof(struct state),1);
|
|
plc_init(&((struct state *)c->decstate)->plc);
|
|
|
|
return c;
|
|
}
|
|
|