/*
* g723_40_decoder()
*
* Decodes a 5-bit CCITT G.723 40Kbps code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
* -1 is returned if the output coding is unknown.
*/
int g723_40_decoder (int i, G72x_STATE *state_ptr)
{
short sezi, sei, sez, se; /* ACCUM */
short y ; /* MIX */
short sr; /* ADDB */
short dq;
short dqsez;
i &= 0x1f; /* mask to get proper bits */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
sei = sezi + predictor_pole(state_ptr);
se = sei >> 1; /* se = estimated signal */
y = step_size(state_ptr); /* adaptive quantizer step size */
dq = reconstruct(i & 0x10, _dqlntab[i], y); /* estimation diff. */
sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); /* reconst. signal */
dqsez = sr - se + sez; /* pole prediction diff. */
update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
return (sr << 2); /* sr was of 14-bit dynamic range */
}
/*
* g723_40_encoder()
*
* Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens
* the resulting 5-bit CCITT G.723 40Kbps code.
* Returns -1 if the input coding value is invalid.
*/
int g723_40_encoder (int sl, G72x_STATE *state_ptr)
{
short sei, sezi, se, sez; /* ACCUM */
short d; /* SUBTA */
short y; /* MIX */
short sr; /* ADDB */
short dqsez; /* ADDC */
short dq, i;
/* linearize input sample to 14-bit PCM */
sl >>= 2; /* sl of 14-bit dynamic range */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
sei = sezi + predictor_pole(state_ptr);
se = sei >> 1; /* se = estimated signal */
d = sl - se; /* d = estimation difference */
/* quantize prediction difference */
y = step_size(state_ptr); /* adaptive quantizer step size */
i = quantize(d, y, qtab_723_40, 15); /* i = ADPCM code */
dq = reconstruct(i & 0x10, _dqlntab[i], y); /* quantized diff */
sr = (dq < 0) ? se - (dq & 0x7FFF) : se + dq; /* reconstructed signal */
dqsez = sr + sez - se; /* dqsez = pole prediction diff. */
update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
return (i);
}
/*
* g721_encoder()
*
* Encodes the input vale of linear PCM, A-law or u-law data sl and returns
* the resulting code. -1 is returned for unknown input coding value.
*/
int
g721_encoder(
int sl,
G72x_STATE *state_ptr)
{
short sezi, se, sez; /* ACCUM */
short d; /* SUBTA */
short sr; /* ADDB */
short y; /* MIX */
short dqsez; /* ADDC */
short dq, i;
/* linearize input sample to 14-bit PCM */
sl >>= 2; /* 14-bit dynamic range */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
se = (sezi + predictor_pole(state_ptr)) >> 1; /* estimated signal */
d = sl - se; /* estimation difference */
/* quantize the prediction difference */
y = step_size(state_ptr); /* quantizer step size */
i = quantize(d, y, qtab_721, 7); /* i = ADPCM code */
dq = reconstruct(i & 8, _dqlntab[i], y); /* quantized est diff */
sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconst. signal */
dqsez = sr + sez - se; /* pole prediction diff. */
update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
return (i);
}
/*
* g726_32_decoder()
*
* Description:
*
* Decodes a 4-bit code of G.726_32 encoded data of i and
* returns the resulting linear PCM, A-law or u-law value.
* return -1 for unknown out_coding value.
*/
int
g726_32_decoder(
int i,
int out_coding,
struct g726_state *state_ptr)
{
short sezi, sei, sez, se; /* ACCUM */
short y; /* MIX */
short sr; /* ADDB */
short dq;
short dqsez;
i &= 0x0f; /* mask to get proper bits */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
sei = sezi + predictor_pole(state_ptr);
se = sei >> 1; /* se = estimated signal */
y = step_size(state_ptr); /* dynamic quantizer step size */
dq = reconstruct(i & 0x08, _dqlntab[i], y); /* quantized diff. */
sr = (dq < 0) ? (se - (dq & 0x3FFF)) : se + dq; /* reconst. signal */
dqsez = sr - se + sez; /* pole prediction diff. */
update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
switch (out_coding) {
case AUDIO_ENCODING_LINEAR:
return (sr << 2); /* sr was 14-bit dynamic range */
default:
return (-1);
}
}
/*
* g723_24_decoder()
*
* Decodes a 3-bit CCITT G.723_24 ADPCM code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
* -1 is returned if the output coding is unknown.
*/
int
g726_24_decoder(
int i,
g726_state *state_ptr)
{
int sezi;
int sez; /* ACCUM */
int sei;
int se;
int y; /* MIX */
int dq;
int sr; /* ADDB */
int dqsez;
i &= 0x07; /* mask to get proper bits */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
sei = sezi + predictor_pole(state_ptr);
se = sei >> 1; /* se = estimated signal */
y = step_size(state_ptr); /* adaptive quantizer step size */
dq = reconstruct(i & 0x04, _dqlntab[i], y); /* unquantize pred diff */
sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); /* reconst. signal */
dqsez = sr - se + sez; /* pole prediction diff. */
update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
return (sr << 2); /* sr was of 14-bit dynamic range */
}
/*
* g723_16_encoder()
*
* Encodes a linear PCM, A-law or u-law input sample and returns its 2-bit code.
* Returns -1 if invalid input coding value.
*/
int
g723_16_encoder(
int sl,
G72x_STATE *state_ptr)
{
short sei, sezi, se, sez; /* ACCUM */
short d; /* SUBTA */
short y; /* MIX */
short sr; /* ADDB */
short dqsez; /* ADDC */
short dq, i;
/* linearize input sample to 14-bit PCM */
sl >>= 2; /* sl of 14-bit dynamic range */
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
sei = sezi + predictor_pole(state_ptr);
se = sei >> 1; /* se = estimated signal */
d = sl - se; /* d = estimation diff. */
/* quantize prediction difference d */
y = step_size(state_ptr); /* quantizer step size */
i = quantize(d, y, qtab_723_16, 1); /* i = ADPCM code */
/* Since quantize() only produces a three level output
* (1, 2, or 3), we must create the fourth one on our own
*/
if (i == 3) /* i code for the zero region */
if ((d & 0x8000) == 0) /* If d > 0, i=3 isn't right... */
i = 0;
dq = reconstruct(i & 2, _dqlntab[i], y); /* quantized diff. */
sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconstructed signal */
dqsez = sr + sez - se; /* pole prediction diff. */
update(2, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
return (i);
}
/*
* g726_32_encoder()
*
* Encodes the input vale of linear PCM, A-law or u-law data sl and returns
* the resulting code. -1 is returned for unknown input coding value.
*/
int
g726_32_encoder(
int sl,
int in_coding,
struct g726_state *state_ptr)
{
short sezi, se, sez; /* ACCUM */
short d; /* SUBTA */
short sr; /* ADDB */
short y; /* MIX */
short dqsez; /* ADDC */
short dq, i;
switch (in_coding) { /* linearize input sample to 14-bit PCM */
case AUDIO_ENCODING_LINEAR:
sl >>= 2; /* 14-bit dynamic range */
break;
default:
return (-1);
}
sezi = predictor_zero(state_ptr);
sez = sezi >> 1;
se = (sezi + predictor_pole(state_ptr)) >> 1; /* estimated signal */
d = sl - se; /* estimation difference */
/* quantize the prediction difference */
y = step_size(state_ptr); /* quantizer step size */
i = quantize(d, y, qtab_726_32, 7); /* i = ADPCM code */
dq = reconstruct(i & 8, _dqlntab[i], y); /* quantized est diff */
sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconst. signal */
dqsez = sr + sez - se; /* pole prediction diff. */
update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
return (i);
}
