ref: 7af9c20656f528fe2329d91197d4f83094d7715a
dir: /common/libsndfile/src/G72x/g72x.c/
/*
* This source code is a product of Sun Microsystems, Inc. and is provided
* for unrestricted use. Users may copy or modify this source code without
* charge.
*
* SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
*
* Sun source code is provided with no support and without any obligation on
* the part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
* OR ANY PART THEREOF.
*
* In no event will Sun Microsystems, Inc. be liable for any lost revenue
* or profits or other special, indirect and consequential damages, even if
* Sun has been advised of the possibility of such damages.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
/*
* g72x.c
*
* Common routines for G.721 and G.723 conversions.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "g72x.h"
#include "private.h"
static
short power2 [15] =
{ 1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,
0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000
} ;
/*
* quan()
*
* quantizes the input val against the table of size short integers.
* It returns i if table[i - 1] <= val < table[i].
*
* Using linear search for simple coding.
*/
static
int quan (int val, short *table, int size)
{
int i;
for (i = 0; i < size; i++)
if (val < *table++)
break;
return (i);
}
/*
* fmult()
*
* returns the integer product of the 14-bit integer "an" and
* "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
*/
static
int fmult (int an, int srn)
{
short anmag, anexp, anmant;
short wanexp, wanmant;
short retval;
anmag = (an > 0) ? an : ((-an) & 0x1FFF);
anexp = quan(anmag, power2, 15) - 6;
anmant = (anmag == 0) ? 32 :
(anexp >= 0) ? anmag >> anexp : anmag << -anexp;
wanexp = anexp + ((srn >> 6) & 0xF) - 13;
/*
** The original was :
** wanmant = (anmant * (srn & 0x37) + 0x30) >> 4 ;
** but could see no valid reason for the + 0x30.
** Removed it and it improved the SNR of the codec.
*/
wanmant = (anmant * (srn & 0x37)) >> 4 ;
retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
(wanmant >> -wanexp);
return (((an ^ srn) < 0) ? -retval : retval);
}
/*
* private_init_state()
*
* This routine initializes and/or resets the G72x_PRIVATE structure
* pointed to by 'state_ptr'.
* All the initial state values are specified in the CCITT G.721 document.
*/
void private_init_state (G72x_STATE *state_ptr)
{
int cnta;
state_ptr->yl = 34816;
state_ptr->yu = 544;
state_ptr->dms = 0;
state_ptr->dml = 0;
state_ptr->ap = 0;
for (cnta = 0; cnta < 2; cnta++) {
state_ptr->a[cnta] = 0;
state_ptr->pk[cnta] = 0;
state_ptr->sr[cnta] = 32;
}
for (cnta = 0; cnta < 6; cnta++) {
state_ptr->b[cnta] = 0;
state_ptr->dq[cnta] = 32;
}
state_ptr->td = 0;
} /* private_init_state */
int g72x_reader_init (G72x_DATA *data, int codec)
{ G72x_STATE *pstate ;
if (sizeof (data->private) < sizeof (G72x_STATE))
{ /* This is for safety only. */
return 1 ;
} ;
memset (data, 0, sizeof (G72x_DATA)) ;
pstate = (G72x_STATE*) data->private ;
private_init_state (pstate) ;
pstate->encoder = NULL ;
switch (codec)
{ case G723_16_BITS_PER_SAMPLE : /* 2 bits per sample. */
pstate->decoder = g723_16_decoder ;
data->blocksize = G723_16_BYTES_PER_BLOCK ;
data->samplesperblock = G723_16_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 2 ;
break ;
case G723_24_BITS_PER_SAMPLE : /* 3 bits per sample. */
pstate->decoder = g723_24_decoder ;
data->blocksize = G723_24_BYTES_PER_BLOCK ;
data->samplesperblock = G723_24_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 3 ;
break ;
case G721_32_BITS_PER_SAMPLE : /* 4 bits per sample. */
pstate->decoder = g721_decoder ;
data->blocksize = G721_32_BYTES_PER_BLOCK ;
data->samplesperblock = G721_32_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 4 ;
break ;
case G721_40_BITS_PER_SAMPLE : /* 5 bits per sample. */
pstate->decoder = g723_40_decoder ;
data->blocksize = G721_40_BYTES_PER_BLOCK ;
data->samplesperblock = G721_40_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 5 ;
break ;
default : return 1 ;
} ;
return 0 ;
} /* g72x_reader_init */
int g72x_writer_init (G72x_DATA *data, int codec)
{ G72x_STATE *pstate ;
if (sizeof (data->private) < sizeof (G72x_STATE))
{ /* This is for safety only. Gets optimised out. */
return 1 ;
} ;
memset (data, 0, sizeof (G72x_DATA)) ;
pstate = (G72x_STATE*) data->private ;
private_init_state (pstate) ;
pstate->decoder = NULL ;
switch (codec)
{ case G723_16_BITS_PER_SAMPLE : /* 2 bits per sample. */
pstate->encoder = g723_16_encoder ;
data->blocksize = G723_16_BYTES_PER_BLOCK ;
data->samplesperblock = G723_16_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 2 ;
break ;
case G723_24_BITS_PER_SAMPLE : /* 3 bits per sample. */
pstate->encoder = g723_24_encoder ;
data->blocksize = G723_24_BYTES_PER_BLOCK ;
data->samplesperblock = G723_24_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 3 ;
break ;
case G721_32_BITS_PER_SAMPLE : /* 4 bits per sample. */
pstate->encoder = g721_encoder ;
data->blocksize = G721_32_BYTES_PER_BLOCK ;
data->samplesperblock = G721_32_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 4 ;
break ;
case G721_40_BITS_PER_SAMPLE : /* 5 bits per sample. */
pstate->encoder = g723_40_encoder ;
data->blocksize = G721_40_BYTES_PER_BLOCK ;
data->samplesperblock = G721_40_SAMPLES_PER_BLOCK ;
pstate->codec_bits = 5 ;
break ;
default : return 1 ;
} ;
return 0 ;
} /* g72x_writer_init */
int unpack_bytes (G72x_DATA *data, int bits)
{ unsigned int in_buffer = 0 ;
unsigned char in_byte ;
int k, in_bits = 0, bindex = 0 ;
for (k = 0 ; bindex <= data->blocksize && k < G72x_BLOCK_SIZE ; k++)
{ if (in_bits < bits)
{ in_byte = data->block [bindex++] ;
in_buffer |= (in_byte << in_bits);
in_bits += 8;
}
data->samples [k] = in_buffer & ((1 << bits) - 1);
in_buffer >>= bits;
in_bits -= bits;
} ;
return k ;
} /* unpack_bytes */
int g72x_decode_block (G72x_DATA *data)
{ G72x_STATE *pstate ;
int k, count ;
pstate = (G72x_STATE*) data->private ;
count = unpack_bytes (data, pstate->codec_bits) ;
for (k = 0 ; k < count ; k++)
data->samples [k] = pstate->decoder (data->samples [k], pstate) ;
return 0 ;
} /* g72x_decode_block */
int pack_bytes (G72x_DATA *data, int bits)
{
unsigned int out_buffer = 0 ;
int k, bindex = 0, out_bits = 0 ;
unsigned char out_byte ;
for (k = 0 ; k < G72x_BLOCK_SIZE ; k++)
{ out_buffer |= (data->samples [k] << out_bits) ;
out_bits += bits ;
if (out_bits >= 8)
{ out_byte = out_buffer & 0xFF ;
out_bits -= 8 ;
out_buffer >>= 8 ;
data->block [bindex++] = out_byte ;
}
} ;
return bindex ;
} /* pack_bytes */
int g72x_encode_block (G72x_DATA *data)
{ G72x_STATE *pstate ;
int k, count ;
pstate = (G72x_STATE*) data->private ;
for (k = 0 ; k < data->samplesperblock ; k++)
data->samples [k] = pstate->encoder (data->samples [k], pstate) ;
count = pack_bytes (data, pstate->codec_bits) ;
return count ;
} /* g72x_encode_block */
/*
* predictor_zero()
*
* computes the estimated signal from 6-zero predictor.
*
*/
int predictor_zero (G72x_STATE *state_ptr)
{
int i;
int sezi;
sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
for (i = 1; i < 6; i++) /* ACCUM */
sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
return (sezi);
}
/*
* predictor_pole()
*
* computes the estimated signal from 2-pole predictor.
*
*/
int predictor_pole(G72x_STATE *state_ptr)
{
return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
}
/*
* step_size()
*
* computes the quantization step size of the adaptive quantizer.
*
*/
int step_size (G72x_STATE *state_ptr)
{
int y;
int dif;
int al;
if (state_ptr->ap >= 256)
return (state_ptr->yu);
else {
y = state_ptr->yl >> 6;
dif = state_ptr->yu - y;
al = state_ptr->ap >> 2;
if (dif > 0)
y += (dif * al) >> 6;
else if (dif < 0)
y += (dif * al + 0x3F) >> 6;
return (y);
}
}
/*
* quantize()
*
* Given a raw sample, 'd', of the difference signal and a
* quantization step size scale factor, 'y', this routine returns the
* ADPCM codeword to which that sample gets quantized. The step
* size scale factor division operation is done in the log base 2 domain
* as a subtraction.
*/
int quantize(
int d, /* Raw difference signal sample */
int y, /* Step size multiplier */
short *table, /* quantization table */
int size) /* table size of short integers */
{
short dqm; /* Magnitude of 'd' */
short exp; /* Integer part of base 2 log of 'd' */
short mant; /* Fractional part of base 2 log */
short dl; /* Log of magnitude of 'd' */
short dln; /* Step size scale factor normalized log */
int i;
/*
* LOG
*
* Compute base 2 log of 'd', and store in 'dl'.
*/
dqm = abs(d);
exp = quan(dqm >> 1, power2, 15);
mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */
dl = (exp << 7) + mant;
/*
* SUBTB
*
* "Divide" by step size multiplier.
*/
dln = dl - (y >> 2);
/*
* QUAN
*
* Obtain codword i for 'd'.
*/
i = quan(dln, table, size);
if (d < 0) /* take 1's complement of i */
return ((size << 1) + 1 - i);
else if (i == 0) /* take 1's complement of 0 */
return ((size << 1) + 1); /* new in 1988 */
else
return (i);
}
/*
* reconstruct()
*
* Returns reconstructed difference signal 'dq' obtained from
* codeword 'i' and quantization step size scale factor 'y'.
* Multiplication is performed in log base 2 domain as addition.
*/
int
reconstruct(
int sign, /* 0 for non-negative value */
int dqln, /* G.72x codeword */
int y) /* Step size multiplier */
{
short dql; /* Log of 'dq' magnitude */
short dex; /* Integer part of log */
short dqt;
short dq; /* Reconstructed difference signal sample */
dql = dqln + (y >> 2); /* ADDA */
if (dql < 0) {
return ((sign) ? -0x8000 : 0);
} else { /* ANTILOG */
dex = (dql >> 7) & 15;
dqt = 128 + (dql & 127);
dq = (dqt << 7) >> (14 - dex);
return ((sign) ? (dq - 0x8000) : dq);
}
}
/*
* update()
*
* updates the state variables for each output code
*/
void
update(
int code_size, /* distinguish 723_40 with others */
int y, /* quantizer step size */
int wi, /* scale factor multiplier */
int fi, /* for long/short term energies */
int dq, /* quantized prediction difference */
int sr, /* reconstructed signal */
int dqsez, /* difference from 2-pole predictor */
G72x_STATE *state_ptr) /* coder state pointer */
{
int cnt;
short mag, exp; /* Adaptive predictor, FLOAT A */
short a2p = 0; /* LIMC */
short a1ul; /* UPA1 */
short pks1; /* UPA2 */
short fa1;
char tr; /* tone/transition detector */
short ylint, thr2, dqthr;
short ylfrac, thr1;
short pk0;
pk0 = (dqsez < 0) ? 1 : 0; /* needed in updating predictor poles */
mag = dq & 0x7FFF; /* prediction difference magnitude */
/* TRANS */
ylint = state_ptr->yl >> 15; /* exponent part of yl */
ylfrac = (state_ptr->yl >> 10) & 0x1F; /* fractional part of yl */
thr1 = (32 + ylfrac) << ylint; /* threshold */
thr2 = (ylint > 9) ? 31 << 10 : thr1; /* limit thr2 to 31 << 10 */
dqthr = (thr2 + (thr2 >> 1)) >> 1; /* dqthr = 0.75 * thr2 */
if (state_ptr->td == 0) /* signal supposed voice */
tr = 0;
else if (mag <= dqthr) /* supposed data, but small mag */
tr = 0; /* treated as voice */
else /* signal is data (modem) */
tr = 1;
/*
* Quantizer scale factor adaptation.
*/
/* FUNCTW & FILTD & DELAY */
/* update non-steady state step size multiplier */
state_ptr->yu = y + ((wi - y) >> 5);
/* LIMB */
if (state_ptr->yu < 544) /* 544 <= yu <= 5120 */
state_ptr->yu = 544;
else if (state_ptr->yu > 5120)
state_ptr->yu = 5120;
/* FILTE & DELAY */
/* update steady state step size multiplier */
state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);
/*
* Adaptive predictor coefficients.
*/
if (tr == 1) { /* reset a's and b's for modem signal */
state_ptr->a[0] = 0;
state_ptr->a[1] = 0;
state_ptr->b[0] = 0;
state_ptr->b[1] = 0;
state_ptr->b[2] = 0;
state_ptr->b[3] = 0;
state_ptr->b[4] = 0;
state_ptr->b[5] = 0;
} else { /* update a's and b's */
pks1 = pk0 ^ state_ptr->pk[0]; /* UPA2 */
/* update predictor pole a[1] */
a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);
if (dqsez != 0) {
fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];
if (fa1 < -8191) /* a2p = function of fa1 */
a2p -= 0x100;
else if (fa1 > 8191)
a2p += 0xFF;
else
a2p += fa1 >> 5;
if (pk0 ^ state_ptr->pk[1])
{ /* LIMC */
if (a2p <= -12160)
a2p = -12288;
else if (a2p >= 12416)
a2p = 12288;
else
a2p -= 0x80;
}
else if (a2p <= -12416)
a2p = -12288;
else if (a2p >= 12160)
a2p = 12288;
else
a2p += 0x80;
}
/* TRIGB & DELAY */
state_ptr->a[1] = a2p;
/* UPA1 */
/* update predictor pole a[0] */
state_ptr->a[0] -= state_ptr->a[0] >> 8;
if (dqsez != 0)
{ if (pks1 == 0)
state_ptr->a[0] += 192;
else
state_ptr->a[0] -= 192;
} ;
/* LIMD */
a1ul = 15360 - a2p;
if (state_ptr->a[0] < -a1ul)
state_ptr->a[0] = -a1ul;
else if (state_ptr->a[0] > a1ul)
state_ptr->a[0] = a1ul;
/* UPB : update predictor zeros b[6] */
for (cnt = 0; cnt < 6; cnt++) {
if (code_size == 5) /* for 40Kbps G.723 */
state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;
else /* for G.721 and 24Kbps G.723 */
state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;
if (dq & 0x7FFF) { /* XOR */
if ((dq ^ state_ptr->dq[cnt]) >= 0)
state_ptr->b[cnt] += 128;
else
state_ptr->b[cnt] -= 128;
}
}
}
for (cnt = 5; cnt > 0; cnt--)
state_ptr->dq[cnt] = state_ptr->dq[cnt-1];
/* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
if (mag == 0) {
state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;
} else {
exp = quan(mag, power2, 15);
state_ptr->dq[0] = (dq >= 0) ?
(exp << 6) + ((mag << 6) >> exp) :
(exp << 6) + ((mag << 6) >> exp) - 0x400;
}
state_ptr->sr[1] = state_ptr->sr[0];
/* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
if (sr == 0) {
state_ptr->sr[0] = 0x20;
} else if (sr > 0) {
exp = quan(sr, power2, 15);
state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp);
} else if (sr > -32768) {
mag = -sr;
exp = quan(mag, power2, 15);
state_ptr->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400;
} else
state_ptr->sr[0] = (short) 0xFC20;
/* DELAY A */
state_ptr->pk[1] = state_ptr->pk[0];
state_ptr->pk[0] = pk0;
/* TONE */
if (tr == 1) /* this sample has been treated as data */
state_ptr->td = 0; /* next one will be treated as voice */
else if (a2p < -11776) /* small sample-to-sample correlation */
state_ptr->td = 1; /* signal may be data */
else /* signal is voice */
state_ptr->td = 0;
/*
* Adaptation speed control.
*/
state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */
state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */
if (tr == 1)
state_ptr->ap = 256;
else if (y < 1536) /* SUBTC */
state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
else if (state_ptr->td == 1)
state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=
(state_ptr->dml >> 3))
state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
else
state_ptr->ap += (-state_ptr->ap) >> 4;
return ;
} /* update */