g727.c

Reference Implementation of G.711 standard and other voice codecs

/*                                                          19.May.2000 v1.02
=============================================================================

                          U    U   GGG    SSSS  TTTTT
                          U    U  G       S       T
                          U    U  G  GG   SSSS    T
                          U    U  G   G       S   T
                           UUU     GG     SSS     T

                   ========================================
                    ITU-T - USER'S GROUP ON SOFTWARE TOOLS
                   ========================================


       =============================================================
       COPYRIGHT NOTE: This source code, and all of its derivations,
       is subject to the "ITU-T General Public License". Please have
       it  read  in    the  distribution  disk,   or  in  the  ITU-T
       Recommendation G.191 on "SOFTWARE TOOLS FOR SPEECH AND  AUDIO
       CODING STANDARDS".
       =============================================================


MODULE: G727.C, G.727 embedded ADPCM algorithm operating with
                      5-, 4-, 3-, and 2-bits per sample

ORIGINAL BY:

     Nikolai L. Birioukov
     Maxim A. Lagerev

     Ukrainian Research Institut of Telecommunications

     P.O. 252650
     13, Solomenskaya St.
     Kiev, Ukraine

     Phone : [phone]
     FAX   : [phone]
     EMail : INFO@UNIIS,KIEV,UA

FUNCTIONS:

  G727_reset ...... G727 reset function;
  G727_encode ..... G727 encoder function;
  G727_decode ..... G727 decoder function;

HISTORY:
  01.Apr.1995  0.98  Version of the G727 module in C++ code
  10.Jul.1996  0.99  C code version released to UGST <[e-mail]>
  10.Mar.1997  1.00  Conversion to UGST format <[e-mail]>
  04.Aug.1997  1.01  Eliminated compilation warning about unused variables
                     as per revision from <[e-mail]>
  19.May.2000  v1.02 Corrected self-documentation of functions. <simao>
=============================================================================
*/

#include <assert.h>
#include "g727.h"

/* Local function prototypes */
Int16 g727_get_d ARGS((Int8 s, Int16 se, short law));
Int16 g727_expand ARGS((Int8 sp, short law));
Int16 g727_subta ARGS((Int16 sl, Int16 se));
Int8 g727_get_in ARGS((Int16 d, Int16 y, short rate));
void g727_log ARGS((Int16 *dl, Int8 *ds, Int16 d));
Int8 g727_quan ARGS((Int16 dln, Int8 ds, short rate));
Int16 g727_subtb ARGS((Int16 dl, Int16 y));
Int8 g727_get_ic ARGS((Int8 in, short enh));
Int16 g727_get_dq ARGS((Int16 y, Int8 in, short rate));
Int16 g727_antilog ARGS((Int16 dql, Int8 dqs));
Int16 g727_adda ARGS((Int16 dqln, Int16 y));
void g727_reconst ARGS((Int16 *dqln, Int8 *dqs, Int8 in, short rate));
void g727_qsfa_reset ARGS((g727_qsfa_state *st));
Int16 g727_get_y ARGS((g727_qsfa_state *st, Int8 al));
Int32 g727_get_yl ARGS((g727_qsfa_state *st));
void g727_qsfa_transit ARGS((g727_qsfa_state *st, Int8 in, Int16 y,
			     short rate));
Int16 g727_filtd ARGS((Int16 wi, Int16 y));
Int32 g727_filte ARGS((g727_qsfa_state *st, Int16 yup));
Int16 g727_functw ARGS((Int8 in, short rate));
Int16 g727_limb ARGS((Int16 yut));
Int16 g727_mix ARGS((g727_qsfa_state *st, Int8 al));
void g727_asc_reset ARGS((g727_asc_state *st));
Int8 g727_get_al ARGS((g727_asc_state *st));
void g727_asc_transit ARGS((g727_asc_state *st, Int8 in, Int16 y, Int8 tr,
			    Int8 tdp, short rate));
Int16 g727_filta ARGS((g727_asc_state *st, Int8 fi));
Int16 g727_filtb ARGS((g727_asc_state *st, Int8 fi));
Int16 g727_filtc ARGS((g727_asc_state *st, Int8 ax));
Int8 g727_functf ARGS((Int8 in, short rate));
Int8 g727_lima ARGS((g727_asc_state *st));
Int8 g727_subtc ARGS((Int16 dmsp, Int16 dmlp, Int8 tdp, Int16 y));
Int16 g727_triga ARGS((Int8 tr, Int16 app));
void g727_aprsc_reset ARGS((g727_aprsc_state *st));
Int16 g727_get_sr ARGS((Int16 dq, Int16 se));
void g727_get_se_sez ARGS((g727_aprsc_state *st, Int16 *se, Int16 *sez));
Int16 g727_get_a2p ARGS((g727_aprsc_state *st, Int16 dq, Int16 sez,
			 Int8 *pk0, Int8 *sigpk));
void g727_aprsc_transit ARGS((g727_aprsc_state *st, Int16 dq, Int8 tr,
			      Int16 sr, Int16 a2p, Int8 pk0, Int8 sigpk));
void g727_accum ARGS((Int16 *se, Int16 *sez, Int16 wa1, Int16 wa2, Int16 wb1,
		      Int16 wb2, Int16 wb3, Int16 wb4, Int16 wb5, Int16 wb6));
Int16 g727_addb ARGS((Int16 dq, Int16 se));
void g727_addc ARGS((Int8 *pk0, Int8 *sigpk, Int16 dq, Int16 sez));
Int8 g727_makexp ARGS((Int16 mag));
Int16 g727_floata ARGS((Int16 dq));
Int16 g727_floatb ARGS((Int16 sr));
Int16 g727_fmult ARGS((Int16 an, Int16 srn));
Int16 g727_limc ARGS((Int16 a2t));
Int16 g727_limd ARGS((Int16 a1t, Int16 a2p));
Int16 g727_aprsc_trigb ARGS((Int8 tr, Int16 anp));
Int16 g727_upa1 ARGS((g727_aprsc_state *st, Int8 pk0, Int8 sigpk));
Int16 g727_upa2 ARGS((g727_aprsc_state *st, Int8 pk0, Int8 sigpk));
Int16 g727_upb ARGS((Int8 un, Int16 bn, Int16 dq));
Int8 g727_xor ARGS((Int16 dqn, Int16 dq));
Int16 g727_get_srff ARGS((Int16 dqff, Int16 se));
void g727_ttd_reset ARGS((g727_ttd_state *st));
Int8 g727_get_tr ARGS((g727_ttd_state *st, Int32 yl, Int16 dq));
Int8 g727_get_tdp ARGS((Int16 a2p));
void g727_ttd_transit ARGS((g727_ttd_state *st, Int8 tr, Int8 tdp));
Int8 g727_tone ARGS((Int16 a2p));
Int8 g727_trans ARGS((g727_ttd_state *st, Int32 yl, Int16 dq));
Int8 g727_ttd_trigb ARGS((Int8 tr, Int8 tdp));
Int8 g727_get_sd ARGS((Int16 sr, Int16 se, Int8 in, Int16 y, short law,
		       short rate));
Int8 g727_compress ARGS((Int16 sr, short law));
Int8 g727_sync ARGS((Int8 in, Int8 sp, Int16 dlnx, short law, Int8 ds,
		     short rate));




/*---------- Constant tables ----------*/

static Int16 g727_dqlnTable40[32] = {
    3832, 4035,   34,   97,  145,  184,  217,  246,
     273,  298,  321,  344,  367,  391,  419,  456,
     456,  419,  391,  367,  344,  321,  298,  273,
     246,  217,  184,  145,   97,   34, 4035, 3832
};

static Int16 g727_dqlnTable32[16] = {
    3961,   68,  165,  232,  285,  332,  377,  428,
     428,  377,  332,  285,  232,  165,   68, 3961
};

static Int16 g727_dqlnTable24[8] = {
    4085,  199,  307,  395,  395,  307,  199, 4085
};

static Int16 g727_dqlnTable16[4] = {
    116, 365, 365, 116
};

static Int16 g727_wiTable32[8] = {
    4084, 4, 27, 50, 98, 184, 340, 1108
};

static Int16 g727_wiTable24[4] = {
    4092, 30, 137, 582
};

static Int16 g727_wiTable16[2] = {
    4074, 439
};

static Int8 g727_fiTable32[8] = {
    0, 0, 0, 1, 1, 1, 3, 7
};

static Int8 g727_fiTable24[4] = {
    0, 1, 2, 7
};

static Int8 g727_fiTable16[2] = {
    0, 7
};


/*---------- G.727 ADPCM Encoder & Decoder ----------*/


/*
  ----------------------------------------------------------------------------

  void g727_reset (g727_state *st);

  Description:
  ~~~~~~~~~~~~

  Reset ITU-T G.727 embedded ADPCM encoder or decoder state variable.
  The state variable is defined in g727.h.

  Return value:
  ~~~~~~~~~~~~~
  None.

  Prototype:      in file g727.h
  ~~~~~~~~~~

  History:
  ~~~~~~~~
  10.Jul.96  0.99  C code version released to UGST <[e-mail]>
  10.Mar.97  1.00  Conversion to UGST format <[e-mail]>
 ----------------------------------------------------------------------------
*/
void
g727_reset(g727_state *st)
{
    g727_qsfa_reset(&st->qsfa);
    g727_asc_reset(&st->asc);
    g727_aprsc_reset(&st->aprsc);
    g727_ttd_reset(&st->ttd);
}
/* ........................ End of G727_reset() ........................ */



/*
  ----------------------------------------------------------------------------

  void g727_encode_block (short *src, short *dst, short n, 
  ~~~~~~~~~~~~~~~~~~~~~~  short law, short cbits, short ebits, g727_state *st);

  Description:
  ~~~~~~~~~~~~

  Simulation of the ITU-T G.727 embedded ADPCM encoder. Takes the A or
  mu law input array of shorts `src' (16 bit, right- justified,
  without sign extension) of length `n', and saves the encoded samples
  in the array of shorts `dst', with the same number of samples and
  right-justified. The ADPCM samples will have cbits core bits, and
  ebits enhancement bits.

  The state variables are saved in the structure `g727_state'. The law
  is A if `law'=='1', and mu law if `law'=='0'.
	
  Parameters:
  ~~~~~~~~~~~
  src .......... A- or u-law 16-bit right justified sample to encode
  dst .......... 16-bit right justified ADPCM-encoded sample with cbits
                 core bits and ebits enhancement bits
  n ............ Number of samples to encode.
  law .......... encoding law (character '1'=A-law, character '0'=u-law).
  cbits ........ number of core bits
  ebits ........ number of enhancement bits
  g727_state ... G.727 state variable structure

  Return value:
  ~~~~~~~~~~~~~
  None.

  Prototype:      in file g727.h
  ~~~~~~~~~~

  History:
  ~~~~~~~~
  10.Jul.96  0.99  C code version released to UGST <[e-mail]>
  10.Mar.97  1.00  Conversion to UGST format <[e-mail]>
 ----------------------------------------------------------------------------
*/
void
g727_encode_block(short *src, short *dst, short n, short law, short cbits,
                                                              short ebits,
                                                              g727_state *st)
{
    short *eptr = src + n;

    /* Fix for compatibility with g726_encode() definitions */
    if (law == '1')
      law = 1;
    else if (law == '0')
      law = 0;

    /* Encode all samples in buffer */
    while (src < eptr)
        *dst++ = g727_encode_sample(*src++, law, cbits, ebits, st);
}
/* ..................... End of G727_encode_block() ..................... */


/*
  ----------------------------------------------------------------------------

  void g727_decode_block (short *src, short *dst, short n,
  ~~~~~~~~~~~~~~~~~~~~~~  short law, short cbits, short ebits, g727_state *st);

  Description:
  ~~~~~~~~~~~~

  Simulation of the ITU-T G.727 embedded ADPCM decoder. Takes the
  ADPCM input array of shorts `src' (16 bit, right- justified, without
  sign extension) of length `n', and saves the decoded samples (A or
  mu law) in the array of shorts `dst', with the same number of
  samples and right-justified. The ADPCM samples must have cbits core
  bits, and ebits enhancement bits.

  The state variables are saved in the structure `g727_state'. The law
  is A if `law'=='1', and mu law if `law'=='0'.

	
  Parameters:
  ~~~~~~~~~~~
  src .......... 16-bit right justified ADPCM-encoded sample with cbits
                 core bits and ebits enhancement bits
  dst .......... A- or u-law 16-bit right justified sample to encode
  n ............ Number of samples to encode.
  law .......... encoding law (character '1'=A-law, character '0'=u-law).
  cbits ........ number of core bits
  ebits ........ number of enhancement bits
  g727_state ... G.727 state variable structure

  Return value:
  ~~~~~~~~~~~~~
  None.

  Prototype:      in file g727.h
  ~~~~~~~~~~

  History:
  ~~~~~~~~
  10.Jul.96  0.99  C code version released to UGST <[e-mail]>
  10.Mar.97  1.00  Conversion to UGST format <[e-mail]>
 ----------------------------------------------------------------------------
*/
void
g727_decode_block(short *src, short *dst, short n, short law, short cbits,
                                                              short ebits,
                                                              g727_state *st)
{
    short *eptr = src + n;

    /* Fix for compatibility with g726_decode() definitions */
    if (law == '1')
      law = 1;
    else if (law == '0')
      law = 0;

    /* Decode all samples in buffer */
    while (src < eptr)
        *dst++ = g727_decode_sample(*src++, law, cbits, ebits, st);
}
/* ...................... End of G727_decode_block() ..................... */


/*
  ----------------------------------------------------------------------------

  short g727_encode_sample (short code, short law, short cbits, 
  ~~~~~~~~~~~~~~~~~~~~~~~~  short ebits, g727_state *st);

  Description:
  ~~~~~~~~~~~~

  Simulation of the ITU-T G.727 embedded ADPCM encoder. Takes one A or
  mu law (16 bit, right- justified, without sign extension) sample in
  'code' and returns the ADPCM-encoded sample using the law and number
  of core and enhancement bits specified by the user.  Samples are
  returned right-justified.

  The state variables are saved in the structure `g727_state'. The law
  is A if `law'=='1', and mu law if `law'=='0'.
	
  Parameters:
  ~~~~~~~~~~~
  code ......... A- or u-law 16-bit right justified sample to encode
  law .......... encoding law (character '1'=A-law, character '0'=u-law).
  cbits ........ number of core bits
  ebits ........ number of enhancement bits
  g727_state ... G.727 state variable structure

  Return value:
  ~~~~~~~~~~~~~
  16-bit right justified ADPCM-encoded sample with cbits core bits and
  ebits enhancement bits

  Prototype:      in file g727.h
  ~~~~~~~~~~

  History:
  ~~~~~~~~
  10.Jul.96  0.99  C code version released to UGST <[e-mail]>
  10.Mar.97  1.00  Conversion to UGST format <[e-mail]>
 ----------------------------------------------------------------------------
*/
short g727_encode_sample(short code, short law, short cbits, short ebits, g727_state *st)
{
  Int16 se;
  Int16 sez;
  Int8 al;
  Int16 y;
  Int32 yl;
  Int16 d;
  Int8 in;
  Int8 ic;
  Int16 dq;
  Int16 sr;
  Int8 pk0;
  Int8 sigpk;
  Int16 a2p;
  Int8 tr;
  Int8 tdp;

  assert(2 <= cbits && cbits <= 4 && ebits >= 0 && cbits + ebits <= 5);

    g727_get_se_sez(&st->aprsc, &se, &sez);

    al = g727_get_al(&st->asc);

    y = g727_get_y(&st->qsfa, al);
    yl = g727_get_yl(&st->qsfa);

    d = g727_get_d((Int8)code, se, law);

    in = g727_get_in(d, y, cbits + ebits);
    ic = g727_get_ic(in, ebits);

    dq = g727_get_dq(y, ic, cbits);

    sr = g727_get_sr(dq, se);
    a2p = g727_get_a2p(&st->aprsc, dq, sez, &pk0, &sigpk);

    tr = g727_get_tr(&st->ttd, yl, dq);
    tdp = g727_get_tdp(a2p);

    g727_qsfa_transit(&st->qsfa, ic, y, cbits);
    g727_asc_transit(&st->asc, ic, y, tr, tdp, cbits);
    g727_aprsc_transit(&st->aprsc, dq, tr, sr, a2p, pk0, sigpk);
    g727_ttd_transit(&st->ttd, tr, tdp);

    return in;
}
/* ..................... End of G727_encode_sample() ..................... */


/*
  ----------------------------------------------------------------------------

  void g727_decode_sample (short code, short law, short cbits, 
  ~~~~~~~~~~~~~~~~~~~~~~~  short ebits, g727_state *st);

  Description:
  ~~~~~~~~~~~~

  Simulation of the ITU-T G.727 embedded ADPCM decoder. Takes the
  ADPCM short sample in 'code' (16 bit, right- justified, without sign
  extension), and returns the decoded sample (A or mu law),
  right-justified.

  The state variables are saved in the structure `g727_state'. The law
  is A if `law'=='1', and mu law if `law'=='0'.
	
  Parameters:
  ~~~~~~~~~~~
  code ......... 16-bit right justified ADPCM-encoded sample with cbits
                 core bits and ebits enhancement bits
  law .......... encoding law (character '1'=A-law, character '0'=u-law).
  cbits ........ number of core bits
  ebits ........ number of enhancement bits
  g727_state ... G.727 state variable structure

  Return value:
  ~~~~~~~~~~~~~
  16-bit right justified decoded A- or u-law sample

  Prototype:      in file g727.h
  ~~~~~~~~~~

  History:
  ~~~~~~~~
  10.Jul.96  0.99  C code version released to UGST <[e-mail]>
  10.Mar.97  1.00  Conversion to UGST format <[e-mail]>
 ----------------------------------------------------------------------------
*/
short
g727_decode_sample(short code, short law, short cbits, short ebits, g727_state *st)
{
    Int8 ic;
    Int8 al;
    Int16 y;
    Int32 yl;
    short rt;
    Int16 dqfb;
    Int16 dqff;
    Int16 se;
    Int16 sez;
    Int16 srfb;
    Int8 pk0;
    Int8 sigpk;
    Int16 a2p;
    Int16 srff;
    Int8 tr;
    Int8 tdp;
    Int8 sd;

    assert(2 <= cbits && cbits <= 4 && ebits >= 0 && cbits + ebits <= 5);


    ic = g727_get_ic((Int8)code, ebits);

    al = g727_get_al(&st->asc);

    y = g727_get_y(&st->qsfa, al);
    yl = g727_get_yl(&st->qsfa);

    rt = cbits + ebits;

    dqfb = g727_get_dq(y, ic, cbits);
    dqff = g727_get_dq(y, (Int8)code, rt);

    g727_get_se_sez(&st->aprsc, &se, &sez);
    srfb = g727_get_sr(dqfb, se);
    a2p = g727_get_a2p(&st->aprsc, dqfb, sez, &pk0, &sigpk);

    srff = g727_get_srff(dqff, se);

    tr = g727_get_tr(&st->ttd, yl, dqfb);
    tdp = g727_get_tdp(a2p);

    sd = g727_get_sd(srff, se, (Int8)code, y, law, rt);

    g727_qsfa_transit(&st->qsfa, ic, y, cbits);