/*                                                           v2.0 24.Jan.2000=============================================================================                          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:         G726.C ADPCM AT 40, 32, 24, AND 16 KBIT/S MODULEORIGINAL BY:   Jose' Sindi Yamamoto (Fortran version of the G.721)       <tdsindi@venus.cpqd.ansp.br>   Simao Ferraz de Campos Neto (C translation, adaptation&testing of the G.721)       <simao@venus.cpqd.ansp.br>   Fernando Tofolli Queiroz (Extension of the G.721 to the other rates=>G.726)       <tofolli@venus.cpqd.ansp.br>   Simao Ferraz de Campos Neto (Adaptation and testing of the G.726)       <simao@venus.cpqd.ansp.br>HISTORY:28.Feb.1994 v1.0c Version 1.0 in C, by translating Fortran to C (f2c)24.Jan.2000 v2.0  Corrected bug G726_compress() that caused incorrect                   processing of test vector ri40fa. Corrected code                  provided by Jayesh Patel <jayesh@dspse.com>. 		  Verified by <simao.campos@labs.comsat.com>FUNCTIONS:Public:  G726_encode ..... G726 encoder function;  G726_decode ..... G726 decoder function;Private:  G726_accum ...... addition of predictor outputs to form the partial                    signal estimate (from the sixth order predictor) and                    the signal estimate.  G726_adda ....... addition of scale factor to logarithmic version of                    quantized difference signal.  G726_addb ....... addition of quantized difference signal and signal                    estimate to form reconstructed signal.  G726_addc....... obtain sign of addition of quantized difference signal                    and partial signal estimate.  G726_antilog .... convert quantized difference signal from the                    logarithmic to the linear domain.  G726_compress ... convert from uniform pcm to either a-law or u-law pcm.  G726_delaya ..... memory block.  G726_delayb ..... memory block.  G726_delayc ..... memory block.  G726_delayd ..... memory block.  G726_expand ..... convert either a-law (law=1) or u-law (law=0) to                    uniform pcm.  G726_filta ...... update of short term average of f(i).  G726_filtb ...... update of long term average of f(i).  G726_filtc ...... low pass filter of speed control parameter.  G726_filtd ...... update of fast quantizer scale factor.  G726_filte ...... update of slow quantizer scale factor.  G726_floata ..... convert 15-bit signed magnitude to floating point.  G726_floatb ..... convert 16-bit two's complement to floating point.  G726_fmult ...... multiply predictor coefficients with corresponding                    quantized difference signal or reconstructed signal.                    Multiplication is done in floating point format.  G726_functf ..... map quantizer output into the f(i) function.  G726_functw ..... map quantizer output into logarithmic version of scale                    factor multiplier.  G726_lima ....... limit speed control parameter.  G726_limb ....... limit quantizer scale factor.  G726_limc ....... limits on a2 coefficient of second order predictor.  G726_limd ....... limits on a1 coefficient of second order predictor.  G726_log ........ convert difference signal from linear to the                    logarithmic domain.  G726_mix ........ form linear combination of fast and slow quantizer                    scale factors.  G726_quan ....... quantize difference signal in logarithmic domain.  G726_reconst .... reconstruction of quantized difference signal in the                    logarithmic domain.  G726_subta ...... compute difference signal by subtracting signal                    estimate from input signal (or quantized reconstructed                    signal in decoder).  G726_subtb ...... scale logarithmic version of difference signal by                    subtracting scale factor.  G726_subtc ...... compute magnitude of the difference of short and                    long-term function of quantizer output sequence and                    then perform threshold comparison for quantizing speed                    control parameter.  G726_sync ....... re-encode output pcm sample in decoder for synchronous                    tandem coding.  G726_tone ....... partial band signal detection.  G726_trans ...... transition detector.  G726_triga ...... speed control trigger block.  G726_trigb ...... predictor trigger block.  G726_upa1 ....... update a1 coefficient of second order predictor.  G726_upa2 ....... update a2 coefficient of second order predictor.  G726_upb ........ update for coefficients of sixth order predictor.  G726_xor ........ one bit "exclusive or" of sign of difference  signal                    and sign of delayed difference signal.=============================================================================*//* *  .................. INCLUDES .................. */#include "g726.h"/* *  .................. FUNCTIONS .................. *//*  ----------------------------------------------------------------------------        void G726_encode (short *inp_buf, short *out_buf, long smpno,        ~~~~~~~~~~~~~~~~  char *law, short rate, short r, G726_state *state);        Description:        ~~~~~~~~~~~~        Simulation of the ITU-T G.726 ADPCM encoder. Takes the A or mu        law input array of shorts `inp_buf' (16 bit, right- justified,        without sign extension) of length `smpno', and saves the        encoded samples in the array of shorts `out_buf', with the        same number of samples and right-justified.        The state variables are saved in the structure `state', and the        reset can be stablished by making r equal to 1. The law is A if        `law'=='1', and mu law if `law'=='0'.	        Return value:        ~~~~~~~~~~~~~        None.        Prototype:      in file g726.h        ~~~~~~~~~~        History:        ~~~~~~~~        31.Jan.91 v1.0f Version 1.0 in Fortran                        <tdsindi@venus.cpqd.ansp.br>        05.Feb.92 v1.0c Version 1.0 in C, by translating Fortran to C (f2c)                        <tdsimao@venus.cpqd.ansp.br> ----------------------------------------------------------------------------*/void            G726_encode(inp_buf, out_buf, smpno, law, rate, r, state)  short          *inp_buf, *out_buf;  long            smpno;  char           *law;  short           r;  short           rate;  G726_state     *state;{  short           s;  short           d, i;  short           y;  short           sigpk;  short           sr, tr;  short           yu;  short           al, fi, dl, ap, dq, ds, se, ax, td, sl, wi;  short           u1, u2, u3, u4, u5, u6;  short           a1, a2, b1, b2, b3, b4, b5, b6;  short           dqln;  short           a1p, a2p, a1t, a2t, b1p, b2p, b3p, b4p, b5p, b6p, dq6, pk2,                  sr2, wa1, wa2, wb1, wb2, wb3, wb4, wb5, wb6;  short           dml, dln, app, dql, dms;  short           dqs, tdp;  short           sez;  short           yut;  long            yl;  long            j;  /* Invert even bits if A law */  if (*law == '1')  {    for (j = 0; j < smpno; j++)      inp_buf[j] ^= 85;  }  /* Process all desired samples in inp_buf to out_buf; The comments about   * general blocks are given as in G.726, and refer to: 4.1.1 Input PCM   * format conversion and difference signal computation    4.1.2 Adaptive   * quantizer 4.1.3 Inverse adaptive quantizer 4.1.4 Quantizer scale factor   * adaptation 4.1.5 Adaptation speed control 4.1.6 Adaptive predictor and   * reconstructed signal calculator 4.1.7 Tone and transition detector 4.1.8   * (Only in the decoder) */  for (j = 0; j < smpno; j++, r = 0)  {    s = inp_buf[j];    /* Process `known-state' part of 4.2.6 */    G726_delayd(&r, &state->sr1, &sr2);    G726_delayd(&r, &state->sr0, &state->sr1);    G726_delaya(&r, &state->a2r, &a2);    G726_delaya(&r, &state->a1r, &a1);    G726_fmult(&a2, &sr2, &wa2);    G726_fmult(&a1, &state->sr1, &wa1);    G726_delayd(&r, &state->dq5, &dq6);    G726_delayd(&r, &state->dq4, &state->dq5);    G726_delayd(&r, &state->dq3, &state->dq4);    G726_delayd(&r, &state->dq2, &state->dq3);    G726_delayd(&r, &state->dq1, &state->dq2);    G726_delayd(&r, &state->dq0, &state->dq1);    G726_delaya(&r, &state->b1r, &b1);    G726_delaya(&r, &state->b2r, &b2);    G726_delaya(&r, &state->b3r, &b3);    G726_delaya(&r, &state->b4r, &b4);    G726_delaya(&r, &state->b5r, &b5);    G726_delaya(&r, &state->b6r, &b6);    G726_fmult(&b1, &state->dq1, &wb1);    G726_fmult(&b2, &state->dq2, &wb2);    G726_fmult(&b3, &state->dq3, &wb3);    G726_fmult(&b4, &state->dq4, &wb4);    G726_fmult(&b5, &state->dq5, &wb5);    G726_fmult(&b6, &dq6, &wb6);    G726_accum(&wa1, &wa2, &wb1, &wb2, &wb3, &wb4, &wb5, &wb6, &se, &sez);    /* Process 4.2.1 */    G726_expand(&s, law, &sl);    G726_subta(&sl, &se, &d);    /* Process delays and `know-state' part of 4.2.5 */    G726_delaya(&r, &state->dmsp, &dms);    G726_delaya(&r, &state->dmlp, &dml);    G726_delaya(&r, &state->apr, &ap);    G726_lima(&ap, &al);    /* Process `know-state' parts of 4.2.4 */    G726_delayb(&r, &state->yup, &yu);    G726_delayc(&r, &state->ylp, &yl);    G726_mix(&al, &yu, &yl, &y);    /* Process 4.2.2 */    G726_log(&d, &dl, &ds);    G726_subtb(&dl, &y, &dln);    G726_quan(rate, &dln, &ds, &i);    /* Save ADPCM quantized sample into output buffer */    out_buf[j] = i;    /* Process 4.2.3 */    G726_reconst(rate, &i, &dqln, &dqs);    G726_adda(&dqln, &y, &dql);    G726_antilog(&dql, &dqs, &dq);    /* Part of 4.2.5 */    G726_functf(rate, &i, &fi);    G726_filta(&fi, &dms, &state->dmsp);    G726_filtb(&fi, &dml, &state->dmlp);    /* Remaining part of 4.2.4 */    G726_functw(rate, &i, &wi);    G726_filtd(&wi, &y, &yut);    G726_limb(&yut, &state->yup);    G726_filte(&state->yup, &yl, &state->ylp);    /* Process `known-state' part of 4.2.7 */    G726_delaya(&r, &state->tdr, &td);    G726_trans(&td, &yl, &dq, &tr);    /* More `known-state' parts of 4.2.6: update of `pk's */    G726_delaya(&r, &state->pk1, &pk2);    G726_delaya(&r, &state->pk0, &state->pk1);    G726_addc(&dq, &sez, &state->pk0, &sigpk);    /* 4.2.6: find sr0 */    G726_addb(&dq, &se, &sr);    G726_floatb(&sr, &state->sr0);    /* 4.2.6: find dq0 */    G726_floata(&dq, &state->dq0);    /* 4.2.6: prepar a2(r) */    G726_upa2(&state->pk0, &state->pk1, &pk2, &a2, &a1, &sigpk, &a2t);    G726_limc(&a2t, &a2p);    G726_trigb(&tr, &a2p, &state->a2r);    /* 4.2.6: prepar a1(r) */    G726_upa1(&state->pk0, &state->pk1, &a1, &sigpk, &a1t);    G726_limd(&a1t, &a2p, &a1p);    G726_trigb(&tr, &a1p, &state->a1r);    /* Remaining of 4.2.7 */    G726_tone(&a2p, &tdp);    G726_trigb(&tr, &tdp, &state->tdr);    /* Remaining of 4.2.5 */    G726_subtc(&state->dmsp, &state->dmlp, &tdp, &y, &ax);    G726_filtc(&ax, &ap, &app);    G726_triga(&tr, &app, &state->apr);    /* Remaining of 4.2.6: update of all `b's */    G726_xor(&state->dq1, &dq, &u1);	/* Here, b1 */    G726_upb(rate, &u1, &b1, &dq, &b1p);    G726_trigb(&tr, &b1p, &state->b1r);    G726_xor(&state->dq2, &dq, &u2);	/* Here, b2 */    G726_upb(rate, &u2, &b2, &dq, &b2p);    G726_trigb(&tr, &b2p, &state->b2r);    G726_xor(&state->dq3, &dq, &u3);	/* Here, b3 */    G726_upb(rate, &u3, &b3, &dq, &b3p);    G726_trigb(&tr, &b3p, &state->b3r);    G726_xor(&state->dq4, &dq, &u4);	/* Here, b4 */    G726_upb(rate, &u4, &b4, &dq, &b4p);    G726_trigb(&tr, &b4p, &state->b4r);    G726_xor(&state->dq5, &dq, &u5);	/* Here, b5 */    G726_upb(rate, &u5, &b5, &dq, &b5p);    G726_trigb(&tr, &b5p, &state->b5r);    G726_xor(&dq6, &dq, &u6);	/* At last, b6 */    G726_upb(rate, &u6, &b6, &dq, &b6p);    G726_trigb(&tr, &b6p, &state->b6r);  }}/* ........................ end of G726_encode() ....................... *//*  ----------------------------------------------------------------------------        void G726_decode (short *inp_buf, short *out_buf, long smpno,        ~~~~~~~~~~~~~~~~  char *law, short rate, short r, G726_state *state);        Description:        ~~~~~~~~~~~~        Simulation of the ITU-T G.726 ADPCM decoder. Takes the ADPCM        input array of shorts `inp_buf' (16 bit, right- justified,        without sign extension) of length `smpno', and saves the        decoded samples (A or mu law) in the array of shorts        `out_buf', with the same number of samples and        right-justified.        The state variables are saved in the structure `state', and the        reset can be stablished by making r equal to 1. The law is A if        `law'=='1', and mu law if `law'=='0'.	        Return value:        ~~~~~~~~~~~~~        None.        Prototype:      in file g726.h        ~~~~~~~~~~        History:        ~~~~~~~~        31.Jan.91 v1.0f Version 1.0 in Fortran                        <tdsindi@venus.cpqd.ansp.br>        05.Feb.92 v1.0c Version 1.0 in C, by translating Fortran to C (f2c)                        <tdsimao@venus.cpqd.ansp.br> ----------------------------------------------------------------------------*/void            G726_decode(inp_buf, out_buf, smpno, law, rate, r, state)  short          *inp_buf, *out_buf;  long            smpno;  char           *law;  short           r;  short           rate;  G726_state     *state;{  short           i;  short           y;  short           sigpk;  short           sr, tr;  short           sp, dlnx, dsx, sd, slx, dlx, dx;	/* these are unique to							 * the decoder */  long            yl;  short           yu;  short           al, fi, ap, dq, se, ax, td, wi;  short           u1, u2, u3, u4, u5, u6;  short           a1, a2, b1, b2, b3, b4, b5, b6;  short           dqln;  short           a1p, a2p, a1t, a2t, b1p, b2p, b3p, b4p, b5p, b6p, dq6, pk2,                  sr2, wa1, wa2, wb1, wb2, wb3, wb4, wb5, wb6;  short           dml, app, dql, dms;  short           dqs, tdp;  short           sez;  short           yut;  long            j;  /* Process all desired samples in inp_buf to out_buf; The comments about   * general blocks are given as in G.726, and refer to: 4.1.1 Input PCM   * format conversion and difference signal computation    4.1.2 Adaptive   * quantizer 4.1.3 Inverse adaptive quantizer 4.1.4 Quantizer scale factor   * adaptation 4.1.5 Adaptation speed control 4.1.6 Adaptive predictor and   * reconstructed signal calculator 4.1.7 Tone and transition detector 4.1.8   * Output PCM format conversion and synchronous coding adjustment */  for (j = 0; j < smpno; j++, r = 0)  {    /* Process `known-state' part of 4.2.6 */    G726_delayd(&r, &state->sr1, &sr2);    G726_delayd(&r, &state->sr0, &state->sr1);    G726_delaya(&r, &state->a2r, &a2);    G726_delaya(&r, &state->a1r, &a1);    G726_fmult(&a2, &sr2, &wa2);    G726_fmult(&a1, &state->sr1, &wa1);    G726_delayd(&r, &state->dq5, &dq6);    G726_delayd(&r, &state->dq4, &state->dq5);    G726_delayd(&r, &state->dq3, &state->dq4);    G726_delayd(&r, &state->dq2, &state->dq3);    G726_delayd(&r, &state->dq1, &state->dq2);    G726_delayd(&r, &state->dq0, &state->dq1);    G726_delaya(&r, &state->b1r, &b1);    G726_delaya(&r, &state->b2r, &b2);    G726_delaya(&r, &state->b3r, &b3);    G726_delaya(&r, &state->b4r, &b4);    G726_delaya(&r, &state->b5r, &b5);    G726_delaya(&r, &state->b6r, &b6);    G726_fmult(&b1, &state->dq1, &wb1);    G726_fmult(&b2, &state->dq2, &wb2);    G726_fmult(&b3, &state->dq3, &wb3);    G726_fmult(&b4, &state->dq4, &wb4);    G726_fmult(&b5, &state->dq5, &wb5);    G726_fmult(&b6, &dq6, &wb6);    G726_accum(&wa1, &wa2, &wb1, &wb2, &wb3, &wb4, &wb5, &wb6, &se, &sez);    /* Process delays and `know-state' part of 4.2.5 */    G726_delaya(&r, &state->dmsp, &dms);    G726_delaya(&r, &state->dmlp, &dml);    G726_delaya(&r, &state->apr, &ap);    G726_lima(&ap, &al);    /* Process `know-state' parts of 4.2.4 */    G726_delayb(&r, &state->yup, &yu);    G726_delayc(&r, &state->ylp, &yl);    G726_mix(&al, &yu, &yl, &y);    /* Retrieve ADPCM sample from input buffer */    i = inp_buf[j];    /* Process 4.2.3 */    G726_reconst(rate, &i, &dqln, &dqs);    G726_adda(&dqln, &y, &dql);    G726_antilog(&dql, &dqs, &dq);    /* Process `known-state' part of 4.2.7 */    G726_delaya(&r, &state->tdr, &td);    G726_trans(&td, &yl, &dq, &tr);    /* Part of 4.2.5 */    G726_functf(rate, &i, &fi);    G726_filta(&fi, &dms, &state->dmsp);    G726_filtb(&fi, &dml, &state->dmlp);    /* Remaining part of 4.2.4 */    G726_functw(rate, &i, &wi);    G726_filtd(&wi, &y, &yut);    G726_limb(&yut, &state->yup);    G726_filte(&state->yup, &yl, &state->ylp);    /* More `known-state' parts of 4.2.6: update of `pk's */    G726_delaya(&r, &state->pk1, &pk2);