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libgsmhr1 RxFE: store CN R0+LPC separately from speech In the original GSM 06.06 code the ECU for speech mode is entirely separate from the CN generator, maintaining separate state. (The main intertie between them is the speech vs CN state variable, distinguishing between speech and CN BFIs, in addition to the CN-specific function of distinguishing between initial and update SIDs.) In the present RxFE implementation I initially thought that we could use the same saved_frame buffer for both ECU and CN, overwriting just the first 4 params (R0 and LPC) when a valid SID comes in. However, I now realize it was a bad idea: the original code has a corner case (long sequence of speech-mode BFIs to put the ECU in state 6, then SID and CN-mode BFIs, then a good speech frame) that would be broken by that buffer reuse approach. We could eliminate this corner case by resetting the ECU state when passing through a CN insertion period, but doing so would needlessly increase the behavioral diffs between GSM 06.06 and our version. Solution: use a separate CN-specific buffer for CN R0+LPC parameters, and match the behavior of GSM 06.06 code in this regard.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 13 Feb 2025 10:02:45 +0000
parents 9cca139a20a8
children
line wrap: on
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/*
*****************************************************************************
*
*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
*                                R99   Version 3.3.0                
*                                REL-4 Version 4.1.0                
*
****************************************************************************
*
*      File             : q_plsf_3.c
*      Purpose          : Quantization of LSF parameters with 1st order MA
*                         prediction and split by 3 vector quantization
*                         (split-VQ)
*
*****************************************************************************
*/

/*
*****************************************************************************
*                         MODULE INCLUDE FILE AND VERSION ID
*****************************************************************************
*/
#include "namespace.h"
#include "q_plsf.h"
 
/*
*****************************************************************************
*                         INCLUDE FILES
*****************************************************************************
*/
#include "typedef.h"
#include "basic_op.h"
#include "no_count.h"
#include "lsp_lsf.h"
#include "reorder.h"
#include "lsfwt.h"
#include "memops.h"
#include "q_plsf3_tab.h"

/*
*****************************************************************************
*                         LOCAL VARIABLES AND TABLES
*****************************************************************************
*/
#define PAST_RQ_INIT_SIZE 8
/*
*****************************************************************************
*                         LOCAL PROGRAM CODE
*****************************************************************************
*/
/* Quantization of a 4 dimensional subvector */

static Word16
Vq_subvec4(                   /* o: quantization index,            Q0  */
    Word16 * lsf_r1,          /* i/o: 1st LSF residual vector,     Q15 */
    const Word16 * dico,      /* i: quantization codebook,         Q15 */
    const Word16 * wf1,       /* i: 1st LSF weighting factors,     Q13 */
    Word16 dico_size)         /* i: size of quantization codebook, Q0  */  
{
    Word16 i, index = 0, temp;
    const Word16 *p_dico;
    Word32 dist_min, dist;

    dist_min = MAX_32;                                              move32 ();
    p_dico = dico;                                                  move16 ();

    for (i = 0; i < dico_size; i++)
    {
        temp = sub (lsf_r1[0], *p_dico++);
        temp = mult (wf1[0], temp);
        dist = L_mult (temp, temp);

        temp = sub (lsf_r1[1], *p_dico++);
        temp = mult (wf1[1], temp);
        dist = L_mac (dist, temp, temp);

        temp = sub (lsf_r1[2], *p_dico++);
        temp = mult (wf1[2], temp);
        dist = L_mac (dist, temp, temp);

        temp = sub (lsf_r1[3], *p_dico++);
        temp = mult (wf1[3], temp);
        dist = L_mac (dist, temp, temp);

        test ();
	if (L_sub (dist, dist_min) < (Word32) 0)
        {
            dist_min = dist;                                       move32 ();
            index = i;                                             move16 ();
        }
    }

    /* Reading the selected vector */

    p_dico = &dico[shl (index, 2)];                                move16 ();
    lsf_r1[0] = *p_dico++;                                         move16 ();
    lsf_r1[1] = *p_dico++;                                         move16 ();
    lsf_r1[2] = *p_dico++;                                         move16 ();
    lsf_r1[3] = *p_dico++;                                         move16 ();

    return index;
}

/* Quantization of a 3 dimensional subvector */

static Word16
Vq_subvec3(                   /* o: quantization index,            Q0  */
    Word16 * lsf_r1,          /* i/o: 1st LSF residual vector,     Q15 */
    const Word16 * dico,      /* i: quantization codebook,         Q15 */
    const Word16 * wf1,       /* i: 1st LSF weighting factors,     Q13 */
    Word16 dico_size,         /* i: size of quantization codebook, Q0  */
    Flag use_half)            /* i: use every second entry in codebook */
{
    Word16 i, index = 0, temp;
    const Word16 *p_dico;
    Word32 dist_min, dist;

    dist_min = MAX_32;                                             move32 ();
    p_dico = dico;                                                 move16 ();

    test ();
    if (use_half == 0) {
       for (i = 0; i < dico_size; i++)
       {
          temp = sub(lsf_r1[0], *p_dico++);
          temp = mult(wf1[0], temp);
          dist = L_mult(temp, temp);
          
          temp = sub(lsf_r1[1], *p_dico++);
          temp = mult(wf1[1], temp);
          dist = L_mac(dist, temp, temp);
          
          temp = sub(lsf_r1[2], *p_dico++);
          temp = mult(wf1[2], temp);
          dist = L_mac(dist, temp, temp);

          test ();
          if (L_sub(dist, dist_min) < (Word32) 0) {
             dist_min = dist;                                   move32 ();
             index = i;                                         move16 ();
          }
       }
       p_dico = &dico[add(index, add(index, index))];             move16 ();
    }
    else
    {
       for (i = 0; i < dico_size; i++)
       {
          temp = sub(lsf_r1[0], *p_dico++);
          temp = mult(wf1[0], temp);
          dist = L_mult(temp, temp);

          temp = sub(lsf_r1[1], *p_dico++);
          temp = mult(wf1[1], temp);
          dist = L_mac(dist, temp, temp);
          
          temp = sub(lsf_r1[2], *p_dico++);
          temp = mult(wf1[2], temp);
          dist = L_mac(dist, temp, temp);
          
          test ();
          if (L_sub(dist, dist_min) < (Word32) 0)
          {
             dist_min = dist;                                   move32 ();
             index = i;                                         move16 ();
          }
          p_dico = p_dico + 3; add(0,0);
       }
       p_dico = &dico[shl(add(index, add(index, index)),1)];      move16 ();
    }

    /* Reading the selected vector */
    lsf_r1[0] = *p_dico++;                                         move16 ();
    lsf_r1[1] = *p_dico++;                                         move16 ();
    lsf_r1[2] = *p_dico++;                                         move16 ();

    return index;
}

/*
*****************************************************************************
*                         PUBLIC PROGRAM CODE
*****************************************************************************
*/

/***********************************************************************
 *
 * routine:   Q_plsf_3()
 *
 * Quantization of LSF parameters with 1st order MA prediction and
 * split by 3 vector quantization (split-VQ)
 *
 ***********************************************************************/
void Q_plsf_3(
    Q_plsfState *st,    /* i/o: state struct                             */
    enum Mode mode,     /* i  : coder mode                               */
    Word16 *lsp1,       /* i  : 1st LSP vector                      Q15  */
    Word16 *lsp1_q,     /* o  : quantized 1st LSP vector            Q15  */
    Word16 *indice,     /* o  : quantization indices of 3 vectors   Q0   */
    Word16 *pred_init_i /* o  : init index for MA prediction in DTX mode */
)
{
    Word16 i, j;
    Word16 lsf1[M], wf1[M], lsf_p[M], lsf_r1[M];
    Word16 lsf1_q[M];
    
    Word32 L_pred_init_err;
    Word32 L_min_pred_init_err;
    Word16 temp_r1[M];
    Word16 temp_p[M];

    /* convert LSFs to normalize frequency domain 0..16384 */

    Lsp_lsf(lsp1, lsf1, M);

    /* compute LSF weighting factors (Q13) */

    Lsf_wt(lsf1, wf1);

    /* Compute predicted LSF and prediction error */
    if (test(), sub(mode, MRDTX) != 0)
    {
       for (i = 0; i < M; i++)
       {
          lsf_p[i] = add(mean_lsf3[i], 
                         mult(st->past_rq[i], 
                              pred_fac[i]));                            move16 ();
          lsf_r1[i] = sub(lsf1[i], lsf_p[i]);                           move16 ();
      }
    }
    else
    {
       /* DTX mode, search the init vector that yields */
       /* lowest prediction resuidual energy           */
       *pred_init_i = 0;                                                move16 ();
       L_min_pred_init_err = 0x7fffffff; /* 2^31 - 1 */                 move32 ();
       for (j = 0; j < PAST_RQ_INIT_SIZE; j++)
       {
          L_pred_init_err = 0;                                          move32 ();
          for (i = 0; i < M; i++)
          {
             temp_p[i] = add(mean_lsf3[i], past_rq_init[j*M+i]);
             temp_r1[i] = sub(lsf1[i],temp_p[i]);
             L_pred_init_err = L_mac(L_pred_init_err, temp_r1[i], temp_r1[i]);
          }  /* next i */

          test ();
          if (L_sub(L_pred_init_err, L_min_pred_init_err) < (Word32) 0)
          {
             L_min_pred_init_err = L_pred_init_err;                     move32 (); 
             Copy(temp_r1, lsf_r1, M);
             Copy(temp_p, lsf_p, M);
             
             /* Set zerom */
             Copy(&past_rq_init[j*M], st->past_rq, M);
             *pred_init_i = j;                                          move16 ();            
          } /* endif */
       } /* next j */
    } /* endif MRDTX */
    
    /*---- Split-VQ of prediction error ----*/
    if (sub (mode, MR475) == 0 || sub (mode, MR515) == 0)
    {   /* MR475, MR515 */
      test (); test (); 
                          
      indice[0] = Vq_subvec3(&lsf_r1[0], dico1_lsf3, &wf1[0], DICO31_SIZE, 0);
      move16 ();
      indice[1] = Vq_subvec3(&lsf_r1[3], dico2_lsf3, &wf1[3], DICO32_SIZE/2, 1);
      move16 ();
      indice[2] = Vq_subvec4(&lsf_r1[6], mr515_3_lsf, &wf1[6], MR515_3_SIZE);
      move16 ();
    }
    else if (sub (mode, MR795) == 0)
    {   /* MR795 */
      test (); test (); test ();
       
      indice[0] = Vq_subvec3(&lsf_r1[0], mr795_1_lsf, &wf1[0], MR795_1_SIZE, 0);
      move16 ();
      indice[1] = Vq_subvec3(&lsf_r1[3], dico2_lsf3, &wf1[3], DICO32_SIZE, 0);
      move16 ();
      indice[2] = Vq_subvec4(&lsf_r1[6], dico3_lsf3, &wf1[6], DICO33_SIZE);
      move16 ();
    }
    else 
    {   /* MR59, MR67, MR74, MR102 , MRDTX */
      test (); test (); test ();

      indice[0] = Vq_subvec3(&lsf_r1[0], dico1_lsf3, &wf1[0], DICO31_SIZE, 0);
      move16 ();
      indice[1] = Vq_subvec3(&lsf_r1[3], dico2_lsf3, &wf1[3], DICO32_SIZE, 0);
      move16 ();
      indice[2] = Vq_subvec4(&lsf_r1[6], dico3_lsf3, &wf1[6], DICO33_SIZE);
      move16 ();
    }

        
    /* Compute quantized LSFs and update the past quantized residual */

    for (i = 0; i < M; i++)
    {
        lsf1_q[i] = add(lsf_r1[i], lsf_p[i]);                        move16 ();
        st->past_rq[i] = lsf_r1[i];                                  move16 ();
    }

    /* verification that LSFs has mimimum distance of LSF_GAP Hz */

    Reorder_lsf(lsf1_q, LSF_GAP, M);

    /*  convert LSFs to the cosine domain */

    Lsf_lsp(lsf1_q, lsp1_q, M);
}