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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 128ec87489b6
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_5.c
*      Purpose          : Quantization of 2 sets of LSF parameters using 1st 
*                         order MA prediction and split by 5 matrix
*                         quantization (split-MQ)
*
********************************************************************************
*/
 
/*
********************************************************************************
*                         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 "q_plsf5_tab.h"

/*
********************************************************************************
*                         LOCAL PROGRAM CODE
********************************************************************************
*/
/* Quantization of a 4 dimensional subvector */

static Word16 Vq_subvec (/* o : quantization index,            Q0  */
    Word16 *lsf_r1,      /* i : 1st LSF residual vector,       Q15 */
    Word16 *lsf_r2,      /* i : 2nd LSF residual vector,       Q15 */
    const Word16 *dico,  /* i : quantization codebook,         Q15 */
    Word16 *wf1,         /* i : 1st LSF weighting factors      Q13 */
    Word16 *wf2,         /* i : 2nd LSF weighting factors      Q13 */  
    Word16 dico_size     /* i : size of quantization codebook, Q0  */
)
{
    Word16 index = 0; /* initialization only needed to keep gcc silent */
    Word16 i, 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_r2[0], *p_dico++);
        temp = mult (wf2[0], temp);
        dist = L_mac (dist, temp, temp);

        temp = sub (lsf_r2[1], *p_dico++);
        temp = mult (wf2[1], 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_r2[0] = *p_dico++;                              move16 (); 
    lsf_r2[1] = *p_dico++;                              move16 (); 

    return index;
}

/* Quantization of a 4 dimensional subvector with a signed codebook */

static Word16 Vq_subvec_s ( /* o : quantization index            Q0  */
    Word16 *lsf_r1,         /* i : 1st LSF residual vector       Q15 */
    Word16 *lsf_r2,         /* i : and LSF residual vector       Q15 */
    const Word16 *dico,     /* i : quantization codebook         Q15 */
    Word16 *wf1,            /* i : 1st LSF weighting factors     Q13 */
    Word16 *wf2,            /* i : 2nd LSF weighting factors     Q13 */
    Word16 dico_size)       /* i : size of quantization codebook Q0  */  
{
    Word16 index = 0;  /* initialization only needed to keep gcc silent */
    Word16 sign = 0;   /* initialization only needed to keep gcc silent */
    Word16 i, 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++)
    {
        /* test positive */

        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_r2[0], *p_dico++);
        temp = mult (wf2[0], temp);
        dist = L_mac (dist, temp, temp);

        temp = sub (lsf_r2[1], *p_dico++);
        temp = mult (wf2[1], temp);
        dist = L_mac (dist, temp, temp);

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

        p_dico -= 4;                                    move16 (); 
        temp = add (lsf_r1[0], *p_dico++);
        temp = mult (wf1[0], temp);
        dist = L_mult (temp, temp);

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

        temp = add (lsf_r2[0], *p_dico++);
        temp = mult (wf2[0], temp);
        dist = L_mac (dist, temp, temp);

        temp = add (lsf_r2[1], *p_dico++);
        temp = mult (wf2[1], temp);
        dist = L_mac (dist, temp, temp);

        test (); 
        if (L_sub (dist, dist_min) < (Word32) 0)
        {
            dist_min = dist;                            move32 (); 
            index = i;                                  move16 (); 
            sign = 1;                                   move16 (); 
        }
    }

    /* Reading the selected vector */

    p_dico = &dico[shl (index, 2)];                     move16 (); 
    test (); 
    if (sign == 0)
    {
        lsf_r1[0] = *p_dico++;                          move16 (); 
        lsf_r1[1] = *p_dico++;                          move16 (); 
        lsf_r2[0] = *p_dico++;                          move16 (); 
        lsf_r2[1] = *p_dico++;                          move16 (); 
    }
    else
    {
        lsf_r1[0] = negate (*p_dico++);                 move16 (); 
        lsf_r1[1] = negate (*p_dico++);                 move16 (); 
        lsf_r2[0] = negate (*p_dico++);                 move16 (); 
        lsf_r2[1] = negate (*p_dico++);                 move16 (); 
    }

    index = shl (index, 1);
    index = add (index, sign);

    return index;
}

/*
********************************************************************************
*                         PUBLIC PROGRAM CODE
********************************************************************************
*/
 
/*************************************************************************
 *   FUNCTION:  Q_plsf_5()
 *
 *   PURPOSE:  Quantization of 2 sets of LSF parameters using 1st order MA
 *             prediction and split by 5 matrix quantization (split-MQ)
 *
 *   DESCRIPTION:
 *
 *        p[i] = pred_factor*past_rq[i];   i=0,...,m-1
 *        r1[i]= lsf1[i] - p[i];           i=0,...,m-1
 *        r2[i]= lsf2[i] - p[i];           i=0,...,m-1
 *   where:
 *        lsf1[i]           1st mean-removed LSF vector.
 *        lsf2[i]           2nd mean-removed LSF vector.
 *        r1[i]             1st residual prediction vector.
 *        r2[i]             2nd residual prediction vector.
 *        past_r2q[i]       Past quantized residual (2nd vector).
 *
 *   The residual vectors r1[i] and r2[i] are jointly quantized using
 *   split-MQ with 5 codebooks. Each 4th dimension submatrix contains 2
 *   elements from each residual vector. The 5 submatrices are as follows:
 *     {r1[0], r1[1], r2[0], r2[1]};  {r1[2], r1[3], r2[2], r2[3]};
 *     {r1[4], r1[5], r2[4], r2[5]};  {r1[6], r1[7], r2[6], r2[7]};
 *                    {r1[8], r1[9], r2[8], r2[9]};
 *
 *************************************************************************/
void Q_plsf_5 (
    Q_plsfState *st,
    Word16 *lsp1,      /* i : 1st LSP vector,                     Q15 */
    Word16 *lsp2,      /* i : 2nd LSP vector,                     Q15 */   
    Word16 *lsp1_q,    /* o : quantized 1st LSP vector,           Q15 */
    Word16 *lsp2_q,    /* o : quantized 2nd LSP vector,           Q15 */
    Word16 *indice     /* o : quantization indices of 5 matrices, Q0  */
)
{
    Word16 i;
    Word16 lsf1[M], lsf2[M], wf1[M], wf2[M], lsf_p[M], lsf_r1[M], lsf_r2[M];
    Word16 lsf1_q[M], lsf2_q[M];

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

    Lsp_lsf (lsp1, lsf1, M);
    Lsp_lsf (lsp2, lsf2, M);

    /* Compute LSF weighting factors (Q13) */
    
    Lsf_wt (lsf1, wf1);
    Lsf_wt (lsf2, wf2);

    /* Compute predicted LSF and prediction error */

    for (i = 0; i < M; i++)
    {
        lsf_p[i] = add (mean_lsf[i], mult (st->past_rq[i], LSP_PRED_FAC_MR122));
        move16 (); 
        lsf_r1[i] = sub (lsf1[i], lsf_p[i]);           move16 (); 
        lsf_r2[i] = sub (lsf2[i], lsf_p[i]);           move16 (); 
    }

    /*---- Split-MQ of prediction error ----*/

    indice[0] = Vq_subvec (&lsf_r1[0], &lsf_r2[0], dico1_lsf,
                           &wf1[0], &wf2[0], DICO1_SIZE);
                                                        move16 (); 

    indice[1] = Vq_subvec (&lsf_r1[2], &lsf_r2[2], dico2_lsf,
                           &wf1[2], &wf2[2], DICO2_SIZE);
                                                        move16 (); 

    indice[2] = Vq_subvec_s (&lsf_r1[4], &lsf_r2[4], dico3_lsf,
                             &wf1[4], &wf2[4], DICO3_SIZE);
                                                        move16 (); 

    indice[3] = Vq_subvec (&lsf_r1[6], &lsf_r2[6], dico4_lsf,
                           &wf1[6], &wf2[6], DICO4_SIZE);
                                                        move16 (); 

    indice[4] = Vq_subvec (&lsf_r1[8], &lsf_r2[8], dico5_lsf,
                           &wf1[8], &wf2[8], DICO5_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 (); 
        lsf2_q[i] = add (lsf_r2[i], lsf_p[i]);          move16 (); 
        st->past_rq[i] = lsf_r2[i];                     move16 (); 
    }

    /* verification that LSFs has minimum distance of LSF_GAP */

    Reorder_lsf (lsf1_q, LSF_GAP, M);
    Reorder_lsf (lsf2_q, LSF_GAP, M);

    /*  convert LSFs to the cosine domain */
    
    Lsf_lsp (lsf1_q, lsp1_q, M);
    Lsf_lsp (lsf2_q, lsp2_q, M);
}