cod_ld8a.c

语音编码G.729 语音编码G.729

/*
   ITU-T G.729 Annex C - Reference C code for floating point
                         implementation of G.729 Annex A
                         Version 1.01 of 15.September.98
*/

/*
----------------------------------------------------------------------
                    COPYRIGHT NOTICE
----------------------------------------------------------------------
   ITU-T G.729 Annex C ANSI C source code
   Copyright (C) 1998, AT&T, France Telecom, NTT, University of
   Sherbrooke.  All rights reserved.

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

/*
 File : COD_LD8A.C
 Used for the floating point version of G.729A only
 (not for G.729 main body)
*/

/*-----------------------------------------------------------------*
 *   Functions coder_ld8a and init_coder_ld8a                      *
 *             ~~~~~~~~~~     ~~~~~~~~~~~~~~~                      *
 *                                                                 *
 *  init_coder_ld8a(void);                                         *
 *                                                                 *
 *   ->Initialization of variables for the coder section.          *
 *                                                                 *
 *                                                                 *
 *  coder_ld8a(Short ana[]);                                       *
 *                                                                 *
 *   ->Main coder function.                                        *
 *                                                                 *
 *                                                                 *
 *  Input:                                                         *
 *                                                                 *
 *    80 speech data should have beee copy to vector new_speech[]. *
 *    This vector is global and is declared in this function.      *
 *                                                                 *
 *  Ouputs:                                                        *
 *                                                                 *
 *    ana[]      ->analysis parameters.                            *
 *                                                                 *
 *-----------------------------------------------------------------*/

#include <math.h>
#include "typedef.h"
#include "ld8a.h"
#include "cst_ld8a.h"
#include "tab_ld8a.h"

/*-----------------------------------------------------------*
 *    Coder constant parameters (defined in "ld8a.h")        *
 *-----------------------------------------------------------*
 *   L_WINDOW    : LPC analysis window size.                 *
 *   L_NEXT      : Samples of next frame needed for autocor. *
 *   L_FRAME     : Frame size.                               *
 *   L_SUBFR     : Sub-frame size.                           *
 *   M           : LPC order.                                *
 *   MP1         : LPC order+1                               *
 *   L_TOTAL     : Total size of speech buffer.              *
 *   PIT_MIN     : Minimum pitch lag.                        *
 *   PIT_MAX     : Maximum pitch lag.                        *
 *   L_INTERPOL  : Length of filter for interpolation        *
 *-----------------------------------------------------------*/

/*-----------------------------------------------------------------*
 *   Function  init_coder_ld8a                                     *
 *            ~~~~~~~~~~~~~~~                                      *
 *                                                                 *
 *  init_coder_ld8a(void);                                         *
 *                                                                 *
 *   ->Initialization of variables for the coder section.          *
 *       - initialize pointers to speech buffer                    *
 *       - initialize static  pointers                             *
 *       - set static vectors to zero                              *
 *-----------------------------------------------------------------*/

void init_coder_ld8a(struct cod_state_t * state)
{

  /*----------------------------------------------------------------------*
  *      Initialize pointers to speech vector.                            *
  *                                                                       *
  *                                                                       *
  *   |--------------------|-------------|-------------|------------|     *
  *     previous speech           sf1           sf2         L_NEXT        *
  *                                                                       *
  *   <----------------  Total speech vector (L_TOTAL)   ----------->     *
  *   <----------------  LPC analysis window (L_WINDOW)  ----------->     *
  *   |                   <-- present frame (L_FRAME) -->                 *
  * old_speech            |              <-- new speech (L_FRAME) -->     *
  * p_window              |              |                                *
  *                     speech           |                                *
  *                             new_speech                                *
  *-----------------------------------------------------------------------*/

	state->new_speech = state->old_speech + L_TOTAL - L_FRAME;         /* New speech     */
	state->speech     = state->new_speech - L_NEXT;                    /* Present frame  */
	state->p_window   = state->old_speech + L_TOTAL - L_WINDOW;        /* For LPC window */

	/* Initialize static pointers */

	state->wsp    = state->old_wsp + PIT_MAX;
	state->exc    = state->old_exc + PIT_MAX + L_INTERPOL;

	/* Static vectors to zero */

	set_zero(state->old_speech, L_TOTAL);
	set_zero(state->old_exc, PIT_MAX+L_INTERPOL);
	set_zero(state->old_wsp, PIT_MAX);
	set_zero(state->mem_w,   M);
	set_zero(state->mem_w0,  M);
	set_zero(state->mem_zero, M);
	state->sharp = SHARPMIN;

	copy(lsp_reset, state->lsp_old, M);
	copy(state->lsp_old, state->lsp_old_q, M);
	lsp_codw_reset(&state->lsp_s);

	init_exc_err(state->cng_s.exc_err); // ?

	/* For G.729B */
	/* Initialize VAD/DTX parameters */
	state->pastVad = 1;
	state->ppastVad = 1;
	state->seed = INIT_SEED;
	vad_init(&state->vad_s);

	init_lsfq_noise(&state->cng_s.lsfq_s); // ?

	gain_past_reset(&state->gain_s);
}

/*-----------------------------------------------------------------*
 *   Function coder_ld8a                                           *
 *            ~~~~~~~~~~                                           *
 *  coder_ld8a(int    ana[]);                                      *
 *                                                                 *
 *   ->Main coder function.                                        *
 *                                                                 *
 *                                                                 *
 *  Input:                                                         *
 *                                                                 *
 *    80 speech data should have beee copy to vector new_speech[]. *
 *    This vector is global and is declared in this function.      *
 *                                                                 *
 *  Ouputs:                                                        *
 *                                                                 *
 *    ana[]      ->analysis parameters.                            *
 *                                                                 *
 *-----------------------------------------------------------------*/

void coder_ld8a(struct cod_state_t * state,
  int ana[],        /* output: analysis parameters */
  int frame,        /* input   : frame counter       */
  int vad_enable    /* input   : VAD enable flag     */
)
{
   /* LPC coefficients */

   FLOAT Aq_t[(MP1)*2];         /* A(z) quantized for the 2 subframes   */
   FLOAT Ap_t[(MP1)*2];         /* A(z) with spectral expansion         */
   FLOAT *Aq, *Ap;              /* Pointer on Aq_t  and Ap_t            */

   /* Other vectors */

   FLOAT h1[L_SUBFR];           /* Impulse response h1[]              */
   FLOAT xn[L_SUBFR];           /* Target vector for pitch search     */
   FLOAT xn2[L_SUBFR];          /* Target vector for codebook search  */
   FLOAT code[L_SUBFR];         /* Fixed codebook excitation          */
   FLOAT y1[L_SUBFR];           /* Filtered adaptive excitation       */
   FLOAT y2[L_SUBFR];           /* Filtered fixed codebook excitation */
   FLOAT g_coeff[5];            /* Correlations between xn, y1, & y2:
                                   <y1,y1>, <xn,y1>, <y2,y2>, <xn,y2>,<y1,y2>*/

   /* Scalars */

   int i, j, i_subfr;
   int T_op, T0, T0_min, T0_max, T0_frac;
   int index;
   FLOAT   gain_pit, gain_code;
   int     taming;

/*------------------------------------------------------------------------*
 *  - Perform LPC analysis:                                               *
 *       * autocorrelation + lag windowing                                *
 *       * Levinson-durbin algorithm to find a[]                          *
 *       * convert a[] to lsp[]                                           *
 *       * quantize and code the LSPs                                     *
 *       * find the interpolated LSPs and convert to a[] for the 2        *
 *         subframes (both quantized and unquantized)                     *
 *------------------------------------------------------------------------*/
   {
      /* Temporary vectors */
     FLOAT r[NP+1];                   /* Autocorrelations       */
     FLOAT rc[M];                     /* Reflexion coefficients */
     FLOAT lsp_new[M];                /* lsp coefficients       */
     FLOAT lsp_new_q[M];              /* Quantized lsp coeff.   */
	 FLOAT lsf_new[M];
 
	 /* For G.729B */
     FLOAT r_nbe[MP1];
     FLOAT lsfq_mem[MA_NP][M];
     int Vad;
     FLOAT Energy_db;

     /* LP analysis */
     autocorr(state->p_window, NP, r);        /* Autocorrelations */
     copy(r, r_nbe, MP1);
     lag_window(NP, r);                       /* Lag windowing    */
     levinson(r, Ap_t, rc);                   /* Levinson Durbin  */
     az_lsp(Ap_t, lsp_new, state->lsp_old);   /* Convert A(z) to lsp */

	/* For G.729B */
	/* ------ VAD ------- */
	if (vad_enable)
	{
		lsp_lsf(lsp_new, lsf_new, M);
		vad(&state->vad_s, rc[1], lsf_new, r, state->p_window, frame,
			state->pastVad, state->ppastVad, &Vad, &Energy_db);

		update_cng(&state->cng_s, r_nbe, Vad);
	}
	else
		Vad = 1;


	/* ---------------------- */
	/* Case of Inactive frame */
	/* ---------------------- */

	if (!Vad)
	{
	  get_freq_prev((const FLOAT (*)[M]) state->lsp_s.freq_prev, lsfq_mem);
	  cod_cng(&state->cng_s, state->exc, state->pastVad, state->lsp_old_q, Aq_t, ana, lsfq_mem, &state->seed);