phi_axit.c

MPEG2/MPEG4编解码参考程序(实现了MPEG4的部分功能)

/*====================================================================*/
/*         MPEG-4 Audio (ISO/IEC 14496-3) Copyright Header            */
/*====================================================================*/
/*
This software module was originally developed by Rakesh Taori and Andy
Gerrits (Philips Research Laboratories, Eindhoven, The Netherlands) in
the course of development of the MPEG-4 Audio (ISO/IEC 14496-3). This
software module is an implementation of a part of one or more MPEG-4
Audio (ISO/IEC 14496-3) tools as specified by the MPEG-4 Audio
(ISO/IEC 14496-3). ISO/IEC gives users of the MPEG-4 Audio (ISO/IEC
14496-3) free license to this software module or modifications thereof
for use in hardware or software products claiming conformance to the
MPEG-4 Audio (ISO/IEC 14496-3). Those intending to use this software
module in hardware or software products are advised that its use may
infringe existing patents. The original developer of this software
module and his/her company, the subsequent editors and their
companies, and ISO/IEC have no liability for use of this software
module or modifications thereof in an implementation. Copyright is not
released for non MPEG-4 Audio (ISO/IEC 14496-3) conforming products.
CN1 retains full right to use the code for his/her own purpose, assign
or donate the code to a third party and to inhibit third parties from
using the code for non MPEG-4 Audio (ISO/IEC 14496-3) conforming
products.  This copyright notice must be included in all copies or
derivative works. Copyright 1996.
*/
/*====================================================================*/
/*======================================================================*/
/*                                                                      */
/*      SOURCE_FILE:    PHI_AXIT.C                                      */
/*      PACKAGE:        WDBxx                                           */
/*      COMPONENT:      Excitation Analysis Modules                     */
/*                                                                      */
/*======================================================================*/

/*======================================================================*/
/*      I N C L U D E S                                                 */
/*======================================================================*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <malloc.h> 
#include <float.h>
#include <assert.h>  

#include "buffersHandle.h"       /* handler, defines, enums */

#include "lpc_common.h"               /* Prototype definitions          */      
#include "phi_cons.h"                 /* Prototype definitions          */      
#include "phi_apre.h"                 /* Prototype definitions          */      
#include "phi_xits.h"                 /* Prototype definitions          */      
#include "phi_axit.h"                 /* Prototype definitions          */      

/*======================================================================*/
/*       L O C A L    D A T A   D E C L A R A T I O N                   */
/*======================================================================*/
static float *PHI_s_state;     /* Synthesis filter states during search */
static float *PHI_Wden_states; /* Synthesis filter states for decoder   */
static float *PHI_cba_codebook;/* Adaptive Codebook                     */
static float PHI_afp = (float)0.0;/* First-order LPC parameter(previous)*/
static long  PHI_sbfrm_ctr = 0;/* Local counter: current subframe       */ 
static long  PHI_D;
static long  PHI_Np;
static long  PHI_Nz;
static long  PHI_Nf;

/*======================================================================*/
/* Function Definition: PHI_init_excitation_analysis                    */
/*======================================================================*/
void 
PHI_init_excitation_analysis
(
const long max_lag,   /* In:Maximum permitted lag in the adaptive cbk */ 
const long lpc_order, /* In:The LPC order                             */
const long sbfrm_size,/* In:Size of subframe in samples               */
const long RPE_configuration /* In:Confguration                        */
)
{
    int i;
 
    /* -----------------------------------------------------------------*/
    /* Allocate memory for the local-decoder synthesis filter-states    */
    /* -----------------------------------------------------------------*/
    if(( PHI_s_state = (float *)malloc((unsigned int)lpc_order * sizeof(float))) == NULL )
    {
        printf("MALLOC FAILURE in init_abs_excitation_analysis \n");
        exit(1);
    }
    
    /* -----------------------------------------------------------------*/
    /* Allocate memory for the encoder perceptual wighting filter-states*/
    /* -----------------------------------------------------------------*/
    if(( PHI_Wden_states = (float *)malloc((unsigned int)lpc_order * sizeof(float))) == NULL )
    {
        printf("MALLOC FAILURE in init_abs_excitation_analysis \n");
        exit(1);
    }
    
    /* -----------------------------------------------------------------*/
    /* Allocate memory for the adaptive Codebook                        */
    /* -----------------------------------------------------------------*/
    if(( PHI_cba_codebook = (float *)malloc((unsigned int)max_lag * sizeof(float))) == NULL )
    {
        printf("MALLOC FAILURE in init_abs_excitation_analysis \n");
        exit(1);
    }
    
    /* -----------------------------------------------------------------*/
    /* Initialise the adaptive codebook                                 */
    /* -----------------------------------------------------------------*/
    for (i = 0; i < (int)max_lag; i ++)
    {
        PHI_cba_codebook[i] = (float)0.0;
    }

    /* -----------------------------------------------------------------*/
    /* Initialise the filter states                                     */
    /* -----------------------------------------------------------------*/
    for (i = 0; i < (int)lpc_order; i ++)
    {
        PHI_s_state[i]  = PHI_Wden_states[i] = (float)0.0;
    }
    
    /* -----------------------------------------------------------------*/
    /* Set the excitation Parameters                                    */
    /* -----------------------------------------------------------------*/
    
    PHI_D = 1;
    if ((RPE_configuration == 0) || (RPE_configuration == 1))
    {
         PHI_D = 8;
    }

    if (RPE_configuration == 2)
    {
         PHI_D = 5;
    }

    if (RPE_configuration == 3)
    {
         PHI_D = 4;
    }
    
    PHI_Np = sbfrm_size/PHI_D;
    PHI_Nz = PHI_Np - 4;
    PHI_Nf = (long)1 << (PHI_Np - PHI_Nz);
    if (PHI_Nf != 16)
    {
         fprintf(stderr, "ERROR:Incorrect parameters in excitation analysis \n");
         exit(1);
    }
}


/*======================================================================*/
/* Function Definition: celp_excitation_analysis                        */
/*======================================================================*/
void celp_excitation_analysis
(
                                  /* -----------------------------------*/
                                  /* INPUT PARAMETERS                   */
                                  /* -----------------------------------*/
float PP_InputSignal[],           /* Preprocessed Input signal          */
float lpc_residual[],             /* Inverse Filtered Signal            */
float int_Qlpc_coefficients[],    /* Interpolated LPC Coeffs            */
long  lpc_order,                  /* Order of LPC                       */        
float Wnum_coeff[],               /* Weighting Filter: Numerator        */
float Wden_coeff[],               /* Weighting Filter: Denominator      */
float first_order_lpc_par,        /* apar corresponding to 1st-order fit*/
long  lag_candidates[],           /* Array of Lag candidates            */
long  n_lag_candidates,           /* Number of lag candidates           */
long  frame_size,                 /* Number of samples in the frame     */
long  sbfrm_size,                 /* Number of samples in the subframe  */
long  n_subframes,                /* Number of subframes                */
long  signal_mode,                /* Configuration Input                */
long  frame_bit_allocation[],     /* Configuration Input                */
                                  /* -----------------------------------*/
                                  /* OUTPUT PARAMETERS                  */
                                  /* -----------------------------------*/
long  shape_indices[],            /* Adaptive and Fixed codebook lags   */
long  gain_indices[],             /* Adaptive and Fixed codebook gains  */
long  num_shape_cbks,             /* Number of shape codebooks          */
long  num_gain_cbks,              /* Number of gain codebooks           */
long  *rms_index,                 /* RMS Value ????                     */
float decoded_excitation[]        /* Synthesised Signal                 */
)
{
    /*==================================================================*/
    /*  Volatile Variables for this subroutine                          */
    /*==================================================================*/
    long  *amp;         /* Amplitude Array for the RPE sequence         */
    long  *pos;         /* Position of fixed amplitude in RPE codebook  */