ntt_denormalizer_spectrum.c

语音压缩算法

/*****************************************************************************/
/* This software module was originally developed by                          */
/*   Naoki Iwakami (NTT)                                                     */
/* and edited by                                                             */
/*   Naoki Iwakami and Satoshi Miki (NTT) on 1996-05-01,                     */
/*   Naoki Iwakami (NTT) on 1996-08-27,                                      */
/*   Naoki Iwakami (NTT) on 1997-04-18,                                      */
/* in the course of development of the                                       */
/* MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and 3.        */
/* This software module is an implementation of a part of one or more        */
/* MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 Audio */
/* standard. ISO/IEC  gives users of the MPEG-2 NBC/MPEG-4 Audio standards   */
/* free license to this software module or modifications thereof for use in  */
/* hardware or software products claiming conformance to the MPEG-2 NBC/     */
/* MPEG-4 Audio  standards. Those intending to use this software module in   */
/* hardware or software products are advised that this 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-2 NBC/MPEG-4 Audio conforming products. The original developer       */
/* 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 party from using    */
/* the code for non MPEG-2 NBC/MPEG-4 Audio conforming products.             */
/* This copyright notice must be included in all copies or derivative works. */
/* Copyright (c)1996.                                                        */
/*****************************************************************************/

/* 18-apr-97 NI merged long, medium, & short procedure into single module */

#include <stdio.h>

#include "block.h"               /* handler, defines, enums */
#include "buffersHandle.h"       /* handler, defines, enums */
#include "interface.h"           /* handler, defines, enums */
#include "mod_bufHandle.h"       /* handler, defines, enums */
#include "resilienceHandle.h"    /* handler, defines, enums */
#include "tf_mainHandle.h"       /* handler, defines, enums */

#include "nok_ltp_common.h"      /* structs */
#include "tf_mainStruct.h"       /* structs */
#include "tns.h"                 /* structs */
#include "ntt_conf.h"

void ntt_denormalizer_spectrum(/* Parameters */
			       int    nfr,
			       int    nsf,
			       int    n_ch,
			       /* Input */
			       double flat_spectrum[],
			       double gain[],
			       /*****/
			       double pit_sec[],
			       double pgain[],
			       /*****/
			       double bark_env[],
			       double inv_lpc_spec[], /**** inv */
			       /* Output */
			       double spectrum[])
{
  /*--- Variables ---*/
  int    ismp, isf, i_ch;
  int    top, subtop;
  double dtemp;
  
  /*--- Decoding process ---*/
  for (i_ch=0; i_ch<n_ch; i_ch++){
    top = i_ch * nfr * nsf;
    for (isf=0; isf<nsf; isf++){
      subtop = isf * nfr;
      for (ismp=0; ismp<nfr; ismp++){
	dtemp = pgain[isf+i_ch*nsf] * pit_sec[ismp+top+subtop]; 
	spectrum[ismp + top + subtop]
	  = (gain[isf+i_ch*nsf] * flat_spectrum[ismp+top+subtop]
	     * bark_env[ismp + top + subtop] + dtemp)
	    * inv_lpc_spec[ismp + i_ch*nfr];
      }
    }
  }
}