www.pudn.com > AVS_M_ver10.rar > isp_isf.c

/* 
*********************************************************************** 
* COPYRIGHT AND WARRANTY INFORMATION 
* 
* Copyright 2007  Audio Video Coding Standard, Part ¢ú 
* 
* This software module was developed by AVS Audio sub-group 
* 
* DISCLAIMER OF WARRANTY 
* 
* These software programs are available to the users without any 
* license fee or royalty on an "as is" basis. The AVS disclaims 
* any and all warranties, whether express, implied, or statutory, 
* including any implied warranties of merchantability or of fitness 
* for a particular purpose. In no event shall the contributors or  
* the AVS be liable for any incidental, punitive, or consequential 
* damages of any kind whatsoever arising from the use of this program. 
* 
* This disclaimer of warranty extends to the user of this program 
* and user's customers, employees, agents, transferees, successors, 
* and assigns. 
* 
* The AVS does not represent or warrant that the program furnished 
* hereunder are free of infringement of any third-party patents. 
* Commercial implementations of AVS, including shareware, may be 
* subject to royalty fees to patent holders. Information regarding 
* the AVS patent policy is available from the AVS Web site at 
* http://www.avs.org.cn 
* 
* THIS IS NOT A GRANT OF PATENT RIGHTS - SEE THE AVS PATENT POLICY. 
************************************************************************ 
*/ 
 
/*-----------------------------------------------------------------------* 
 *   Functions : isp2isf and isf2isp                                     * 
 *                                                                       * 
 *      isp2isf   Transformation isp to isf                              * 
 *      isf2isp   Transformation isf to isp                              * 
 *                                                                       * 
 *   ISP are immitance spectral pair in cosine domain (-1 to 1).         * 
 *   ISF are immitance spectral pair in frequency domain (0 to 6400).    * 
 *-----------------------------------------------------------------------*/ 
#include  
#include  
#include "../include/amr_plus.h" 
#define SCALE1  (6400.0/PI) 
#define SCALE2  (PI/6400.0) 
#ifndef PI 
#define PI      3.141592654 
#endif 
void isf2isp( 
  float isf[],    /* input : isf[m] normalized (range: 0<=val<=6400)  */ 
  float isp[],    /* output: isp[m] (range: -1<=val<1)                */ 
  int   m         /* input : LPC order                                */ 
) 
{ 
  int i; 
  /*  convert ISFs to the cosine domain */ 
  for(i=0; i