www.pudn.com > AVS_M_ver10.rar > pit_fr4.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. 
************************************************************************ 
*/ 
 
/*-------------------------------------------------------------------* 
 * procedure pitch_fr4                                               * 
 * ~~~~~~~~~~~~~~~~~~~                                               * 
 * Find the closed loop pitch period with 1/4 subsample resolution.  * 
 *-------------------------------------------------------------------*/ 
#include  
#include "../include/amr_plus.h" 
/* locals functions */ 
/*-------------------------------------------------------------------* 
 * Function  pred_lt4:                                               * 
 *           ~~~~~~~~~                                               * 
 *-------------------------------------------------------------------* 
 * Compute the result of long term prediction with fractionnal       * 
 * interpolation of resolution 1/4.                                  * 
 *                                                                   * 
 * On return exc[0..L_subfr-1] contains the interpolated signal      * 
 *   (adaptive codebook excitation)                                  * 
 *-------------------------------------------------------------------*/ 
void pred_lt4( 
  float exc[],       /* in/out: excitation buffer */ 
  int   T0,          /* input : integer pitch lag */ 
  int   frac,        /* input : fraction of lag   */ 
  int   L_subfr      /* input : subframe size     */ 
) 
{ 
  int   i, j; 
  float s, *x0, *x1, *x2, *c1, *c2; 
  x0 = &exc[-T0]; 
  frac = -frac; 
  if (frac < 0) { 
    frac += PIT_UP_SAMP; 
    x0--; 
  } 
  for (j=0; j