www.pudn.com > source.rar > GAINPRED.C

/* ITU-T G.729 Software Package Release 2 (November 2006) */ 
/* 
   ITU-T G.729 Annex C - Reference C code for floating point 
                         implementation of G.729 
                         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 : GAINPRED.C 
 Used for the floating point version of both 
 G.729 main body and G.729A 
*/ 
 
#include  
#include "typedef.h" 
#include "version.h" 
#ifdef VER_G729A 
 #include "ld8a.h" 
 #include "tab_ld8a.h" 
#else 
 #include "ld8k.h" 
 #include "tab_ld8k.h" 
#endif 
 
/*---------------------------------------------------------------------------* 
 * Function  Gain_predict                                                    * 
 * ~~~~~~~~~~~~~~~~~~~~~~                                                    * 
 * MA prediction is performed on the innovation energy (in dB with mean      * 
 * removed).                                                                 * 
 *---------------------------------------------------------------------------*/ 
void gain_predict( 
   FLOAT past_qua_en[], /* (i)     :Past quantized energies        */ 
   FLOAT code[],        /* (i)     :Innovative vector.             */ 
   int l_subfr,         /* (i)     :Subframe length.               */ 
   FLOAT *gcode0        /* (o)     :Predicted codebook gain        */ 
) 
{ 
   FLOAT ener_code, pred_code; 
   int i; 
 
   pred_code = MEAN_ENER ; 
 
   /* innovation energy */ 
   ener_code = (F)0.01; 
   for(i=0; i 0; i--) 
     past_qua_en[i] = past_qua_en[i-1]; 
   past_qua_en[0] = (F)20.0*(FLOAT)log10((double)g_code); 
 
   return; 
} 
 
/*---------------------------------------------------------------------------* 
 * Function  gain_update_erasure                                             * 
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                             * 
 * update table of past quantized energies (frame erasure)                   * 
 *---------------------------------------------------------------------------* 
 *     av_pred_en = 0.0;                                                     * 
 *     for (i = 0; i < 4; i++)                                               * 
 *        av_pred_en += past_qua_en[i];                                      * 
 *     av_pred_en = av_pred_en*0.25 - 4.0;                                   * 
 *     if (av_pred_en < -14.0) av_pred_en = -14.0;                           * 
 *---------------------------------------------------------------------------*/ 
void gain_update_erasure( 
   FLOAT past_qua_en[]     /* input/output:Past quantized energies        */ 
) 
{ 
   int i; 
   FLOAT  av_pred_en; 
 
    av_pred_en = (F)0.0; 
    for (i = 0; i < 4; i++) 
        av_pred_en += past_qua_en[i]; 
    av_pred_en = av_pred_en*(F)0.25 - (F)4.0; 
    if (av_pred_en < (F)-14.0) av_pred_en = (F)-14.0; 
 
    for (i = 3; i > 0; i--) 
        past_qua_en[i] = past_qua_en[i-1]; 
    past_qua_en[0] = av_pred_en; 
 
    return; 
}