www.pudn.com > CryptoPhone-src-031122.zip > acb_code.c

/* Copyright 2001,2002,2003 NAH6 
 * All Rights Reserved 
 * 
 * Parts Copyright DoD, Parts Copyright Starium 
 * 
 */ 
          /*LINTLIBRARY*/ 
          /*PROTOLIB1*/ 
/*#include */ 
#include "main.h" 
#include "acb_code.h" 
 
/* Note: The following table was converted to 1.14 fixed-point format */ 
/* (multiply by 2^14) */ 
static fxpt_16 ACBGainTable[32] = 
{ 
-16269, -13615, -11354,  -9093,  -6783,  -3752,      0,   2277, 
  4178,   6029,   7487,   8700,   9847,  10699,  11502,  12206, 
 12780,  13369,  13926,  14434,  14991,  15532,  16105,  16712, 
 17400,  18301,  19546,  21119,  22839,  25231,  28918,  32621 
}; 
 
/************************************************************************** 
* 
* ROUTINE 
*               ACBGainEncode 
* 
* FUNCTION 
* 
*               encode and quantize ACB gain for various 
*               quantizer types. 
* 
* SYNOPSIS 
*               ACBGainEncode(UGain, *QGain) 
* 
*   formal 
* 
*                       data    I/O 
*       name            type    type    function 
*       ------------------------------------------------------------------- 
*       UGain           fxpt_16 i       pitch gain input (true value) 
*       QGain           int     o       encoded pitch gain index 
* 
*       ACBGainEncode   fxpt_16 fun     encoded pitch gain 
* 
*************************************************************************** 
* 
* DESCRIPTION 
* 
*       This funtion uses output level data obtained by Max's minimum 
*       distortion quantization priciples and quantizes to the nearest 
*       level (L1 norm).  (Using level data only was found superior to 
*       using both of Max's level and boundry data.) 
* 
*************************************************************************** 
* 
* CALLED BY 
* 
*       AdaptiveAnalysis Encode Decode 
* 
*************************************************************************** 
* 
* REFERENCES 
* 
*       Quantizing for Minimum Distorion 
*       J. Max 
*       IRE Trans. Inform. Theory, vol. IT-6, pp.7-12, Mar. 1960 
* 
**************************************************************************/ 
fxpt_16 ACBGainEncode(fxpt_16 UGain, int *QGain) 
{ 
        int i; 
        fxpt_32 gain; 
        fxpt_32 dist, low; 
 
FXPT_PUSHSTATE("ACBGainEncode", -1.0, -1.0); 
        gain = fxpt_deposit_l(UGain); 
        low = dist = fxpt_abs32(fxpt_sub32(gain, 
            fxpt_deposit_l(ACBGainTable[0]))); 
        *QGain = 0; 
        for (i=1; i<32; i++) { 
                dist = fxpt_abs32(fxpt_sub32(gain, 
                    fxpt_deposit_l(ACBGainTable[i]))); 
                if (dist < low) { 
                        low = dist; 
                        *QGain = i; 
                } 
        } 
 
FXPT_POPSTATE(); 
        return (ACBGainTable[*QGain]); 
} 
 
/************************************************************************** 
* 
* ROUTINE 
*               ACBGainDecode 
* 
* FUNCTION 
* 
*               decode ACB gain from table 
* 
* SYNOPSIS 
*               ACBGainDecode(QGain, UGain) 
* 
*   formal 
* 
*                       data    I/O 
*       name            type    type    function 
*       ------------------------------------------------------------------- 
*       QGain           int     i       Quantized ACB Gain 
*       UGain           fxpt_16 o       Unquantized ACB Gain 
* 
*************************************************************************** 
* 
*       The data used in the table generation is from 3m3f.spd. 
* 
*************************************************************************** 
* 
* REFERENCES 
* 
*       Quantizing for Minimum Distorion 
*       J. Max 
*       IRE Trans. Inform. Theory, vol. IT-6, pp.7-12, Mar. 1960 
* 
**************************************************************************/ 
void ACBGainDecode(int QGain, fxpt_16 *UGain) 
{ 
        *UGain = ACBGainTable[QGain]; 
}