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view libtwamr/ex_ctrl.h @ 581:e2d5cad04cbf

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libgsmhr1 RxFE: store CN R0+LPC separately from speech In the original GSM 06.06 code the ECU for speech mode is entirely separate from the CN generator, maintaining separate state. (The main intertie between them is the speech vs CN state variable, distinguishing between speech and CN BFIs, in addition to the CN-specific function of distinguishing between initial and update SIDs.) In the present RxFE implementation I initially thought that we could use the same saved_frame buffer for both ECU and CN, overwriting just the first 4 params (R0 and LPC) when a valid SID comes in. However, I now realize it was a bad idea: the original code has a corner case (long sequence of speech-mode BFIs to put the ECU in state 6, then SID and CN-mode BFIs, then a good speech frame) that would be broken by that buffer reuse approach. We could eliminate this corner case by resetting the ECU state when passing through a CN insertion period, but doing so would needlessly increase the behavioral diffs between GSM 06.06 and our version. Solution: use a separate CN-specific buffer for CN R0+LPC parameters, and match the behavior of GSM 06.06 code in this regard.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 13 Feb 2025 10:02:45 +0000
parents 3f27ca24c620
children
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/*
********************************************************************************
*
*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
*                                R99   Version 3.3.0                
*                                REL-4 Version 4.1.0                
*
********************************************************************************
*
*      File             : ex_ctrl.h
*      Purpose          : Excitation Control module in background noise
*
********************************************************************************
*/
#ifndef ex_ctrl_h
#define ex_ctrl_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
#include "cnst.h"

/*
********************************************************************************
*                         LOCAL VARIABLES AND TABLES
********************************************************************************
*/
#define L_ENERGYHIST 60

/*
********************************************************************************
*                         DEFINITION OF DATA TYPES
********************************************************************************
*/
 
/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/
 
/*
**************************************************************************
*
*  Function    : Ex_ctrl
*  Purpose     : Charaterice synthesis speech and detect background noise
*  Returns     : background noise decision; 0 = bgn, 1 = no bgn
*
**************************************************************************
*/
Word16 Ex_ctrl (Word16 excitation[],   /*i/o: Current subframe excitation   */
                Word16 excEnergy,      /* i : Exc. Energy, sqrt(totEx*totEx)*/
                Word16 exEnergyHist[], /* i : History of subframe energies  */
                Word16 voicedHangover, /* i : # of fr. after last voiced fr.*/
                Word16 prevBFI,        /* i : Set i previous BFI            */
                Word16 carefulFlag     /* i : Restrict dymamic in scaling   */
);
 
#endif