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view libtwamr/pitch_fr.h @ 604:54f0f1b74c25

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libgsmhr1 TFO: require BFI=0 and SID=0 for homing In order for a received frame to be recognized as DHF, we need not only the correct bit pattern, but also BFI=0 and SID=0. The BFI=0 requirement should be obvious, while the SID=0 requirement is needed only for HR codec. With FR and EFR, SID classification comes from the payload bits and no separate check is needed - but in HR we get an out-of-band SID ternary flag. When SID=1, no payload bits are used at all; when SID=2, we use only the first 33 bits of the payload. Therefore, it is proper to conditionalize DHF acceptance on SID=0. We already implemented this logic in the just finished full decoder; now bring TFO code into agreement.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 04 Dec 2025 19:40:35 +0000
parents be8edf9e6bc1
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             : pitch_fr.h
*      Purpose          : Find the pitch period with 1/3 or 1/6 subsample
*                       : resolution (closed loop).
*
********************************************************************************
*/
#ifndef pitch_fr_h
#define pitch_fr_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "tw_amr.h"
#include "typedef.h"

/*
********************************************************************************
*                         DEFINITION OF DATA TYPES
********************************************************************************
*/
typedef struct {
   Word16 T0_prev_subframe;   /* integer pitch lag of previous sub-frame */
} Pitch_frState;
 
/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/
 
void Pitch_fr_reset (Pitch_frState *st);
/* reset of pre processing state (i.e. set state memory to zero)
   returns 0 on success
 */

Word16 Pitch_fr (        /* o   : pitch period (integer)                    */
    Pitch_frState *st,   /* i/o : State struct                              */
    enum Mode mode,      /* i   : codec mode                                */
    Word16 T_op[],       /* i   : open loop pitch lags                      */
    Word16 exc[],        /* i   : excitation buffer                         */
    Word16 xn[],         /* i   : target vector                             */
    Word16 h[],          /* i   : impulse response of synthesis and   
                                  weighting filters                         */
    Word16 L_subfr,      /* i   : Length of subframe                        */
    Word16 i_subfr,      /* i   : subframe offset                           */
    Word16 *pit_frac,    /* o   : pitch period (fractional)                 */
    Word16 *resu3,       /* o   : subsample resolution 1/3 (=1) or 1/6 (=0) */
    Word16 *ana_index    /* o   : index of encoding                         */
);
 
#endif