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view libtwamr/enc_lag3.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 0349de7c45b7
children
line wrap: on
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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             : enc_lag3.h
*      Purpose          : Encoding of fractional pitch lag with 1/3 resolution.
*
********************************************************************************
*/
#ifndef enc_lag3_h
#define enc_lag3_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
 
/*
********************************************************************************
*                         DEFINITION OF DATA TYPES
********************************************************************************
*/
 
/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/
Word16
Enc_lag3(                /* o  : Return index of encoding     */
    Word16 T0,           /* i  : Pitch delay                          */
    Word16 T0_frac,      /* i  : Fractional pitch delay               */
    Word16 T0_prev,      /* i  : Integer pitch delay of last subframe */
    Word16 T0_min,       /* i  : minimum of search range              */
    Word16 T0_max,       /* i  : maximum of search range              */
    Word16 delta_flag,   /* i  : Flag for 1st (or 3rd) subframe       */
    Word16 flag4         /* i  : Flag for encoding with 4 bits        */
);
 
#endif