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view libtwamr/inter_36.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 838ed426bb76
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             : inter_36.h
*      Purpose          : Interpolating the normalized correlation
*                       : with 1/3 or 1/6 resolution.
*
********************************************************************************
*/
#ifndef inter_36_h
#define inter_36_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
 
/*
********************************************************************************
*                         DEFINITION OF DATA TYPES
********************************************************************************
*/
 
/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/
Word16 Interpol_3or6 (  /* (o)  : interpolated value                        */
    Word16 *x,          /* (i)  : input vector                              */
    Word16 frac,        /* (i)  : fraction  (-2..2 for 3*, -3..3 for 6*)    */
    Word16 flag3        /* (i)  : if set, upsampling rate = 3 (6 otherwise) */
);
 
#endif