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view libtwamr/autocorr.h @ 605:63f774192906

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gsmhr_decoder_twts002_in(): set BFI=1 SID=1 for invalid SID When a received TW-TS-002 RTP payload indicates invalid SID, which of the 3 possible BFI/SID combinations should we pass to our internal ETSI-based speech decoder or TFO engine? Our original code passed BFI=0 SID=1, but upon further reflection, BFI=1 SID=1 is a better choice. In the corner case where received invalid SID is fed to a full decoder in homed state, setting BFI=1 allows that decoder to emit zeros on PCM and stay homed, instead of launching into full decoding.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 04 Dec 2025 21:01:46 +0000
parents 54f6bc41ed10
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             : autocorr.h
*      Purpose          : Compute autocorrelations of signal with windowing
*
********************************************************************************
*/
#ifndef autocorr_h
#define autocorr_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
 
/*
********************************************************************************
*                         DEFINITION OF DATA TYPES
********************************************************************************
*/
 
/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/
/*
**************************************************************************
*
*  Function    : autocorr
*  Purpose     : Compute autocorrelations of signal with windowing
*  Description : - Windowing of input speech:   s'[n] = s[n] * w[n]
*                - Autocorrelations of input speech:
*                  r[k] = sum_{i=k}^{239} s'[i]*s'[i-k]    k=0,...,10
*                The autocorrelations are expressed in normalized 
*                double precision format.
*  Returns     : Autocorrelation
*
**************************************************************************
*/
Word16 Autocorr (
    Word16 x[],        /* (i)    : Input signal (L_WINDOW)             */
    Word16 m,          /* (i)    : LPC order                           */
    Word16 r_h[],      /* (o)    : Autocorrelations  (msb)  (MP1)      */
    Word16 r_l[],      /* (o)    : Autocorrelations  (lsb)  (MP1)      */
    const Word16 wind[]/* (i)    : window for LPC analysis. (L_WINDOW) */
);
 
#endif