FreeCalypso > hg > gsm-codec-lib
view libtwamr/preemph.h @ 605:63f774192906
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 | 3618b5cf25a6 |
| 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 : preemph.h * Purpose : Preemphasis filtering * Description : Filtering through 1 - g z^-1 * ******************************************************************************** */ #ifndef preemph_h #define preemph_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" /* ******************************************************************************** * DEFINITION OF DATA TYPES ******************************************************************************** */ typedef struct { Word16 mem_pre; /* filter state */ } preemphasisState; /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ void preemphasis_reset (preemphasisState *st); /* reset of preemphasis filter (i.e. set state memory to zero) returns 0 on success */ int preemphasis ( preemphasisState *st, /* (i/o): preemphasis filter state */ Word16 *signal, /* (i/o): input signal overwritten by the output */ Word16 g, /* (i) : preemphasis coefficient */ Word16 L /* (i) : size of filtering */ ); #endif