FreeCalypso > hg > gsm-codec-lib
view libtwamr/preemph.h @ 477:4c9222d95647
libtwamr encoder: always emit frame->mode = mode;
In the original implementation of amr_encode_frame(), the 'mode' member
of the output struct was set to 0xFF if the output frame type is TX_NO_DATA.
This design was made to mimic the mode field (16-bit word) being set to
0xFFFF (or -1) in 3GPP test sequence format - but nothing actually depends
on this struct member being set in any way, and amr_frame_to_tseq()
generates the needed 0xFFFF on its own, based on frame->type being equal
to TX_NO_DATA.
It is simpler and more efficient to always set frame->mode to the actual
encoding mode in amr_encode_frame(), and this new behavior has already
been documented in doc/AMR-library-API description in anticipation of
the present change.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 18 May 2024 22:30:42 +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