FreeCalypso > hg > gsm-codec-lib
view libtwamr/levinson.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 | c713061b6edf |
| 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 : levinson.h * Purpose : Levinson-Durbin algorithm in double precision. * : To compute the LP filter parameters from the * : speech autocorrelations. * ******************************************************************************** */ #ifndef levinson_h #define levinson_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "cnst.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /* ******************************************************************************** * DEFINITION OF DATA TYPES ******************************************************************************** */ typedef struct { Word16 old_A[M + 1]; /* Last A(z) for case of unstable filter */ } LevinsonState; /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ void Levinson_reset (LevinsonState *st); /* reset of pre processing state (i.e. set state memory to zero) returns 0 on success */ int Levinson ( LevinsonState *st, Word16 Rh[], /* i : Rh[m+1] Vector of autocorrelations (msb) */ Word16 Rl[], /* i : Rl[m+1] Vector of autocorrelations (lsb) */ Word16 A[], /* o : A[m] LPC coefficients (m = 10) */ Word16 rc[] /* o : rc[4] First 4 reflection coefficients */ ); #endif