FreeCalypso > hg > gsm-codec-lib
view libtwamr/levinson.h @ 486:f35c8fd9ceba
CHANGES: document gsmrec-dump improvements
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Mon, 20 May 2024 02:07:30 +0000 |
parents | c713061b6edf |
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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