FreeCalypso > hg > gsm-codec-lib
view libtwamr/ph_disp.h @ 581:e2d5cad04cbf
libgsmhr1 RxFE: store CN R0+LPC separately from speech
In the original GSM 06.06 code the ECU for speech mode is entirely
separate from the CN generator, maintaining separate state. (The
main intertie between them is the speech vs CN state variable,
distinguishing between speech and CN BFIs, in addition to the
CN-specific function of distinguishing between initial and update
SIDs.)
In the present RxFE implementation I initially thought that we could
use the same saved_frame buffer for both ECU and CN, overwriting
just the first 4 params (R0 and LPC) when a valid SID comes in.
However, I now realize it was a bad idea: the original code has a
corner case (long sequence of speech-mode BFIs to put the ECU in
state 6, then SID and CN-mode BFIs, then a good speech frame) that
would be broken by that buffer reuse approach. We could eliminate
this corner case by resetting the ECU state when passing through
a CN insertion period, but doing so would needlessly increase
the behavioral diffs between GSM 06.06 and our version.
Solution: use a separate CN-specific buffer for CN R0+LPC parameters,
and match the behavior of GSM 06.06 code in this regard.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 13 Feb 2025 10:02:45 +0000 |
| parents | bde9f5804670 |
| children |
line wrap: on
line source
/* ******************************************************************************** * * 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 : ph_disp.h * Purpose : Phase dispersion of excitation signal * ******************************************************************************** */ #ifndef ph_disp_h #define ph_disp_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "tw_amr.h" #include "typedef.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ #define PHDGAINMEMSIZE 5 #define PHDTHR1LTP 9830 /* 0.6 in Q14 */ #define PHDTHR2LTP 14746 /* 0.9 in Q14 */ #define ONFACTPLUS1 16384 /* 2.0 in Q13 */ #define ONLENGTH 2 /* ******************************************************************************** * DEFINITION OF DATA TYPES ******************************************************************************** */ typedef struct { Word16 gainMem[PHDGAINMEMSIZE]; Word16 prevState; Word16 prevCbGain; Word16 lockFull; Word16 onset; } ph_dispState; /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ /************************************************************************* * * Function: ph_disp_reset * Purpose: Initializes state memory * ************************************************************************** */ void ph_disp_reset (ph_dispState *state); /************************************************************************* * * Function: ph_disp_lock * Purpose: mark phase dispersion as locked in state struct * ************************************************************************** */ void ph_disp_lock (ph_dispState *state); /************************************************************************* * * Function: ph_disp_release * Purpose: mark phase dispersion as unlocked in state struct * ************************************************************************** */ void ph_disp_release (ph_dispState *state); /************************************************************************* * * Function: ph_disp * Purpose: perform phase dispersion according to the specified codec * mode and computes total excitation for synthesis part * if decoder * ************************************************************************** */ void ph_disp ( ph_dispState *state, /* i/o : State struct */ enum Mode mode, /* i : codec mode */ Word16 x[], /* i/o Q0 : in: LTP excitation signal */ /* out: total excitation signal */ Word16 cbGain, /* i Q1 : Codebook gain */ Word16 ltpGain, /* i Q14 : LTP gain */ Word16 inno[], /* i Q13 : Innovation vector (Q12 for 12.2) */ Word16 pitch_fac, /* i Q14 : pitch factor used to scale the LTP excitation (Q13 for 12.2) */ Word16 tmp_shift /* i Q0 : shift factor applied to sum of scaled LTP ex & innov. before rounding */ ); #endif