FreeCalypso > hg > gsm-codec-lib
view libtwamr/gain_q.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 | ccba5812fa44 |
| 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 : gainQuant.h * Purpose : Quantazation of gains * ******************************************************************************** */ #ifndef gain_q_h #define gain_q_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "tw_amr.h" #include "typedef.h" #include "gc_pred.h" #include "g_adapt.h" /* ******************************************************************************** * DEFINITION OF DATA TYPES ******************************************************************************** */ typedef struct { Word16 sf0_exp_gcode0; Word16 sf0_frac_gcode0; Word16 sf0_exp_target_en; Word16 sf0_frac_target_en; Word16 sf0_exp_coeff[5]; Word16 sf0_frac_coeff[5]; Word16 *gain_idx_ptr; gc_predState gc_predSt; gc_predState gc_predUnqSt; GainAdaptState adaptSt; } gainQuantState; /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ void gainQuant_reset (gainQuantState *st); /* reset of pre processing state (i.e. set state memory to zero) returns 0 on success */ int gainQuant( gainQuantState *st, /* i/o : State struct */ enum Mode mode, /* i : coder mode */ Word16 res[], /* i : LP residual, Q0 */ Word16 exc[], /* i : LTP excitation (unfiltered), Q0 */ Word16 code[], /* i : CB innovation (unfiltered), Q13 */ /* (unsharpened for MR475) */ Word16 xn[], /* i : Target vector. */ Word16 xn2[], /* i : Target vector. */ Word16 y1[], /* i : Adaptive codebook. */ Word16 Y2[], /* i : Filtered innovative vector. */ Word16 g_coeff[], /* i : Correlations <xn y1> <y1 y1> */ /* Compute in G_pitch(). */ Word16 even_subframe, /* i : even subframe indicator flag */ Word16 gp_limit, /* i : pitch gain limit */ Word16 *sf0_gain_pit, /* o : Pitch gain sf 0. MR475 */ Word16 *sf0_gain_cod, /* o : Code gain sf 0. MR475 */ Word16 *gain_pit, /* i/o : Pitch gain. */ Word16 *gain_cod, /* o : Code gain. */ /* MR475: gain_* unquantized in even */ /* subframes, quantized otherwise */ Word16 **anap /* o : Index of quantization */ ); #endif