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.

/*
 * The original ETSI EFR code features an include file named q_plsf_5.tab,
 * included into d_homing.c, d_plsf_5.c and q_plsf_5.c, duplicating
 * the small mean_lsf[] table across all 3 modules and the other (big)
 * tables across d_plsf_5.c for the decoder and q_plsf_5.c for the encoder.
 *
 * In our version we have moved the tables into q_plsf5_tab.c,
 * with extern declarations in q_plsf5_tab.h.
 */

extern const Word16 mean_lsf[10];

#define DICO1_SIZE  128
#define DICO2_SIZE  256
#define DICO3_SIZE  256
#define DICO4_SIZE  256
#define DICO5_SIZE  64

extern const Word16 dico1_lsf[DICO1_SIZE * 4];
extern const Word16 dico2_lsf[DICO2_SIZE * 4];
extern const Word16 dico3_lsf[DICO3_SIZE * 4];
extern const Word16 dico4_lsf[DICO4_SIZE * 4];
extern const Word16 dico5_lsf[DICO5_SIZE * 4];