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.

/*
 * This header file is internal to libtwamr (not public API);
 * it contains internal definitions for aspects of the AMR codec
 * that don't need to be in the external API.
 */

#ifndef	int_defs_h
#define	int_defs_h

/* number of speech bits for all modes */
#define	AMR_NBITS_475		95
#define	AMR_NBITS_515		103
#define	AMR_NBITS_59		118
#define	AMR_NBITS_67		134
#define	AMR_NBITS_74		148
#define	AMR_NBITS_795		159
#define	AMR_NBITS_102		204
#define	AMR_NBITS_122		244
#define	AMR_NBITS_SID		35

/* number of distinct parameters for all modes */
#define	PRMNO_MR475		17
#define	PRMNO_MR515		19
#define	PRMNO_MR59		19
#define	PRMNO_MR67		19
#define	PRMNO_MR74		19
#define	PRMNO_MR795		23
#define	PRMNO_MR102		39
#define	PRMNO_MR122		57
#define	PRMNO_MRDTX		5

/* number of parameters up to first subframe (for DHF detection) */
#define	PRMNOFSF_MR475		7
#define	PRMNOFSF_MR515		7
#define	PRMNOFSF_MR59		7
#define	PRMNOFSF_MR67		7
#define	PRMNOFSF_MR74		7
#define	PRMNOFSF_MR795		8
#define	PRMNOFSF_MR102		12
#define	PRMNOFSF_MR122		18

#endif	/* include guard */