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 contains constant definitions and extern declarations
 * for tables that were originally in qua_gain.tab and qgain475.tab,
 * included in both decoder and encoder modules.
 */

#ifndef	qua_gain_tab_h
#define	qua_gain_tab_h

#include "typedef.h"

/* table used in 'high' rates: MR67 MR74 */
#define VQ_SIZE_HIGHRATES 128

extern const Word16 table_gain_highrates[VQ_SIZE_HIGHRATES*4];

/* table used in 'low' rates: MR475, MR515, MR59 */
#define VQ_SIZE_LOWRATES 64

extern const Word16 table_gain_lowrates[VQ_SIZE_LOWRATES*4];

/* table that was originally in qgain475.tab */

#define MR475_VQ_SIZE 256

extern const Word16 table_gain_MR475[MR475_VQ_SIZE*4];

#endif	/* include guard */