AMR pitch LPC coefficient decoding functions

Functions
static void	lsf2lsp (const float *lsf, double *lsp)
	Convert an lsf vector into an lsp vector.
static void	interpolate_lsf (float lsf_q[4][LP_FILTER_ORDER], float *lsf_new)
	Interpolate the LSF vector (used for fixed gain smoothing).
static void	lsf2lsp_for_mode12k2 (AMRContext *p, double lsp[LP_FILTER_ORDER], const float lsf_no_r[LP_FILTER_ORDER], const int16_t *lsf_quantizer[5], const int quantizer_offset, const int sign, const int update)
	Decode a set of 5 split-matrix quantized lsf indexes into an lsp vector.
static void	lsf2lsp_5 (AMRContext *p)
	Decode a set of 5 split-matrix quantized lsf indexes into 2 lsp vectors.
static void	lsf2lsp_3 (AMRContext *p)
	Decode a set of 3 split-matrix quantized lsf indexes into an lsp vector.

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Function Documentation

static void interpolate_lsf	(	float	lsf_q[4][LP_FILTER_ORDER],
		float *	lsf_new
	)		[static]

Interpolate the LSF vector (used for fixed gain smoothing).

The interpolation is done over all four subframes even in MODE_12k2.

Parameters:

[in,out]	lsf_q	LSFs in [0,1] for each subframe
[in]	lsf_new	New LSFs in [0,1] for subframe 4

Definition at line 245 of file amrnbdec.c.

Referenced by lsf2lsp_3(), and lsf2lsp_for_mode12k2().

static void lsf2lsp	(	const float *	lsf,
		double *	lsp
	)		[static]

Convert an lsf vector into an lsp vector.

Parameters:

lsf	input lsf vector
lsp	output lsp vector

Definition at line 230 of file amrnbdec.c.

Referenced by lsf2lsp_3(), and lsf2lsp_for_mode12k2().

static void lsf2lsp_3

(

AMRContext *

p

)

[static]

Decode a set of 3 split-matrix quantized lsf indexes into an lsp vector.

Parameters:

p	pointer to the AMRContext

Definition at line 333 of file amrnbdec.c.

Referenced by amrnb_decode_frame().

static void lsf2lsp_5

(

AMRContext *

p

)

[static]

Decode a set of 5 split-matrix quantized lsf indexes into 2 lsp vectors.

Parameters:

p	pointer to the AMRContext

Definition at line 304 of file amrnbdec.c.

Referenced by amrnb_decode_frame().

static void lsf2lsp_for_mode12k2	(	AMRContext *	p,
		double	lsp[LP_FILTER_ORDER],
		const float	lsf_no_r[LP_FILTER_ORDER],
		const int16_t *	lsf_quantizer[5],
		const int	quantizer_offset,
		const int	sign,
		const int	update
	)		[static]

Decode a set of 5 split-matrix quantized lsf indexes into an lsp vector.

Parameters:

p	the context
lsp	output LSP vector
lsf_no_r	LSF vector without the residual vector added
lsf_quantizer	pointers to LSF dictionary tables
quantizer_offset	offset in tables
sign	for the 3 dictionary table
update	store data for computing the next frame's LSFs

Definition at line 266 of file amrnbdec.c.

Referenced by lsf2lsp_5().