libavcodec/lsp.h File Reference

#include <stdint.h>

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Functions
void	ff_acelp_reorder_lsf (int16_t *lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order)
	(I.F) means fixed-point value with F fractional and I integer bits
void	ff_acelp_lsf2lsp (int16_t *lsp, const int16_t *lsf, int lp_order)
	Convert LSF to LSP.
void	ff_acelp_lsp2lpc (int16_t *lp, const int16_t *lsp, int lp_half_order)
	LSP to LP conversion (3.2.6 of G.729).
void	ff_acelp_lp_decode (int16_t *lp_1st, int16_t *lp_2nd, const int16_t *lsp_2nd, const int16_t *lsp_prev, int lp_order)
	Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729).

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Function Documentation

void ff_acelp_lp_decode	(	int16_t *	lp_1st,
		int16_t *	lp_2nd,
		const int16_t *	lsp_2nd,
		const int16_t *	lsp_prev,
		int	lp_order
	)

Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729).

Parameters:

	lp_1st	[out] decoded LP coefficients for first subframe (-0x8000 <= (3.12) < 0x8000)
	lp_2nd	[out] decoded LP coefficients for second subframe (-0x8000 <= (3.12) < 0x8000)
	lsp_2nd	LSP coefficients of the second subframe (-0x8000 <= (0.15) < 0x8000)
	lsp_prev	LSP coefficients from the second subframe of the previous frame (-0x8000 <= (0.15) < 0x8000)
	lp_order	LP filter order

Definition at line 103 of file lsp.c.

void ff_acelp_lsf2lsp	(	int16_t *	lsp,
		const int16_t *	lsf,
		int	lp_order
	)

Convert LSF to LSP.

Parameters:

	lsp	[out] LSP coefficients (-0x8000 <= (0.15) < 0x8000)
	lsf	normalized LSF coefficients (0 <= (2.13) < 0x2000 * PI)
	lp_order	LP filter order

Remarks:

It is safe to pass the same array into the lsf and lsp parameters.

Definition at line 49 of file lsp.c.

void ff_acelp_lsp2lpc	(	int16_t *	lp,
		const int16_t *	lsp,
		int	lp_half_order
	)

LSP to LP conversion (3.2.6 of G.729).

Parameters:

	lp	[out] decoded LP coefficients (-0x8000 <= (3.12) < 0x8000)
	lsp	LSP coefficients (-0x8000 <= (0.15) < 0x8000)
	lp_half_order	LP filter order, divided by 2

Definition at line 81 of file lsp.c.

Referenced by ff_acelp_lp_decode().

void ff_acelp_reorder_lsf	(	int16_t *	lsfq,
		int	lsfq_min_distance,
		int	lsfq_min,
		int	lsfq_max,
		int	lp_order
	)

(I.F) means fixed-point value with F fractional and I integer bits

ensure a minimum distance between LSFs

Parameters:

	lsfq	[in/out] LSF to check and adjust
	lsfq_min_distance	minimum distance between LSFs
	lsfq_min	minimum allowed LSF value
	lsfq_max	maximum allowed LSF value
	lp_order	LP filter order

Definition at line 31 of file lsp.c.