libavcodec/lpc.c File Reference

#include "libavutil/lls.h"
#include "lpc.h"

Go to the source code of this file.

Defines
#define	LPC_USE_DOUBLE
	LPC utility code Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>.
Functions
static void	lpc_apply_welch_window_c (const int32_t *data, int len, double *w_data)
	Apply Welch window function to audio block.
static void	lpc_compute_autocorr_c (const double *data, int len, int lag, double *autoc)
	Calculate autocorrelation data from audio samples A Welch window function is applied before calculation.
static void	quantize_lpc_coefs (double *lpc_in, int order, int precision, int32_t *lpc_out, int *shift, int max_shift, int zero_shift)
	Quantize LPC coefficients.
static int	estimate_best_order (double *ref, int min_order, int max_order)
int	ff_lpc_calc_coefs (LPCContext *s, const int32_t *samples, int blocksize, int min_order, int max_order, int precision, int32_t coefs[][MAX_LPC_ORDER], int *shift, enum FFLPCType lpc_type, int lpc_passes, int omethod, int max_shift, int zero_shift)
	Calculate LPC coefficients for multiple orders.
av_cold int	ff_lpc_init (LPCContext *s, int blocksize, int max_order, enum FFLPCType lpc_type)
	Initialize LPCContext.
av_cold void	ff_lpc_end (LPCContext *s)
	Uninitialize LPCContext.

---

Define Documentation

#define LPC_USE_DOUBLE

LPC utility code Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>.

This file is part of FFmpeg.

FFmpeg is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

FFmpeg is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with FFmpeg; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Definition at line 24 of file lpc.c.

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Function Documentation

static int estimate_best_order	(	double *	ref,
		int	min_order,
		int	max_order
	)			[static]

Definition at line 135 of file lpc.c.

Referenced by ff_lpc_calc_coefs().

int ff_lpc_calc_coefs	(	LPCContext *	s,
		const int32_t *	samples,
		int	blocksize,
		int	min_order,
		int	max_order,
		int	precision,
		int32_t	coefs[][MAX_LPC_ORDER],
		int *	shift,
		enum FFLPCType	lpc_type,
		int	lpc_passes,
		int	omethod,
		int	max_shift,
		int	zero_shift
	)

Calculate LPC coefficients for multiple orders.

Parameters:

use_lpc

LPC method for determining coefficients 0 = LPC with fixed pre-defined coeffs 1 = LPC with coeffs determined by Levinson-Durbin recursion 2+ = LPC with coeffs determined by Cholesky factorization using (use_lpc-1) passes.

Definition at line 157 of file lpc.c.

Referenced by calc_predictor_params(), encode_residual_ch(), and ra144_encode_frame().

av_cold void ff_lpc_end

(

LPCContext *

s

)

Uninitialize LPCContext.

Definition at line 268 of file lpc.c.

Referenced by alac_encode_close(), ff_lpc_calc_coefs(), flac_encode_close(), and ra144_encode_close().

av_cold int ff_lpc_init	(	LPCContext *	s,
		int	blocksize,
		int	max_order,
		enum FFLPCType	lpc_type
	)

Initialize LPCContext.

Definition at line 243 of file lpc.c.

Referenced by alac_encode_init(), ff_lpc_calc_coefs(), flac_encode_init(), and ra144_encode_init().

static void lpc_apply_welch_window_c	(	const int32_t *	data,
		int	len,
		double *	w_data
	)			[static]

Apply Welch window function to audio block.

Definition at line 31 of file lpc.c.

Referenced by ff_lpc_init().

static void lpc_compute_autocorr_c	(	const double *	data,
		int	len,
		int	lag,
		double *	autoc
	)			[static]

Calculate autocorrelation data from audio samples A Welch window function is applied before calculation.

Definition at line 58 of file lpc.c.

Referenced by ff_lpc_init().

static void quantize_lpc_coefs	(	double *	lpc_in,
		int	order,
		int	precision,
		int32_t *	lpc_out,
		int *	shift,
		int	max_shift,
		int	zero_shift
	)			[static]

Quantize LPC coefficients.

Definition at line 86 of file lpc.c.

Referenced by ff_lpc_calc_coefs().