lpc.c File Reference

#include "libavutil/common.h"
#include "libavutil/lls.h"
#include "libavutil/mem_internal.h"
#include "lpc.h"
#include "lpc_functions.h"
#include "libavutil/avassert.h"

Go to the source code of this file.

Macros
#define	LPC_USE_DOUBLE

Functions
static void	compute_ref_coefs (const LPC_TYPE *autoc, int max_order, LPC_TYPE *ref, LPC_TYPE *error)
	Schur recursion. More...
static void	lpc_apply_welch_window_c (const int32_t *data, ptrdiff_t len, double *w_data)
	Apply Welch window function to audio block. More...
static void	lpc_compute_autocorr_c (const double *data, ptrdiff_t len, int lag, double *autoc)
	Calculate autocorrelation data from audio samples A Welch window function is applied before calculation. More...
static void	quantize_lpc_coefs (double *lpc_in, int order, int precision, int32_t *lpc_out, int *shift, int min_shift, int max_shift, int zero_shift)
	Quantize LPC coefficients. More...
static int	estimate_best_order (double *ref, int min_order, int max_order)
int	ff_lpc_calc_ref_coefs (LPCContext *s, const int32_t *samples, int order, double *ref)
double	ff_lpc_calc_ref_coefs_f (LPCContext *s, const float *samples, int len, int order, double *ref)
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 min_shift, int max_shift, int zero_shift)
	Calculate LPC coefficients for multiple orders. More...
av_cold int	ff_lpc_init (LPCContext *s, int blocksize, int max_order, enum FFLPCType lpc_type)
	Initialize LPCContext. More...
av_cold void	ff_lpc_end (LPCContext *s)
	Uninitialize LPCContext. More...

Macro Definition Documentation

LPC_USE_DOUBLE

#define LPC_USE_DOUBLE

Definition at line 26 of file lpc.c.

Function Documentation

compute_ref_coefs()

static void compute_ref_coefs ( const LPC_TYPE *  autoc, int  max_order, LPC_TYPE *  ref, LPC_TYPE *  error  )

inlinestatic

Schur recursion.

Produces reflection coefficients from autocorrelation data.

Definition at line 35 of file lpc.c.

Referenced by ff_lpc_calc_ref_coefs(), and ff_lpc_calc_ref_coefs_f().

lpc_apply_welch_window_c()

static void lpc_apply_welch_window_c ( const int32_t *  data, ptrdiff_t  len, double *  w_data  )

static

Apply Welch window function to audio block.

Definition at line 65 of file lpc.c.

Referenced by ff_lpc_init().

lpc_compute_autocorr_c()

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

static

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

Definition at line 105 of file lpc.c.

Referenced by ff_lpc_init().

quantize_lpc_coefs()

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

static

Quantize LPC coefficients.

Definition at line 133 of file lpc.c.

Referenced by ff_lpc_calc_coefs().

estimate_best_order()

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

static

Definition at line 183 of file lpc.c.

Referenced by ff_lpc_calc_coefs().

ff_lpc_calc_ref_coefs()

int ff_lpc_calc_ref_coefs	(	LPCContext *	s,
		const int32_t *	samples,
		int	order,
		double *	ref
	)

Definition at line 197 of file lpc.c.

Referenced by cng_encode_frame().

ff_lpc_calc_ref_coefs_f()

double ff_lpc_calc_ref_coefs_f	(	LPCContext *	s,
		const float *	samples,
		int	len,
		int	order,
		double *	ref
	)

Definition at line 209 of file lpc.c.

Referenced by ff_aac_search_for_tns().

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	min_shift,
		int	max_shift,
		int	zero_shift
	)

Calculate LPC coefficients for multiple orders.

Parameters

lpc_type

LPC method for determining coefficients, see FFLPCType for details

Definition at line 238 of file lpc.c.

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

ff_lpc_init()

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

Initialize LPCContext.

Definition at line 340 of file lpc.c.

Referenced by aac_encode_init(), alac_encode_init(), checkasm_check_lpc(), cng_encode_init(), ff_lpc_calc_coefs(), flac_encode_init(), mlp_encode_init(), and ra144_encode_init().

ff_lpc_end()

av_cold void ff_lpc_end

(

LPCContext *

s

)

Uninitialize LPCContext.

Definition at line 365 of file lpc.c.

Referenced by aac_encode_end(), alac_encode_close(), checkasm_check_lpc(), cng_encode_close(), ff_lpc_calc_coefs(), flac_encode_close(), mlp_encode_close(), and ra144_encode_close().