libavcodec/lpc.h File Reference

#include <stdint.h>
#include "dsputil.h"

Go to the source code of this file.

Defines

#define ORDER_METHOD_EST   0
 LPC utility code Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>.
#define ORDER_METHOD_2LEVEL   1
#define ORDER_METHOD_4LEVEL   2
#define ORDER_METHOD_8LEVEL   3
#define ORDER_METHOD_SEARCH   4
#define ORDER_METHOD_LOG   5
#define MIN_LPC_ORDER   1
#define MAX_LPC_ORDER   32
#define LPC_TYPE   float

Functions

int ff_lpc_calc_coefs (DSPContext *s, const int32_t *samples, int blocksize, int min_order, int max_order, int precision, int32_t coefs[][MAX_LPC_ORDER], int *shift, int use_lpc, int omethod, int max_shift, int zero_shift)
 Calculate LPC coefficients for multiple orders.
void ff_lpc_compute_autocorr (const int32_t *data, int len, int lag, double *autoc)
 Calculates autocorrelation data from audio samples A Welch window function is applied before calculation.
static int compute_lpc_coefs (const LPC_TYPE *autoc, int max_order, LPC_TYPE *lpc, int lpc_stride, int fail, int normalize)
 Levinson-Durbin recursion.


Define Documentation

#define LPC_TYPE   float

Definition at line 54 of file lpc.h.

Referenced by compute_lpc_coefs().

#define MAX_LPC_ORDER   32

Definition at line 36 of file lpc.h.

Referenced by calc_predictor_params(), encode_residual(), and flac_encode_init().

#define MIN_LPC_ORDER   1

Definition at line 35 of file lpc.h.

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

#define ORDER_METHOD_2LEVEL   1

Definition at line 29 of file lpc.h.

Referenced by encode_residual(), and flac_encode_init().

#define ORDER_METHOD_4LEVEL   2

Definition at line 30 of file lpc.h.

Referenced by encode_residual(), and flac_encode_init().

#define ORDER_METHOD_8LEVEL   3

Definition at line 31 of file lpc.h.

Referenced by encode_residual(), and flac_encode_init().

#define ORDER_METHOD_EST   0

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 28 of file lpc.h.

Referenced by calc_predictor_params(), ff_lpc_calc_coefs(), and flac_encode_init().

#define ORDER_METHOD_LOG   5

Definition at line 33 of file lpc.h.

Referenced by encode_residual(), and flac_encode_init().

#define ORDER_METHOD_SEARCH   4

Definition at line 32 of file lpc.h.

Referenced by encode_residual(), and flac_encode_init().


Function Documentation

static int compute_lpc_coefs ( const LPC_TYPE *  autoc,
int  max_order,
LPC_TYPE *  lpc,
int  lpc_stride,
int  fail,
int  normalize 
) [inline, static]

Levinson-Durbin recursion.

Produces LPC coefficients from autocorrelation data.

Definition at line 61 of file lpc.h.

Referenced by apply_tns(), backward_filter(), and ff_lpc_calc_coefs().

int ff_lpc_calc_coefs ( DSPContext s,
const int32_t *  samples,
int  blocksize,
int  min_order,
int  max_order,
int  precision,
int32_t  coefs[][MAX_LPC_ORDER],
int *  shift,
int  use_lpc,
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 165 of file lpc.c.

Referenced by calc_predictor_params(), and encode_residual().

void ff_lpc_compute_autocorr ( const int32_t *  data,
int  len,
int  lag,
double *  autoc 
)

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

Definition at line 58 of file lpc.c.

Referenced by dsputil_init().


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