lpc.h

OGG文件格式音频数解压缩SDK.现在OGG文件格式在一些游戏开发中使用的比较多.

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

  function: LPC low level routines
  last mod: $Id: lpc.h,v 1.19 2002/07/11 06:40:49 xiphmont Exp $

 ********************************************************************/

#ifndef _V_LPC_H_
#define _V_LPC_H_

#include "vorbis/codec.h"
#include "smallft.h"

typedef struct lpclook{
  /* en/decode lookups */
  drft_lookup fft;

  int ln;
  int m;

} lpc_lookup;

extern void lpc_init(lpc_lookup *l,ogg_int32_t mapped, int m);
extern void lpc_clear(lpc_lookup *l);

/* simple linear scale LPC code */
extern float vorbis_lpc_from_data(float *data,float *lpc,int n,int m);
extern float vorbis_lpc_from_curve(float *curve,float *lpc,lpc_lookup *l);

extern void vorbis_lpc_predict(float *coeff,float *prime,int m,
			       float *data,ogg_int32_t n);

#endif