vorbis/lib/envelope.h

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
 * THE GNU LESSER/LIBRARY PUBLIC LICENSE, WHICH IS INCLUDED WITH    *
 * THIS SOURCE. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.        *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2000             *
 * by Monty <monty@xiph.org> and the XIPHOPHORUS Company            *
 * http://www.xiph.org/                                             *
 *                                                                  *
 ********************************************************************

 function: PCM data envelope analysis and manipulation
 last mod: $Id: envelope.h,v 1.10.2.1 2000/11/04 06:21:44 xiphmont Exp $

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

#ifndef _V_ENVELOPE_
#define _V_ENVELOPE_

#include "iir.h"
#include "smallft.h"

#define EORDER 16

typedef struct {
  int ch;
  int winlength;
  int searchstep;
  float minenergy;

  IIR_state *iir;
  float    **filtered;
  long storage;
  long current;

  drft_lookup drft;
  float *window;
} envelope_lookup;

extern void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi);
extern void _ve_envelope_clear(envelope_lookup *e);
extern long _ve_envelope_search(vorbis_dsp_state *v,long searchpoint);
extern void _ve_envelope_shift(envelope_lookup *e,long shift);


#endif