envelope.h
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/********************************************************************
* *
* 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 1994-2009 *
* by the Xiph.Org Foundation http://www.xiph.org/ *
* *
********************************************************************
function: PCM data envelope analysis and manipulation
********************************************************************/
#ifndef _V_ENVELOPE_
#define _V_ENVELOPE_
#include "mdct.h"
#define VE_PRE 16
#define VE_WIN 4
#define VE_POST 2
#define VE_AMP (VE_PRE+VE_POST-1)
#define VE_BANDS 7
#define VE_NEARDC 15
#define VE_MINSTRETCH 2 /* a bit less than short block */
#define VE_MAXSTRETCH 12 /* one-third full block */
typedef struct {
float ampbuf[VE_AMP];
int ampptr;
float nearDC[VE_NEARDC];
float nearDC_acc;
float nearDC_partialacc;
int nearptr;
} envelope_filter_state;
typedef struct {
int begin;
int end;
float *window;
float total;
} envelope_band;
typedef struct {
int ch;
int winlength;
int searchstep;
float minenergy;
mdct_lookup mdct;
float *mdct_win;
envelope_band band[VE_BANDS];
envelope_filter_state *filter;
int stretch;
int *mark;
long storage;
long current;
long curmark;
long cursor;
} 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);
extern void _ve_envelope_shift(envelope_lookup *e,long shift);
extern int _ve_envelope_mark(vorbis_dsp_state *v);
#endif