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      1 /********************************************************************
      2  *                                                                  *
      3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
      4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
      5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
      6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
      7  *                                                                  *
      8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
      9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
     10  *                                                                  *
     11  ********************************************************************
     12 
     13  function: PCM data envelope analysis and manipulation
     14  last mod: $Id: envelope.h 16227 2009-07-08 06:58:46Z xiphmont $
     15 
     16  ********************************************************************/
     17 
     18 #ifndef _V_ENVELOPE_
     19 #define _V_ENVELOPE_
     20 
     21 #include "mdct.h"
     22 
     23 #define VE_PRE    16
     24 #define VE_WIN    4
     25 #define VE_POST   2
     26 #define VE_AMP    (VE_PRE+VE_POST-1)
     27 
     28 #define VE_BANDS  7
     29 #define VE_NEARDC 15
     30 
     31 #define VE_MINSTRETCH 2   /* a bit less than short block */
     32 #define VE_MAXSTRETCH 12  /* one-third full block */
     33 
     34 typedef struct {
     35   float ampbuf[VE_AMP];
     36   int   ampptr;
     37 
     38   float nearDC[VE_NEARDC];
     39   float nearDC_acc;
     40   float nearDC_partialacc;
     41   int   nearptr;
     42 
     43 } envelope_filter_state;
     44 
     45 typedef struct {
     46   int begin;
     47   int end;
     48   float *window;
     49   float total;
     50 } envelope_band;
     51 
     52 typedef struct {
     53   int ch;
     54   int winlength;
     55   int searchstep;
     56   float minenergy;
     57 
     58   mdct_lookup  mdct;
     59   float       *mdct_win;
     60 
     61   envelope_band          band[VE_BANDS];
     62   envelope_filter_state *filter;
     63   int   stretch;
     64 
     65   int                   *mark;
     66 
     67   long storage;
     68   long current;
     69   long curmark;
     70   long cursor;
     71 } envelope_lookup;
     72 
     73 extern void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi);
     74 extern void _ve_envelope_clear(envelope_lookup *e);
     75 extern long _ve_envelope_search(vorbis_dsp_state *v);
     76 extern void _ve_envelope_shift(envelope_lookup *e,long shift);
     77 extern int  _ve_envelope_mark(vorbis_dsp_state *v);
     78 
     79 
     80 #endif
     81