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