blob: fe4cb269411c887c13b7480c93a773b9960d8539 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
/********************************************************************
* *
* 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 1994-2001 *
* by the XIPHOPHORUS Company http://www.xiph.org/ *
********************************************************************
function: window functions
last mod: $Id: window.c,v 1.13 2001/02/26 03:50:43 xiphmont Exp $
********************************************************************/
#include <stdlib.h>
#include <math.h>
#include "os.h"
#include "misc.h"
float *_vorbis_window(int type, int window,int left,int right){
float *ret=_ogg_calloc(window,sizeof(float));
switch(type){
case 0:
/* The 'vorbis window' (window 0) is sin(sin(x)*sin(x)*2pi) */
{
int leftbegin=window/4-left/2;
int rightbegin=window-window/4-right/2;
int i;
for(i=0;i<left;i++){
float x=(i+.5f)/left*M_PI/2.;
x=sin(x);
x*=x;
x*=M_PI/2.f;
x=sin(x);
ret[i+leftbegin]=x;
}
for(i=leftbegin+left;i<rightbegin;i++)
ret[i]=1.f;
for(i=0;i<right;i++){
float x=(right-i-.5f)/right*M_PI/2.;
x=sin(x);
x*=x;
x*=M_PI/2.f;
x=sin(x);
ret[i+rightbegin]=x;
}
}
break;
default:
_ogg_free(ret);
return(NULL);
}
return(ret);
}
|
