blob: ed2dc251824131a9882f13224b5487ae646a2fb9 (
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
|
/********************************************************************
* *
* THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
* THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. *
* PLEASE READ THESE TERMS DISTRIBUTING. *
* *
* THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000 *
* by Monty <monty@xiph.org> and The XIPHOPHORUS Company *
* http://www.xiph.org/ *
* *
********************************************************************
function: window functions
last mod: $Id: window.c,v 1.3 1999/12/30 07:26:55 xiphmont Exp $
********************************************************************/
#include <stdlib.h>
#include <math.h>
#include "os.h"
/* The 'vorbis window' is sin(sin(x)*sin(x)*2pi) */
double *_vorbis_window(int window,int left,int right){
double *ret=calloc(window,sizeof(double));
int leftbegin=window/4-left/2;
int rightbegin=window-window/4-right/2;
int i;
for(i=0;i<left;i++){
double x=(i+.5)/left*M_PI/2.;
x=sin(x);
x*=x;
x*=M_PI/2.;
x=sin(x);
ret[i+leftbegin]=x;
}
for(i=leftbegin+left;i<rightbegin;i++)
ret[i]=1.;
for(i=0;i<right;i++){
double x=(right-i-.5)/right*M_PI/2.;
x=sin(x);
x*=x;
x*=M_PI/2.;
x=sin(x);
ret[i+rightbegin]=x;
}
return(ret);
}
|
