media/libvorbis/lib/vorbis_lookup.c@6474c204b198 (annotated)
media/libvorbis/lib/vorbis_lookup.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /******************************************************************** |
| michael@0 | 2 | * * |
| michael@0 | 3 | * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * |
| michael@0 | 4 | * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * |
| michael@0 | 5 | * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * |
| michael@0 | 6 | * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * |
| michael@0 | 7 | * * |
| michael@0 | 8 | * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * |
| michael@0 | 9 | * by the Xiph.Org Foundation http://www.xiph.org/ * |
| michael@0 | 10 | * * |
| michael@0 | 11 | ******************************************************************** |
| michael@0 | 12 | |
| michael@0 | 13 | function: lookup based functions |
| michael@0 | 14 | last mod: $Id: lookup.c 16227 2009-07-08 06:58:46Z xiphmont $ |
| michael@0 | 15 | |
| michael@0 | 16 | ********************************************************************/ |
| michael@0 | 17 | |
| michael@0 | 18 | #include <math.h> |
| michael@0 | 19 | #include "lookup.h" |
| michael@0 | 20 | #include "lookup_data.h" |
| michael@0 | 21 | #include "os.h" |
| michael@0 | 22 | #include "misc.h" |
| michael@0 | 23 | |
| michael@0 | 24 | #ifdef FLOAT_LOOKUP |
| michael@0 | 25 | |
| michael@0 | 26 | /* interpolated lookup based cos function, domain 0 to PI only */ |
| michael@0 | 27 | float vorbis_coslook(float a){ |
| michael@0 | 28 | double d=a*(.31830989*(float)COS_LOOKUP_SZ); |
| michael@0 | 29 | int i=vorbis_ftoi(d-.5); |
| michael@0 | 30 | |
| michael@0 | 31 | return COS_LOOKUP[i]+ (d-i)*(COS_LOOKUP[i+1]-COS_LOOKUP[i]); |
| michael@0 | 32 | } |
| michael@0 | 33 | |
| michael@0 | 34 | /* interpolated 1./sqrt(p) where .5 <= p < 1. */ |
| michael@0 | 35 | float vorbis_invsqlook(float a){ |
| michael@0 | 36 | double d=a*(2.f*(float)INVSQ_LOOKUP_SZ)-(float)INVSQ_LOOKUP_SZ; |
| michael@0 | 37 | int i=vorbis_ftoi(d-.5f); |
| michael@0 | 38 | return INVSQ_LOOKUP[i]+ (d-i)*(INVSQ_LOOKUP[i+1]-INVSQ_LOOKUP[i]); |
| michael@0 | 39 | } |
| michael@0 | 40 | |
| michael@0 | 41 | /* interpolated 1./sqrt(p) where .5 <= p < 1. */ |
| michael@0 | 42 | float vorbis_invsq2explook(int a){ |
| michael@0 | 43 | return INVSQ2EXP_LOOKUP[a-INVSQ2EXP_LOOKUP_MIN]; |
| michael@0 | 44 | } |
| michael@0 | 45 | |
| michael@0 | 46 | #include <stdio.h> |
| michael@0 | 47 | /* interpolated lookup based fromdB function, domain -140dB to 0dB only */ |
| michael@0 | 48 | float vorbis_fromdBlook(float a){ |
| michael@0 | 49 | int i=vorbis_ftoi(a*((float)(-(1<<FROMdB2_SHIFT)))-.5f); |
| michael@0 | 50 | return (i<0)?1.f: |
| michael@0 | 51 | ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f: |
| michael@0 | 52 | FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]); |
| michael@0 | 53 | } |
| michael@0 | 54 | |
| michael@0 | 55 | #endif |
| michael@0 | 56 | |
| michael@0 | 57 | #ifdef INT_LOOKUP |
| michael@0 | 58 | /* interpolated 1./sqrt(p) where .5 <= a < 1. (.100000... to .111111...) in |
| michael@0 | 59 | 16.16 format |
| michael@0 | 60 | |
| michael@0 | 61 | returns in m.8 format */ |
| michael@0 | 62 | long vorbis_invsqlook_i(long a,long e){ |
| michael@0 | 63 | long i=(a&0x7fff)>>(INVSQ_LOOKUP_I_SHIFT-1); |
| michael@0 | 64 | long d=(a&INVSQ_LOOKUP_I_MASK)<<(16-INVSQ_LOOKUP_I_SHIFT); /* 0.16 */ |
| michael@0 | 65 | long val=INVSQ_LOOKUP_I[i]- /* 1.16 */ |
| michael@0 | 66 | (((INVSQ_LOOKUP_I[i]-INVSQ_LOOKUP_I[i+1])* /* 0.16 */ |
| michael@0 | 67 | d)>>16); /* result 1.16 */ |
| michael@0 | 68 | |
| michael@0 | 69 | e+=32; |
| michael@0 | 70 | if(e&1)val=(val*5792)>>13; /* multiply val by 1/sqrt(2) */ |
| michael@0 | 71 | e=(e>>1)-8; |
| michael@0 | 72 | |
| michael@0 | 73 | return(val>>e); |
| michael@0 | 74 | } |
| michael@0 | 75 | |
| michael@0 | 76 | /* interpolated lookup based fromdB function, domain -140dB to 0dB only */ |
| michael@0 | 77 | /* a is in n.12 format */ |
| michael@0 | 78 | float vorbis_fromdBlook_i(long a){ |
| michael@0 | 79 | int i=(-a)>>(12-FROMdB2_SHIFT); |
| michael@0 | 80 | return (i<0)?1.f: |
| michael@0 | 81 | ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f: |
| michael@0 | 82 | FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]); |
| michael@0 | 83 | } |
| michael@0 | 84 | |
| michael@0 | 85 | /* interpolated lookup based cos function, domain 0 to PI only */ |
| michael@0 | 86 | /* a is in 0.16 format, where 0==0, 2^^16-1==PI, return 0.14 */ |
| michael@0 | 87 | long vorbis_coslook_i(long a){ |
| michael@0 | 88 | int i=a>>COS_LOOKUP_I_SHIFT; |
| michael@0 | 89 | int d=a&COS_LOOKUP_I_MASK; |
| michael@0 | 90 | return COS_LOOKUP_I[i]- ((d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>> |
| michael@0 | 91 | COS_LOOKUP_I_SHIFT); |
| michael@0 | 92 | } |
| michael@0 | 93 | |
| michael@0 | 94 | #endif |
