1/*
2 * Floating point AAN IDCT
3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21#include "faanidct.h"
22
23/* To allow switching to double. */
24#define FLOAT float
25
26#define B0 1.0000000000000000000000
27#define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
28#define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
29#define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
30#define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
31#define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
32#define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
33#define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
34
35#define A4 0.70710678118654752438 // cos(pi*4/16)
36#define A2 0.92387953251128675613 // cos(pi*2/16)
37
38static const FLOAT prescale[64]={
39B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
40B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
41B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
42B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
43B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
44B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
45B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
46B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
47};
48
49static inline void p8idct(DCTELEM data[64], FLOAT temp[64], uint8_t *dest, int stride, int x, int y, int type){
50    int i;
51    FLOAT av_unused tmp0;
52    FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
53    FLOAT os07, os16, os25, os34;
54    FLOAT od07, od16, od25, od34;
55
56    for(i=0; i<y*8; i+=y){
57        s17= temp[1*x + i] + temp[7*x + i];
58        d17= temp[1*x + i] - temp[7*x + i];
59        s53= temp[5*x + i] + temp[3*x + i];
60        d53= temp[5*x + i] - temp[3*x + i];
61
62        od07=  s17 + s53;
63        od25= (s17 - s53)*(2*A4);
64
65#if 0 //these 2 are equivalent
66        tmp0= (d17 + d53)*(2*A2);
67        od34=  d17*( 2*B6) - tmp0;
68        od16=  d53*(-2*B2) + tmp0;
69#else
70        od34=  d17*(2*(B6-A2)) - d53*(2*A2);
71        od16=  d53*(2*(A2-B2)) + d17*(2*A2);
72#endif
73
74        od16 -= od07;
75        od25 -= od16;
76        od34 += od25;
77
78        s26 = temp[2*x + i] + temp[6*x + i];
79        d26 = temp[2*x + i] - temp[6*x + i];
80        d26*= 2*A4;
81        d26-= s26;
82
83        s04= temp[0*x + i] + temp[4*x + i];
84        d04= temp[0*x + i] - temp[4*x + i];
85
86        os07= s04 + s26;
87        os34= s04 - s26;
88        os16= d04 + d26;
89        os25= d04 - d26;
90
91        if(type==0){
92            temp[0*x + i]= os07 + od07;
93            temp[7*x + i]= os07 - od07;
94            temp[1*x + i]= os16 + od16;
95            temp[6*x + i]= os16 - od16;
96            temp[2*x + i]= os25 + od25;
97            temp[5*x + i]= os25 - od25;
98            temp[3*x + i]= os34 - od34;
99            temp[4*x + i]= os34 + od34;
100        }else if(type==1){
101            data[0*x + i]= lrintf(os07 + od07);
102            data[7*x + i]= lrintf(os07 - od07);
103            data[1*x + i]= lrintf(os16 + od16);
104            data[6*x + i]= lrintf(os16 - od16);
105            data[2*x + i]= lrintf(os25 + od25);
106            data[5*x + i]= lrintf(os25 - od25);
107            data[3*x + i]= lrintf(os34 - od34);
108            data[4*x + i]= lrintf(os34 + od34);
109        }else if(type==2){
110            dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
111            dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
112            dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
113            dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
114            dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
115            dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
116            dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
117            dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
118        }else{
119            dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
120            dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
121            dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
122            dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
123            dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
124            dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
125            dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
126            dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
127        }
128    }
129}
130
131void ff_faanidct(DCTELEM block[64]){
132    FLOAT temp[64];
133    int i;
134
135    emms_c();
136
137    for(i=0; i<64; i++)
138        temp[i] = block[i] * prescale[i];
139
140    p8idct(block, temp, NULL, 0, 1, 8, 0);
141    p8idct(block, temp, NULL, 0, 8, 1, 1);
142}
143
144void ff_faanidct_add(uint8_t *dest, int line_size, DCTELEM block[64]){
145    FLOAT temp[64];
146    int i;
147
148    emms_c();
149
150    for(i=0; i<64; i++)
151        temp[i] = block[i] * prescale[i];
152
153    p8idct(block, temp, NULL,         0, 1, 8, 0);
154    p8idct(NULL , temp, dest, line_size, 8, 1, 2);
155}
156
157void ff_faanidct_put(uint8_t *dest, int line_size, DCTELEM block[64]){
158    FLOAT temp[64];
159    int i;
160
161    emms_c();
162
163    for(i=0; i<64; i++)
164        temp[i] = block[i] * prescale[i];
165
166    p8idct(block, temp, NULL,         0, 1, 8, 0);
167    p8idct(NULL , temp, dest, line_size, 8, 1, 3);
168}
169