summaryrefslogtreecommitdiff
path: root/libavcodec/h264idct.c
blob: 649fcc48058cf8eeb54f6b7acf7550db50b05a51 (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
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/*
 * H.264 IDCT
 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/**
 * @file h264-idct.c
 * H.264 IDCT.
 * @author Michael Niedermayer <michaelni@gmx.at>
 */

#include "dsputil.h"

static always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){
    int i;
    uint8_t *cm = cropTbl + MAX_NEG_CROP;

    block[0] += 1<<(shift-1);

    for(i=0; i<4; i++){
        const int z0=  block[0 + block_stride*i]     +  block[2 + block_stride*i];
        const int z1=  block[0 + block_stride*i]     -  block[2 + block_stride*i];
        const int z2= (block[1 + block_stride*i]>>1) -  block[3 + block_stride*i];
        const int z3=  block[1 + block_stride*i]     + (block[3 + block_stride*i]>>1);

        block[0 + block_stride*i]= z0 + z3;
        block[1 + block_stride*i]= z1 + z2;
        block[2 + block_stride*i]= z1 - z2;
        block[3 + block_stride*i]= z0 - z3;
    }

    for(i=0; i<4; i++){
        const int z0=  block[i + block_stride*0]     +  block[i + block_stride*2];
        const int z1=  block[i + block_stride*0]     -  block[i + block_stride*2];
        const int z2= (block[i + block_stride*1]>>1) -  block[i + block_stride*3];
        const int z3=  block[i + block_stride*1]     + (block[i + block_stride*3]>>1);

        dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ];
        dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ];
        dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ];
        dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ];
    }
}

void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){
    idct_internal(dst, block, stride, 4, 6, 1);
}

void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
    idct_internal(dst, block, stride, 8, 3, 1);
}

void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){
    idct_internal(dst, block, stride, 8, 3, 0);
}

void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){
    int i;
    DCTELEM (*src)[8] = (DCTELEM(*)[8])block;
    uint8_t *cm = cropTbl + MAX_NEG_CROP;

    block[0] += 32;

    for( i = 0; i < 8; i++ )
    {
        const int a0 =  src[i][0] + src[i][4];
        const int a2 =  src[i][0] - src[i][4];
        const int a4 = (src[i][2]>>1) - src[i][6];
        const int a6 = (src[i][6]>>1) + src[i][2];

        const int b0 = a0 + a6;
        const int b2 = a2 + a4;
        const int b4 = a2 - a4;
        const int b6 = a0 - a6;

        const int a1 = -src[i][3] + src[i][5] - src[i][7] - (src[i][7]>>1);
        const int a3 =  src[i][1] + src[i][7] - src[i][3] - (src[i][3]>>1);
        const int a5 = -src[i][1] + src[i][7] + src[i][5] + (src[i][5]>>1);
        const int a7 =  src[i][3] + src[i][5] + src[i][1] + (src[i][1]>>1);

        const int b1 = (a7>>2) + a1;
        const int b3 =  a3 + (a5>>2);
        const int b5 = (a3>>2) - a5;
        const int b7 =  a7 - (a1>>2);

        src[i][0] = b0 + b7;
        src[i][7] = b0 - b7;
        src[i][1] = b2 + b5;
        src[i][6] = b2 - b5;
        src[i][2] = b4 + b3;
        src[i][5] = b4 - b3;
        src[i][3] = b6 + b1;
        src[i][4] = b6 - b1;
    }
    for( i = 0; i < 8; i++ )
    {
        const int a0 =  src[0][i] + src[4][i];
        const int a2 =  src[0][i] - src[4][i];
        const int a4 = (src[2][i]>>1) - src[6][i];
        const int a6 = (src[6][i]>>1) + src[2][i];

        const int b0 = a0 + a6;
        const int b2 = a2 + a4;
        const int b4 = a2 - a4;
        const int b6 = a0 - a6;

        const int a1 = -src[3][i] + src[5][i] - src[7][i] - (src[7][i]>>1);
        const int a3 =  src[1][i] + src[7][i] - src[3][i] - (src[3][i]>>1);
        const int a5 = -src[1][i] + src[7][i] + src[5][i] + (src[5][i]>>1);
        const int a7 =  src[3][i] + src[5][i] + src[1][i] + (src[1][i]>>1);

        const int b1 = (a7>>2) + a1;
        const int b3 =  a3 + (a5>>2);
        const int b5 = (a3>>2) - a5;
        const int b7 =  a7 - (a1>>2);

        dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ];
        dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ];
        dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ];
        dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ];
        dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ];
        dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ];
        dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ];
        dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ];
    }
}