summaryrefslogtreecommitdiff
path: root/libavcodec/h264idct.c
blob: 790f1883fdb1ebb99f4c8d83b55f3d0604518748 (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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
/*
 * H.264 IDCT
 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav 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 2.1 of the License, or (at your option) any later version.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

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

#include "dsputil.h"

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

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

    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);

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

    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);

        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;
    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

    block[0] += 32;

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

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

        const int a1 = -block[i+3*8] + block[i+5*8] - block[i+7*8] - (block[i+7*8]>>1);
        const int a3 =  block[i+1*8] + block[i+7*8] - block[i+3*8] - (block[i+3*8]>>1);
        const int a5 = -block[i+1*8] + block[i+7*8] + block[i+5*8] + (block[i+5*8]>>1);
        const int a7 =  block[i+3*8] + block[i+5*8] + block[i+1*8] + (block[i+1*8]>>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);

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

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

        const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
        const int a3 =  block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
        const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
        const int a7 =  block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>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) ];
    }
}

// assumes all AC coefs are 0
void ff_h264_idct_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
    int i, j;
    int dc = (block[0] + 32) >> 6;
    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP + dc;
    for( j = 0; j < 4; j++ )
    {
        for( i = 0; i < 4; i++ )
            dst[i] = cm[ dst[i] ];
        dst += stride;
    }
}

void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
    int i, j;
    int dc = (block[0] + 32) >> 6;
    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP + dc;
    for( j = 0; j < 8; j++ )
    {
        for( i = 0; i < 8; i++ )
            dst[i] = cm[ dst[i] ];
        dst += stride;
    }
}

//FIXME this table is a duplicate from h264data.h, and will be removed once the tables from, h264 have been split
static const uint8_t scan8[16 + 2*4]={
 4+1*8, 5+1*8, 4+2*8, 5+2*8,
 6+1*8, 7+1*8, 6+2*8, 7+2*8,
 4+3*8, 5+3*8, 4+4*8, 5+4*8,
 6+3*8, 7+3*8, 6+4*8, 7+4*8,
 1+1*8, 2+1*8,
 1+2*8, 2+2*8,
 1+4*8, 2+4*8,
 1+5*8, 2+5*8,
};

void ff_h264_idct_add16_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
    int i;
    for(i=0; i<16; i++){
        int nnz = nnzc[ scan8[i] ];
        if(nnz){
            if(nnz==1 && block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
            else                      idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
        }
    }
}

void ff_h264_idct_add16intra_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
    int i;
    for(i=0; i<16; i++){
        if(nnzc[ scan8[i] ]) idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
        else if(block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
    }
}

void ff_h264_idct8_add4_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
    int i;
    for(i=0; i<16; i+=4){
        int nnz = nnzc[ scan8[i] ];
        if(nnz){
            if(nnz==1 && block[i*16]) ff_h264_idct8_dc_add_c(dst + block_offset[i], block + i*16, stride);
            else                      ff_h264_idct8_add_c   (dst + block_offset[i], block + i*16, stride);
        }
    }
}

void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
    int i;
    for(i=16; i<16+8; i++){
        if(nnzc[ scan8[i] ])
            ff_h264_idct_add_c   (dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
        else if(block[i*16])
            ff_h264_idct_dc_add_c(dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
    }
}
/**
 * IDCT transforms the 16 dc values and dequantizes them.
 * @param qp quantization parameter
 */
void ff_h264_luma_dc_dequant_idct_c(DCTELEM *output, DCTELEM *input, int qmul){
#define stride 16
    int i;
    int temp[16];
    static const uint8_t x_offset[4]={0, 2*stride, 8*stride, 10*stride};

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

        temp[4*i+0]= z0+z3;
        temp[4*i+1]= z0-z3;
        temp[4*i+2]= z1-z2;
        temp[4*i+3]= z1+z2;
    }

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

        output[stride* 0+offset]= ((((z0 + z3)*qmul + 128 ) >> 8));
        output[stride* 1+offset]= ((((z1 + z2)*qmul + 128 ) >> 8));
        output[stride* 4+offset]= ((((z1 - z2)*qmul + 128 ) >> 8));
        output[stride* 5+offset]= ((((z0 - z3)*qmul + 128 ) >> 8));
    }
#undef stride
}

void ff_h264_chroma_dc_dequant_idct_c(DCTELEM *block, int qmul){
    const int stride= 16*2;
    const int xStride= 16;
    int a,b,c,d,e;

    a= block[stride*0 + xStride*0];
    b= block[stride*0 + xStride*1];
    c= block[stride*1 + xStride*0];
    d= block[stride*1 + xStride*1];

    e= a-b;
    a= a+b;
    b= c-d;
    c= c+d;

    block[stride*0 + xStride*0]= ((a+c)*qmul) >> 7;
    block[stride*0 + xStride*1]= ((e+b)*qmul) >> 7;
    block[stride*1 + xStride*0]= ((a-c)*qmul) >> 7;
    block[stride*1 + xStride*1]= ((e-b)*qmul) >> 7;
}