1/*
2 * H.264 IDCT
3 * Copyright (c) 2004 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
22/**
23 * @file libavcodec/h264idct.c
24 * H.264 IDCT.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include "dsputil.h"
29
30static av_always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){
31    int i;
32    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
33
34    block[0] += 1<<(shift-1);
35
36    for(i=0; i<4; i++){
37        const int z0=  block[0 + block_stride*i]     +  block[2 + block_stride*i];
38        const int z1=  block[0 + block_stride*i]     -  block[2 + block_stride*i];
39        const int z2= (block[1 + block_stride*i]>>1) -  block[3 + block_stride*i];
40        const int z3=  block[1 + block_stride*i]     + (block[3 + block_stride*i]>>1);
41
42        block[0 + block_stride*i]= z0 + z3;
43        block[1 + block_stride*i]= z1 + z2;
44        block[2 + block_stride*i]= z1 - z2;
45        block[3 + block_stride*i]= z0 - z3;
46    }
47
48    for(i=0; i<4; i++){
49        const int z0=  block[i + block_stride*0]     +  block[i + block_stride*2];
50        const int z1=  block[i + block_stride*0]     -  block[i + block_stride*2];
51        const int z2= (block[i + block_stride*1]>>1) -  block[i + block_stride*3];
52        const int z3=  block[i + block_stride*1]     + (block[i + block_stride*3]>>1);
53
54        dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ];
55        dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ];
56        dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ];
57        dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ];
58    }
59}
60
61void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){
62    idct_internal(dst, block, stride, 4, 6, 1);
63}
64
65void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
66    idct_internal(dst, block, stride, 8, 3, 1);
67}
68
69void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){
70    idct_internal(dst, block, stride, 8, 3, 0);
71}
72
73void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){
74    int i;
75    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
76
77    block[0] += 32;
78
79    for( i = 0; i < 8; i++ )
80    {
81        const int a0 =  block[0+i*8] + block[4+i*8];
82        const int a2 =  block[0+i*8] - block[4+i*8];
83        const int a4 = (block[2+i*8]>>1) - block[6+i*8];
84        const int a6 = (block[6+i*8]>>1) + block[2+i*8];
85
86        const int b0 = a0 + a6;
87        const int b2 = a2 + a4;
88        const int b4 = a2 - a4;
89        const int b6 = a0 - a6;
90
91        const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
92        const int a3 =  block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
93        const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
94        const int a7 =  block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>1);
95
96        const int b1 = (a7>>2) + a1;
97        const int b3 =  a3 + (a5>>2);
98        const int b5 = (a3>>2) - a5;
99        const int b7 =  a7 - (a1>>2);
100
101        block[0+i*8] = b0 + b7;
102        block[7+i*8] = b0 - b7;
103        block[1+i*8] = b2 + b5;
104        block[6+i*8] = b2 - b5;
105        block[2+i*8] = b4 + b3;
106        block[5+i*8] = b4 - b3;
107        block[3+i*8] = b6 + b1;
108        block[4+i*8] = b6 - b1;
109    }
110    for( i = 0; i < 8; i++ )
111    {
112        const int a0 =  block[i+0*8] + block[i+4*8];
113        const int a2 =  block[i+0*8] - block[i+4*8];
114        const int a4 = (block[i+2*8]>>1) - block[i+6*8];
115        const int a6 = (block[i+6*8]>>1) + block[i+2*8];
116
117        const int b0 = a0 + a6;
118        const int b2 = a2 + a4;
119        const int b4 = a2 - a4;
120        const int b6 = a0 - a6;
121
122        const int a1 = -block[i+3*8] + block[i+5*8] - block[i+7*8] - (block[i+7*8]>>1);
123        const int a3 =  block[i+1*8] + block[i+7*8] - block[i+3*8] - (block[i+3*8]>>1);
124        const int a5 = -block[i+1*8] + block[i+7*8] + block[i+5*8] + (block[i+5*8]>>1);
125        const int a7 =  block[i+3*8] + block[i+5*8] + block[i+1*8] + (block[i+1*8]>>1);
126
127        const int b1 = (a7>>2) + a1;
128        const int b3 =  a3 + (a5>>2);
129        const int b5 = (a3>>2) - a5;
130        const int b7 =  a7 - (a1>>2);
131
132        dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ];
133        dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ];
134        dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ];
135        dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ];
136        dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ];
137        dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ];
138        dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ];
139        dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ];
140    }
141}
142
143// assumes all AC coefs are 0
144void ff_h264_idct_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
145    int i, j;
146    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
147    int dc = (block[0] + 32) >> 6;
148    for( j = 0; j < 4; j++ )
149    {
150        for( i = 0; i < 4; i++ )
151            dst[i] = cm[ dst[i] + dc ];
152        dst += stride;
153    }
154}
155
156void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
157    int i, j;
158    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
159    int dc = (block[0] + 32) >> 6;
160    for( j = 0; j < 8; j++ )
161    {
162        for( i = 0; i < 8; i++ )
163            dst[i] = cm[ dst[i] + dc ];
164        dst += stride;
165    }
166}
167
168//FIXME this table is a duplicate from h264data.h, and will be removed once the tables from, h264 have been split
169static const uint8_t scan8[16 + 2*4]={
170 4+1*8, 5+1*8, 4+2*8, 5+2*8,
171 6+1*8, 7+1*8, 6+2*8, 7+2*8,
172 4+3*8, 5+3*8, 4+4*8, 5+4*8,
173 6+3*8, 7+3*8, 6+4*8, 7+4*8,
174 1+1*8, 2+1*8,
175 1+2*8, 2+2*8,
176 1+4*8, 2+4*8,
177 1+5*8, 2+5*8,
178};
179
180void ff_h264_idct_add16_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
181    int i;
182    for(i=0; i<16; i++){
183        int nnz = nnzc[ scan8[i] ];
184        if(nnz){
185            if(nnz==1 && block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
186            else                      idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
187        }
188    }
189}
190
191void ff_h264_idct_add16intra_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
192    int i;
193    for(i=0; i<16; i++){
194        if(nnzc[ scan8[i] ]) idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
195        else if(block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
196    }
197}
198
199void ff_h264_idct8_add4_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
200    int i;
201    for(i=0; i<16; i+=4){
202        int nnz = nnzc[ scan8[i] ];
203        if(nnz){
204            if(nnz==1 && block[i*16]) ff_h264_idct8_dc_add_c(dst + block_offset[i], block + i*16, stride);
205            else                      ff_h264_idct8_add_c   (dst + block_offset[i], block + i*16, stride);
206        }
207    }
208}
209
210void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
211    int i;
212    for(i=16; i<16+8; i++){
213        if(nnzc[ scan8[i] ])
214            ff_h264_idct_add_c   (dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
215        else if(block[i*16])
216            ff_h264_idct_dc_add_c(dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
217    }
218}
219