ffmpeg/libavcodec/simple_idct.c

   1 /*
   2  * Simple IDCT
   3  *
   4  * Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file
  25  * simpleidct in C.
  26  */
  27
  28 #include "libavutil/intreadwrite.h"
  29 #include "avcodec.h"
  30 #include "mathops.h"
  31 #include "simple_idct.h"
  32
  33 #define BIT_DEPTH 8
  34 #include "simple_idct_template.c"
  35 #undef BIT_DEPTH
  36
  37 #define BIT_DEPTH 10
  38 #include "simple_idct_template.c"
  39 #undef BIT_DEPTH
  40
  41 #define BIT_DEPTH 12
  42 #include "simple_idct_template.c"
  43 #undef BIT_DEPTH
  44
  45 /* 2x4x8 idct */
  46
  47 #define CN_SHIFT 12
  48 #define C_FIX(x) ((int)((x) * (1 << CN_SHIFT) + 0.5))
  49 #define C1 C_FIX(0.6532814824)
  50 #define C2 C_FIX(0.2705980501)
  51
  52 /* row idct is multiple by 16 * sqrt(2.0), col idct4 is normalized,
  53    and the butterfly must be multiplied by 0.5 * sqrt(2.0) */
  54 #define C_SHIFT (4+1+12)
  55
  56 static inline void idct4col_put(uint8_t *dest, int line_size, const int16_t *col)
  57 {
  58     int c0, c1, c2, c3, a0, a1, a2, a3;
  59
  60     a0 = col[8*0];
  61     a1 = col[8*2];
  62     a2 = col[8*4];
  63     a3 = col[8*6];
  64     c0 = ((a0 + a2) << (CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
  65     c2 = ((a0 - a2) << (CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
  66     c1 = a1 * C1 + a3 * C2;
  67     c3 = a1 * C2 - a3 * C1;
  68     dest[0] = av_clip_uint8((c0 + c1) >> C_SHIFT);
  69     dest += line_size;
  70     dest[0] = av_clip_uint8((c2 + c3) >> C_SHIFT);
  71     dest += line_size;
  72     dest[0] = av_clip_uint8((c2 - c3) >> C_SHIFT);
  73     dest += line_size;
  74     dest[0] = av_clip_uint8((c0 - c1) >> C_SHIFT);
  75 }
  76
  77 #define BF(k) \
  78 {\
  79     int a0, a1;\
  80     a0 = ptr[k];\
  81     a1 = ptr[8 + k];\
  82     ptr[k] = a0 + a1;\
  83     ptr[8 + k] = a0 - a1;\
  84 }
  85
  86 /* only used by DV codec. The input must be interlaced. 128 is added
  87    to the pixels before clamping to avoid systematic error
  88    (1024*sqrt(2)) offset would be needed otherwise. */
  89 /* XXX: I think a 1.0/sqrt(2) normalization should be needed to
  90    compensate the extra butterfly stage - I don't have the full DV
  91    specification */
  92 void ff_simple_idct248_put(uint8_t *dest, int line_size, int16_t *block)
  93 {
  94     int i;
  95     int16_t *ptr;
  96
  97     /* butterfly */
  98     ptr = block;
  99     for(i=0;i<4;i++) {
 100         BF(0);
 101         BF(1);
 102         BF(2);
 103         BF(3);
 104         BF(4);
 105         BF(5);
 106         BF(6);
 107         BF(7);
 108         ptr += 2 * 8;
 109     }
 110
 111     /* IDCT8 on each line */
 112     for(i=0; i<8; i++) {
 113         idctRowCondDC_8(block + i*8, 0);
 114     }
 115
 116     /* IDCT4 and store */
 117     for(i=0;i<8;i++) {
 118         idct4col_put(dest + i, 2 * line_size, block + i);
 119         idct4col_put(dest + line_size + i, 2 * line_size, block + 8 + i);
 120     }
 121 }
 122
 123 /* 8x4 & 4x8 WMV2 IDCT */
 124 #undef CN_SHIFT
 125 #undef C_SHIFT
 126 #undef C_FIX
 127 #undef C1
 128 #undef C2
 129 #define CN_SHIFT 12
 130 #define C_FIX(x) ((int)((x) * 1.414213562 * (1 << CN_SHIFT) + 0.5))
 131 #define C1 C_FIX(0.6532814824)
 132 #define C2 C_FIX(0.2705980501)
 133 #define C3 C_FIX(0.5)
 134 #define C_SHIFT (4+1+12)
 135 static inline void idct4col_add(uint8_t *dest, int line_size, const int16_t *col)
 136 {
 137     int c0, c1, c2, c3, a0, a1, a2, a3;
 138
 139     a0 = col[8*0];
 140     a1 = col[8*1];
 141     a2 = col[8*2];
 142     a3 = col[8*3];
 143     c0 = (a0 + a2)*C3 + (1 << (C_SHIFT - 1));
 144     c2 = (a0 - a2)*C3 + (1 << (C_SHIFT - 1));
 145     c1 = a1 * C1 + a3 * C2;
 146     c3 = a1 * C2 - a3 * C1;
 147     dest[0] = av_clip_uint8(dest[0] + ((c0 + c1) >> C_SHIFT));
 148     dest += line_size;
 149     dest[0] = av_clip_uint8(dest[0] + ((c2 + c3) >> C_SHIFT));
 150     dest += line_size;
 151     dest[0] = av_clip_uint8(dest[0] + ((c2 - c3) >> C_SHIFT));
 152     dest += line_size;
 153     dest[0] = av_clip_uint8(dest[0] + ((c0 - c1) >> C_SHIFT));
 154 }
 155
 156 #define RN_SHIFT 15
 157 #define R_FIX(x) ((int)((x) * 1.414213562 * (1 << RN_SHIFT) + 0.5))
 158 #define R1 R_FIX(0.6532814824)
 159 #define R2 R_FIX(0.2705980501)
 160 #define R3 R_FIX(0.5)
 161 #define R_SHIFT 11
 162 static inline void idct4row(int16_t *row)
 163 {
 164     int c0, c1, c2, c3, a0, a1, a2, a3;
 165
 166     a0 = row[0];
 167     a1 = row[1];
 168     a2 = row[2];
 169     a3 = row[3];
 170     c0 = (a0 + a2)*R3 + (1 << (R_SHIFT - 1));
 171     c2 = (a0 - a2)*R3 + (1 << (R_SHIFT - 1));
 172     c1 = a1 * R1 + a3 * R2;
 173     c3 = a1 * R2 - a3 * R1;
 174     row[0]= (c0 + c1) >> R_SHIFT;
 175     row[1]= (c2 + c3) >> R_SHIFT;
 176     row[2]= (c2 - c3) >> R_SHIFT;
 177     row[3]= (c0 - c1) >> R_SHIFT;
 178 }
 179
 180 void ff_simple_idct84_add(uint8_t *dest, int line_size, int16_t *block)
 181 {
 182     int i;
 183
 184     /* IDCT8 on each line */
 185     for(i=0; i<4; i++) {
 186         idctRowCondDC_8(block + i*8, 0);
 187     }
 188
 189     /* IDCT4 and store */
 190     for(i=0;i<8;i++) {
 191         idct4col_add(dest + i, line_size, block + i);
 192     }
 193 }
 194
 195 void ff_simple_idct48_add(uint8_t *dest, int line_size, int16_t *block)
 196 {
 197     int i;
 198
 199     /* IDCT4 on each line */
 200     for(i=0; i<8; i++) {
 201         idct4row(block + i*8);
 202     }
 203
 204     /* IDCT8 and store */
 205     for(i=0; i<4; i++){
 206         idctSparseColAdd_8(dest + i, line_size, block + i);
 207     }
 208 }
 209
 210 void ff_simple_idct44_add(uint8_t *dest, int line_size, int16_t *block)
 211 {
 212     int i;
 213
 214     /* IDCT4 on each line */
 215     for(i=0; i<4; i++) {
 216         idct4row(block + i*8);
 217     }
 218
 219     /* IDCT4 and store */
 220     for(i=0; i<4; i++){
 221         idct4col_add(dest + i, line_size, block + i);
 222     }
 223 }
 224
 225 void ff_prores_idct(int16_t *block, const int16_t *qmat)
 226 {
 227     int i;
 228
 229     for (i = 0; i < 64; i++)
 230         block[i] *= qmat[i];
 231
 232     for (i = 0; i < 8; i++)
 233         idctRowCondDC_10(block + i*8, 2);
 234
 235     for (i = 0; i < 8; i++) {
 236         block[i] += 8192;
 237         idctSparseCol_10(block + i);
 238     }
 239 }