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| 1 : | Isibaar | 1.1 | /* idct.c, inverse fast discrete cosine transform */ |
| 2 : | |||
| 3 : | /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ | ||
| 4 : | |||
| 5 : | /* | ||
| 6 : | * Disclaimer of Warranty | ||
| 7 : | * | ||
| 8 : | * These software programs are available to the user without any license fee or | ||
| 9 : | * royalty on an "as is" basis. The MPEG Software Simulation Group disclaims | ||
| 10 : | * any and all warranties, whether express, implied, or statuary, including any | ||
| 11 : | * implied warranties or merchantability or of fitness for a particular | ||
| 12 : | * purpose. In no event shall the copyright-holder be liable for any | ||
| 13 : | * incidental, punitive, or consequential damages of any kind whatsoever | ||
| 14 : | * arising from the use of these programs. | ||
| 15 : | * | ||
| 16 : | * This disclaimer of warranty extends to the user of these programs and user's | ||
| 17 : | * customers, employees, agents, transferees, successors, and assigns. | ||
| 18 : | * | ||
| 19 : | * The MPEG Software Simulation Group does not represent or warrant that the | ||
| 20 : | * programs furnished hereunder are free of infringement of any third-party | ||
| 21 : | * patents. | ||
| 22 : | * | ||
| 23 : | * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, | ||
| 24 : | * are subject to royalty fees to patent holders. Many of these patents are | ||
| 25 : | * general enough such that they are unavoidable regardless of implementation | ||
| 26 : | * design. | ||
| 27 : | * | ||
| 28 : | * MPEG2AVI | ||
| 29 : | * -------- | ||
| 30 : | * v0.16B33 renamed the initialization function to init_idct_int32() | ||
| 31 : | * v0.16B32 removed the unused idct_row() and idct_col() functions | ||
| 32 : | * v0.16B3 changed var declarations to static, to enforce data align | ||
| 33 : | * v0.16B22 idct_FAST() renamed to idct_int32() | ||
| 34 : | * also merged idct_FAST() into a single function, to help VC++ | ||
| 35 : | * optimize it. | ||
| 36 : | * | ||
| 37 : | * v0.14 changed int to long, to avoid confusion when compiling on x86 | ||
| 38 : | * platform ( in VC++ "int" -> 32bits ) | ||
| 39 : | */ | ||
| 40 : | |||
| 41 : | /**********************************************************/ | ||
| 42 : | /* inverse two dimensional DCT, Chen-Wang algorithm */ | ||
| 43 : | /* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984) */ | ||
| 44 : | /* 32-bit integer arithmetic (8 bit coefficients) */ | ||
| 45 : | /* 11 mults, 29 adds per DCT */ | ||
| 46 : | /* sE, 18.8.91 */ | ||
| 47 : | /**********************************************************/ | ||
| 48 : | /* coefficients extended to 12 bit for IEEE1180-1990 */ | ||
| 49 : | /* compliance sE, 2.1.94 */ | ||
| 50 : | /**********************************************************/ | ||
| 51 : | |||
| 52 : | /* this code assumes >> to be a two's-complement arithmetic */ | ||
| 53 : | /* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ | ||
| 54 : | |||
| 55 : | //#include <windows.h> | ||
| 56 : | #include "idct.h" | ||
| 57 : | |||
| 58 : | edgomez | 1.2 | #define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */ |
| 59 : | #define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */ | ||
| 60 : | #define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */ | ||
| 61 : | #define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */ | ||
| 62 : | #define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */ | ||
| 63 : | #define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */ | ||
| 64 : | Isibaar | 1.1 | |
| 65 : | |||
| 66 : | /* global declarations */ | ||
| 67 : | //void init_idct_int32 (void); | ||
| 68 : | //void idct_int32 (short *block); | ||
| 69 : | |||
| 70 : | /* private data */ | ||
| 71 : | edgomez | 1.2 | static short iclip[1024]; /* clipping table */ |
| 72 : | Isibaar | 1.1 | static short *iclp; |
| 73 : | |||
| 74 : | /* private prototypes */ | ||
| 75 : | //static void idctrow _ANSI_ARGS_((short *blk)); | ||
| 76 : | //static void idctcol _ANSI_ARGS_((short *blk)); | ||
| 77 : | |||
| 78 : | /* row (horizontal) IDCT | ||
| 79 : | * | ||
| 80 : | * 7 pi 1 | ||
| 81 : | * dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l ) | ||
| 82 : | * l=0 8 2 | ||
| 83 : | * | ||
| 84 : | * where: c[0] = 128 | ||
| 85 : | * c[1..7] = 128*sqrt(2) | ||
| 86 : | */ | ||
| 87 : | |||
| 88 : | /* | ||
| 89 : | static void idctrow(blk) | ||
| 90 : | short *blk; | ||
| 91 : | { | ||
| 92 : | int X0, X1, X2, X3, X4, X5, X6, X7, X8; | ||
| 93 : | |||
| 94 : | // shortcut | ||
| 95 : | if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) | | ||
| 96 : | (X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3]))) | ||
| 97 : | { | ||
| 98 : | blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3; | ||
| 99 : | return; | ||
| 100 : | } | ||
| 101 : | |||
| 102 : | X0 = (blk[0]<<11) + 128; // for proper rounding in the fourth stage | ||
| 103 : | |||
| 104 : | // first stage | ||
| 105 : | X8 = W7*(X4+X5); | ||
| 106 : | X4 = X8 + (W1-W7)*X4; | ||
| 107 : | X5 = X8 - (W1+W7)*X5; | ||
| 108 : | X8 = W3*(X6+X7); | ||
| 109 : | X6 = X8 - (W3-W5)*X6; | ||
| 110 : | X7 = X8 - (W3+W5)*X7; | ||
| 111 : | |||
| 112 : | // second stage | ||
| 113 : | X8 = X0 + X1; | ||
| 114 : | X0 -= X1; | ||
| 115 : | X1 = W6*(X3+X2); | ||
| 116 : | X2 = X1 - (W2+W6)*X2; | ||
| 117 : | X3 = X1 + (W2-W6)*X3; | ||
| 118 : | X1 = X4 + X6; | ||
| 119 : | X4 -= X6; | ||
| 120 : | X6 = X5 + X7; | ||
| 121 : | X5 -= X7; | ||
| 122 : | |||
| 123 : | // third stage | ||
| 124 : | X7 = X8 + X3; | ||
| 125 : | X8 -= X3; | ||
| 126 : | X3 = X0 + X2; | ||
| 127 : | X0 -= X2; | ||
| 128 : | X2 = (181*(X4+X5)+128)>>8; | ||
| 129 : | X4 = (181*(X4-X5)+128)>>8; | ||
| 130 : | |||
| 131 : | // fourth stage | ||
| 132 : | blk[0] = (X7+X1)>>8; | ||
| 133 : | blk[1] = (X3+X2)>>8; | ||
| 134 : | blk[2] = (X0+X4)>>8; | ||
| 135 : | blk[3] = (X8+X6)>>8; | ||
| 136 : | blk[4] = (X8-X6)>>8; | ||
| 137 : | blk[5] = (X0-X4)>>8; | ||
| 138 : | blk[6] = (X3-X2)>>8; | ||
| 139 : | blk[7] = (X7-X1)>>8; | ||
| 140 : | }*/ | ||
| 141 : | |||
| 142 : | /* column (vertical) IDCT | ||
| 143 : | * | ||
| 144 : | * 7 pi 1 | ||
| 145 : | * dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l ) | ||
| 146 : | * l=0 8 2 | ||
| 147 : | * | ||
| 148 : | * where: c[0] = 1/1024 | ||
| 149 : | * c[1..7] = (1/1024)*sqrt(2) | ||
| 150 : | */ | ||
| 151 : | /* | ||
| 152 : | static void idctcol(blk) | ||
| 153 : | short *blk; | ||
| 154 : | { | ||
| 155 : | int X0, X1, X2, X3, X4, X5, X6, X7, X8; | ||
| 156 : | |||
| 157 : | // shortcut | ||
| 158 : | if (!((X1 = (blk[8*4]<<8)) | (X2 = blk[8*6]) | (X3 = blk[8*2]) | | ||
| 159 : | (X4 = blk[8*1]) | (X5 = blk[8*7]) | (X6 = blk[8*5]) | (X7 = blk[8*3]))) | ||
| 160 : | { | ||
| 161 : | blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]=blk[8*5]=blk[8*6]=blk[8*7]= | ||
| 162 : | iclp[(blk[8*0]+32)>>6]; | ||
| 163 : | return; | ||
| 164 : | } | ||
| 165 : | |||
| 166 : | X0 = (blk[8*0]<<8) + 8192; | ||
| 167 : | |||
| 168 : | // first stage | ||
| 169 : | X8 = W7*(X4+X5) + 4; | ||
| 170 : | X4 = (X8+(W1-W7)*X4)>>3; | ||
| 171 : | X5 = (X8-(W1+W7)*X5)>>3; | ||
| 172 : | X8 = W3*(X6+X7) + 4; | ||
| 173 : | X6 = (X8-(W3-W5)*X6)>>3; | ||
| 174 : | X7 = (X8-(W3+W5)*X7)>>3; | ||
| 175 : | |||
| 176 : | // second stage | ||
| 177 : | X8 = X0 + X1; | ||
| 178 : | X0 -= X1; | ||
| 179 : | X1 = W6*(X3+X2) + 4; | ||
| 180 : | X2 = (X1-(W2+W6)*X2)>>3; | ||
| 181 : | X3 = (X1+(W2-W6)*X3)>>3; | ||
| 182 : | X1 = X4 + X6; | ||
| 183 : | X4 -= X6; | ||
| 184 : | X6 = X5 + X7; | ||
| 185 : | X5 -= X7; | ||
| 186 : | |||
| 187 : | // third stage | ||
| 188 : | X7 = X8 + X3; | ||
| 189 : | X8 -= X3; | ||
| 190 : | X3 = X0 + X2; | ||
| 191 : | X0 -= X2; | ||
| 192 : | X2 = (181*(X4+X5)+128)>>8; | ||
| 193 : | X4 = (181*(X4-X5)+128)>>8; | ||
| 194 : | |||
| 195 : | // fourth stage | ||
| 196 : | blk[8*0] = iclp[(X7+X1)>>14]; | ||
| 197 : | blk[8*1] = iclp[(X3+X2)>>14]; | ||
| 198 : | blk[8*2] = iclp[(X0+X4)>>14]; | ||
| 199 : | blk[8*3] = iclp[(X8+X6)>>14]; | ||
| 200 : | blk[8*4] = iclp[(X8-X6)>>14]; | ||
| 201 : | blk[8*5] = iclp[(X0-X4)>>14]; | ||
| 202 : | blk[8*6] = iclp[(X3-X2)>>14]; | ||
| 203 : | blk[8*7] = iclp[(X7-X1)>>14]; | ||
| 204 : | }*/ | ||
| 205 : | |||
| 206 : | // function pointer | ||
| 207 : | idctFuncPtr idct; | ||
| 208 : | |||
| 209 : | /* two dimensional inverse discrete cosine transform */ | ||
| 210 : | //void j_rev_dct(block) | ||
| 211 : | //short *block; | ||
| 212 : | edgomez | 1.2 | void |
| 213 : | idct_int32(short *const block) | ||
| 214 : | Isibaar | 1.1 | { |
| 215 : | |||
| 216 : | edgomez | 1.2 | // idct_int32_init() must be called before the first call to this function! |
| 217 : | Isibaar | 1.1 | |
| 218 : | |||
| 219 : | edgomez | 1.2 | /*int i; |
| 220 : | long i; | ||
| 221 : | Isibaar | 1.1 | |
| 222 : | edgomez | 1.2 | for (i=0; i<8; i++) |
| 223 : | idctrow(block+8*i); | ||
| 224 : | Isibaar | 1.1 | |
| 225 : | edgomez | 1.2 | for (i=0; i<8; i++) |
| 226 : | idctcol(block+i); */ | ||
| 227 : | static short *blk; | ||
| 228 : | static long i; | ||
| 229 : | static long X0, X1, X2, X3, X4, X5, X6, X7, X8; | ||
| 230 : | Isibaar | 1.1 | |
| 231 : | |||
| 232 : | edgomez | 1.2 | for (i = 0; i < 8; i++) // idct rows |
| 233 : | Isibaar | 1.1 | { |
| 234 : | edgomez | 1.2 | blk = block + (i << 3); |
| 235 : | if (! | ||
| 236 : | ((X1 = blk[4] << 11) | (X2 = blk[6]) | (X3 = blk[2]) | (X4 = | ||
| 237 : | blk[1]) | | ||
| 238 : | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3]))) { | ||
| 239 : | blk[0] = blk[1] = blk[2] = blk[3] = blk[4] = blk[5] = blk[6] = | ||
| 240 : | blk[7] = blk[0] << 3; | ||
| 241 : | continue; | ||
| 242 : | } | ||
| 243 : | |||
| 244 : | X0 = (blk[0] << 11) + 128; // for proper rounding in the fourth stage | ||
| 245 : | |||
| 246 : | // first stage | ||
| 247 : | X8 = W7 * (X4 + X5); | ||
| 248 : | X4 = X8 + (W1 - W7) * X4; | ||
| 249 : | X5 = X8 - (W1 + W7) * X5; | ||
| 250 : | X8 = W3 * (X6 + X7); | ||
| 251 : | X6 = X8 - (W3 - W5) * X6; | ||
| 252 : | X7 = X8 - (W3 + W5) * X7; | ||
| 253 : | |||
| 254 : | // second stage | ||
| 255 : | X8 = X0 + X1; | ||
| 256 : | X0 -= X1; | ||
| 257 : | X1 = W6 * (X3 + X2); | ||
| 258 : | X2 = X1 - (W2 + W6) * X2; | ||
| 259 : | X3 = X1 + (W2 - W6) * X3; | ||
| 260 : | X1 = X4 + X6; | ||
| 261 : | X4 -= X6; | ||
| 262 : | X6 = X5 + X7; | ||
| 263 : | X5 -= X7; | ||
| 264 : | |||
| 265 : | // third stage | ||
| 266 : | X7 = X8 + X3; | ||
| 267 : | X8 -= X3; | ||
| 268 : | X3 = X0 + X2; | ||
| 269 : | X0 -= X2; | ||
| 270 : | X2 = (181 * (X4 + X5) + 128) >> 8; | ||
| 271 : | X4 = (181 * (X4 - X5) + 128) >> 8; | ||
| 272 : | |||
| 273 : | // fourth stage | ||
| 274 : | |||
| 275 : | blk[0] = (short) ((X7 + X1) >> 8); | ||
| 276 : | blk[1] = (short) ((X3 + X2) >> 8); | ||
| 277 : | blk[2] = (short) ((X0 + X4) >> 8); | ||
| 278 : | blk[3] = (short) ((X8 + X6) >> 8); | ||
| 279 : | blk[4] = (short) ((X8 - X6) >> 8); | ||
| 280 : | blk[5] = (short) ((X0 - X4) >> 8); | ||
| 281 : | blk[6] = (short) ((X3 - X2) >> 8); | ||
| 282 : | blk[7] = (short) ((X7 - X1) >> 8); | ||
| 283 : | Isibaar | 1.1 | |
| 284 : | edgomez | 1.2 | } // end for ( i = 0; i < 8; ++i ) IDCT-rows |
| 285 : | Isibaar | 1.1 | |
| 286 : | |||
| 287 : | |||
| 288 : | edgomez | 1.2 | for (i = 0; i < 8; i++) // idct columns |
| 289 : | Isibaar | 1.1 | { |
| 290 : | edgomez | 1.2 | blk = block + i; |
| 291 : | // shortcut | ||
| 292 : | if (! | ||
| 293 : | ((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 = | ||
| 294 : | blk[8 * | ||
| 295 : | 2]) | (X4 = | ||
| 296 : | blk[8 * | ||
| 297 : | 1]) | ||
| 298 : | | (X5 = blk[8 * 7]) | (X6 = blk[8 * 5]) | (X7 = blk[8 * 3]))) { | ||
| 299 : | blk[8 * 0] = blk[8 * 1] = blk[8 * 2] = blk[8 * 3] = blk[8 * 4] = | ||
| 300 : | blk[8 * 5] = blk[8 * 6] = blk[8 * 7] = | ||
| 301 : | iclp[(blk[8 * 0] + 32) >> 6]; | ||
| 302 : | continue; | ||
| 303 : | } | ||
| 304 : | |||
| 305 : | X0 = (blk[8 * 0] << 8) + 8192; | ||
| 306 : | |||
| 307 : | // first stage | ||
| 308 : | X8 = W7 * (X4 + X5) + 4; | ||
| 309 : | X4 = (X8 + (W1 - W7) * X4) >> 3; | ||
| 310 : | X5 = (X8 - (W1 + W7) * X5) >> 3; | ||
| 311 : | X8 = W3 * (X6 + X7) + 4; | ||
| 312 : | X6 = (X8 - (W3 - W5) * X6) >> 3; | ||
| 313 : | X7 = (X8 - (W3 + W5) * X7) >> 3; | ||
| 314 : | |||
| 315 : | // second stage | ||
| 316 : | X8 = X0 + X1; | ||
| 317 : | X0 -= X1; | ||
| 318 : | X1 = W6 * (X3 + X2) + 4; | ||
| 319 : | X2 = (X1 - (W2 + W6) * X2) >> 3; | ||
| 320 : | X3 = (X1 + (W2 - W6) * X3) >> 3; | ||
| 321 : | X1 = X4 + X6; | ||
| 322 : | X4 -= X6; | ||
| 323 : | X6 = X5 + X7; | ||
| 324 : | X5 -= X7; | ||
| 325 : | |||
| 326 : | // third stage | ||
| 327 : | X7 = X8 + X3; | ||
| 328 : | X8 -= X3; | ||
| 329 : | X3 = X0 + X2; | ||
| 330 : | X0 -= X2; | ||
| 331 : | X2 = (181 * (X4 + X5) + 128) >> 8; | ||
| 332 : | X4 = (181 * (X4 - X5) + 128) >> 8; | ||
| 333 : | |||
| 334 : | // fourth stage | ||
| 335 : | blk[8 * 0] = iclp[(X7 + X1) >> 14]; | ||
| 336 : | blk[8 * 1] = iclp[(X3 + X2) >> 14]; | ||
| 337 : | blk[8 * 2] = iclp[(X0 + X4) >> 14]; | ||
| 338 : | blk[8 * 3] = iclp[(X8 + X6) >> 14]; | ||
| 339 : | blk[8 * 4] = iclp[(X8 - X6) >> 14]; | ||
| 340 : | blk[8 * 5] = iclp[(X0 - X4) >> 14]; | ||
| 341 : | blk[8 * 6] = iclp[(X3 - X2) >> 14]; | ||
| 342 : | blk[8 * 7] = iclp[(X7 - X1) >> 14]; | ||
| 343 : | Isibaar | 1.1 | } |
| 344 : | |||
| 345 : | edgomez | 1.2 | } // end function idct_int32(block) |
| 346 : | Isibaar | 1.1 | |
| 347 : | |||
| 348 : | //void | ||
| 349 : | //idct_int32_init() | ||
| 350 : | edgomez | 1.2 | void |
| 351 : | idct_int32_init() | ||
| 352 : | Isibaar | 1.1 | { |
| 353 : | edgomez | 1.2 | int i; |
| 354 : | Isibaar | 1.1 | |
| 355 : | edgomez | 1.2 | iclp = iclip + 512; |
| 356 : | for (i = -512; i < 512; i++) | ||
| 357 : | iclp[i] = (i < -256) ? -256 : ((i > 255) ? 255 : i); | ||
| 358 : | Isibaar | 1.1 | } |
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