| 1 |
/* |
| 2 |
* jrevdct.c |
| 3 |
* |
| 4 |
* Copyright (C) 1991, 1992, Thomas G. Lane. |
| 5 |
* This file is part of the Independent JPEG Group's software. |
| 6 |
* For conditions of distribution and use, see the accompanying README file. |
| 7 |
* |
| 8 |
* This file contains the basic inverse-DCT transformation subroutine. |
| 9 |
* |
| 10 |
* This implementation is based on an algorithm described in |
| 11 |
* C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT |
| 12 |
* Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics, |
| 13 |
* Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991. |
| 14 |
* The primary algorithm described there uses 11 multiplies and 29 adds. |
| 15 |
* We use their alternate method with 12 multiplies and 32 adds. |
| 16 |
* The advantage of this method is that no data path contains more than one |
| 17 |
* multiplication; this allows a very simple and accurate implementation in |
| 18 |
* scaled fixed-point arithmetic, with a minimal number of shifts. |
| 19 |
* |
| 20 |
* I've made lots of modifications to attempt to take advantage of the |
| 21 |
* sparse nature of the DCT matrices we're getting. Although the logic |
| 22 |
* is cumbersome, it's straightforward and the resulting code is much |
| 23 |
* faster. |
| 24 |
* |
| 25 |
* A better way to do this would be to pass in the DCT block as a sparse |
| 26 |
* matrix, perhaps with the difference cases encoded. |
| 27 |
*/ |
| 28 |
|
| 29 |
#include <memory.h> |
| 30 |
#include "all.h" |
| 31 |
#include "ansi.h" |
| 32 |
#include "dct.h" |
| 33 |
|
| 34 |
|
| 35 |
#define CONST_BITS 13 |
| 36 |
|
| 37 |
/* |
| 38 |
* This routine is specialized to the case DCTSIZE = 8. |
| 39 |
*/ |
| 40 |
|
| 41 |
#if DCTSIZE != 8 |
| 42 |
Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ |
| 43 |
#endif |
| 44 |
|
| 45 |
|
| 46 |
/* |
| 47 |
* A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT |
| 48 |
* on each column. Direct algorithms are also available, but they are |
| 49 |
* much more complex and seem not to be any faster when reduced to code. |
| 50 |
* |
| 51 |
* The poop on this scaling stuff is as follows: |
| 52 |
* |
| 53 |
* Each 1-D IDCT step produces outputs which are a factor of sqrt(N) |
| 54 |
* larger than the true IDCT outputs. The final outputs are therefore |
| 55 |
* a factor of N larger than desired; since N=8 this can be cured by |
| 56 |
* a simple right shift at the end of the algorithm. The advantage of |
| 57 |
* this arrangement is that we save two multiplications per 1-D IDCT, |
| 58 |
* because the y0 and y4 inputs need not be divided by sqrt(N). |
| 59 |
* |
| 60 |
* We have to do addition and subtraction of the integer inputs, which |
| 61 |
* is no problem, and multiplication by fractional constants, which is |
| 62 |
* a problem to do in integer arithmetic. We multiply all the constants |
| 63 |
* by CONST_SCALE and convert them to integer constants (thus retaining |
| 64 |
* CONST_BITS bits of precision in the constants). After doing a |
| 65 |
* multiplication we have to divide the product by CONST_SCALE, with proper |
| 66 |
* rounding, to produce the correct output. This division can be done |
| 67 |
* cheaply as a right shift of CONST_BITS bits. We postpone shifting |
| 68 |
* as long as possible so that partial sums can be added together with |
| 69 |
* full fractional precision. |
| 70 |
* |
| 71 |
* The outputs of the first pass are scaled up by PASS1_BITS bits so that |
| 72 |
* they are represented to better-than-integral precision. These outputs |
| 73 |
* require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word |
| 74 |
* with the recommended scaling. (To scale up 12-bit sample data further, an |
| 75 |
* intermediate int32 array would be needed.) |
| 76 |
* |
| 77 |
* To avoid overflow of the 32-bit intermediate results in pass 2, we must |
| 78 |
* have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis |
| 79 |
* shows that the values given below are the most effective. |
| 80 |
*/ |
| 81 |
|
| 82 |
#ifdef EIGHT_BIT_SAMPLES |
| 83 |
#define PASS1_BITS 2 |
| 84 |
#else |
| 85 |
#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ |
| 86 |
#endif |
| 87 |
|
| 88 |
#define ONE ((int32) 1) |
| 89 |
|
| 90 |
#define CONST_SCALE (ONE << CONST_BITS) |
| 91 |
|
| 92 |
/* Convert a positive real constant to an integer scaled by CONST_SCALE. |
| 93 |
* IMPORTANT: if your compiler doesn't do this arithmetic at compile time, |
| 94 |
* you will pay a significant penalty in run time. In that case, figure |
| 95 |
* the correct integer constant values and insert them by hand. |
| 96 |
*/ |
| 97 |
|
| 98 |
/* Actually FIX is no longer used, we precomputed them all */ |
| 99 |
#define FIX(x) ((int32) ((x) * CONST_SCALE + 0.5)) |
| 100 |
|
| 101 |
/* Descale and correctly round an int32 value that's scaled by N bits. |
| 102 |
* We assume RIGHT_SHIFT rounds towards minus infinity, so adding |
| 103 |
* the fudge factor is correct for either sign of X. |
| 104 |
*/ |
| 105 |
|
| 106 |
#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) |
| 107 |
|
| 108 |
/* Multiply an int32 variable by an int32 constant to yield an int32 result. |
| 109 |
* For 8-bit samples with the recommended scaling, all the variable |
| 110 |
* and constant values involved are no more than 16 bits wide, so a |
| 111 |
* 16x16->32 bit multiply can be used instead of a full 32x32 multiply; |
| 112 |
* this provides a useful speedup on many machines. |
| 113 |
* There is no way to specify a 16x16->32 multiply in portable C, but |
| 114 |
* some C compilers will do the right thing if you provide the correct |
| 115 |
* combination of casts. |
| 116 |
* NB: for 12-bit samples, a full 32-bit multiplication will be needed. |
| 117 |
*/ |
| 118 |
|
| 119 |
#ifdef EIGHT_BIT_SAMPLES |
| 120 |
#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ |
| 121 |
#define MULTIPLY(var,const) (((INT16) (var)) * ((INT16) (const))) |
| 122 |
#endif |
| 123 |
#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ |
| 124 |
#define MULTIPLY(var,const) (((INT16) (var)) * ((int32) (const))) |
| 125 |
#endif |
| 126 |
#endif |
| 127 |
|
| 128 |
#ifndef MULTIPLY /* default definition */ |
| 129 |
#define MULTIPLY(var,const) ((var) * (const)) |
| 130 |
#endif |
| 131 |
|
| 132 |
|
| 133 |
/* |
| 134 |
Unlike our decoder where we approximate the FIXes, we need to use exact |
| 135 |
ones here or successive P-frames will drift too much with Reference frame coding |
| 136 |
*/ |
| 137 |
#define FIX_0_211164243 1730 |
| 138 |
#define FIX_0_275899380 2260 |
| 139 |
#define FIX_0_298631336 2446 |
| 140 |
#define FIX_0_390180644 3196 |
| 141 |
#define FIX_0_509795579 4176 |
| 142 |
#define FIX_0_541196100 4433 |
| 143 |
#define FIX_0_601344887 4926 |
| 144 |
#define FIX_0_765366865 6270 |
| 145 |
#define FIX_0_785694958 6436 |
| 146 |
#define FIX_0_899976223 7373 |
| 147 |
#define FIX_1_061594337 8697 |
| 148 |
#define FIX_1_111140466 9102 |
| 149 |
#define FIX_1_175875602 9633 |
| 150 |
#define FIX_1_306562965 10703 |
| 151 |
#define FIX_1_387039845 11363 |
| 152 |
#define FIX_1_451774981 11893 |
| 153 |
#define FIX_1_501321110 12299 |
| 154 |
#define FIX_1_662939225 13623 |
| 155 |
#define FIX_1_847759065 15137 |
| 156 |
#define FIX_1_961570560 16069 |
| 157 |
#define FIX_2_053119869 16819 |
| 158 |
#define FIX_2_172734803 17799 |
| 159 |
#define FIX_2_562915447 20995 |
| 160 |
#define FIX_3_072711026 25172 |
| 161 |
|
| 162 |
/* |
| 163 |
Switch on reverse_dct choices |
| 164 |
*/ |
| 165 |
void reference_rev_dct _ANSI_ARGS_((int16 *block)); |
| 166 |
void mpeg_jrevdct_quick _ANSI_ARGS_((int16 *block)); |
| 167 |
void init_idctref _ANSI_ARGS_((void)); |
| 168 |
|
| 169 |
extern boolean pureDCT; |
| 170 |
|
| 171 |
void |
| 172 |
mpeg_jrevdct(data) |
| 173 |
DCTBLOCK data; |
| 174 |
{ |
| 175 |
if (pureDCT) reference_rev_dct(data); |
| 176 |
else mpeg_jrevdct_quick(data); |
| 177 |
} |
| 178 |
|
| 179 |
/* |
| 180 |
* Perform the inverse DCT on one block of coefficients. |
| 181 |
*/ |
| 182 |
|
| 183 |
void |
| 184 |
mpeg_jrevdct_quick(data) |
| 185 |
DCTBLOCK data; |
| 186 |
{ |
| 187 |
int32 tmp0, tmp1, tmp2, tmp3; |
| 188 |
int32 tmp10, tmp11, tmp12, tmp13; |
| 189 |
int32 z1, z2, z3, z4, z5; |
| 190 |
int32 d0, d1, d2, d3, d4, d5, d6, d7; |
| 191 |
register DCTELEM *dataptr; |
| 192 |
int rowctr; |
| 193 |
SHIFT_TEMPS |
| 194 |
|
| 195 |
/* Pass 1: process rows. */ |
| 196 |
/* Note results are scaled up by sqrt(8) compared to a true IDCT; */ |
| 197 |
/* furthermore, we scale the results by 2**PASS1_BITS. */ |
| 198 |
|
| 199 |
dataptr = data; |
| 200 |
|
| 201 |
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { |
| 202 |
/* Due to quantization, we will usually find that many of the input |
| 203 |
* coefficients are zero, especially the AC terms. We can exploit this |
| 204 |
* by short-circuiting the IDCT calculation for any row in which all |
| 205 |
* the AC terms are zero. In that case each output is equal to the |
| 206 |
* DC coefficient (with scale factor as needed). |
| 207 |
* With typical images and quantization tables, half or more of the |
| 208 |
* row DCT calculations can be simplified this way. |
| 209 |
*/ |
| 210 |
|
| 211 |
register int *idataptr = (int*)dataptr; |
| 212 |
d0 = dataptr[0]; |
| 213 |
d1 = dataptr[1]; |
| 214 |
if ((d1 == 0) && (idataptr[1] | idataptr[2] | idataptr[3]) == 0) { |
| 215 |
/* AC terms all zero */ |
| 216 |
if (d0) { |
| 217 |
/* Compute a 32 bit value to assign. */ |
| 218 |
DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS); |
| 219 |
register int v = (dcval & 0xffff) | ((dcval << 16) & 0xffff0000); |
| 220 |
|
| 221 |
idataptr[0] = v; |
| 222 |
idataptr[1] = v; |
| 223 |
idataptr[2] = v; |
| 224 |
idataptr[3] = v; |
| 225 |
} |
| 226 |
|
| 227 |
dataptr += DCTSIZE; /* advance pointer to next row */ |
| 228 |
continue; |
| 229 |
} |
| 230 |
d2 = dataptr[2]; |
| 231 |
d3 = dataptr[3]; |
| 232 |
d4 = dataptr[4]; |
| 233 |
d5 = dataptr[5]; |
| 234 |
d6 = dataptr[6]; |
| 235 |
d7 = dataptr[7]; |
| 236 |
|
| 237 |
/* Even part: reverse the even part of the forward DCT. */ |
| 238 |
/* The rotator is sqrt(2)*c(-6). */ |
| 239 |
{ |
| 240 |
if (d6) { |
| 241 |
if (d4) { |
| 242 |
if (d2) { |
| 243 |
if (d0) { |
| 244 |
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ |
| 245 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 246 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 247 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 248 |
|
| 249 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 250 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 251 |
|
| 252 |
tmp10 = tmp0 + tmp3; |
| 253 |
tmp13 = tmp0 - tmp3; |
| 254 |
tmp11 = tmp1 + tmp2; |
| 255 |
tmp12 = tmp1 - tmp2; |
| 256 |
} else { |
| 257 |
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */ |
| 258 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 259 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 260 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 261 |
|
| 262 |
tmp0 = d4 << CONST_BITS; |
| 263 |
|
| 264 |
tmp10 = tmp0 + tmp3; |
| 265 |
tmp13 = tmp0 - tmp3; |
| 266 |
tmp11 = tmp2 - tmp0; |
| 267 |
tmp12 = -(tmp0 + tmp2); |
| 268 |
} |
| 269 |
} else { |
| 270 |
if (d0) { |
| 271 |
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ |
| 272 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 273 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 274 |
|
| 275 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 276 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 277 |
|
| 278 |
tmp10 = tmp0 + tmp3; |
| 279 |
tmp13 = tmp0 - tmp3; |
| 280 |
tmp11 = tmp1 + tmp2; |
| 281 |
tmp12 = tmp1 - tmp2; |
| 282 |
} else { |
| 283 |
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */ |
| 284 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 285 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 286 |
|
| 287 |
tmp0 = d4 << CONST_BITS; |
| 288 |
|
| 289 |
tmp10 = tmp0 + tmp3; |
| 290 |
tmp13 = tmp0 - tmp3; |
| 291 |
tmp11 = tmp2 - tmp0; |
| 292 |
tmp12 = -(tmp0 + tmp2); |
| 293 |
} |
| 294 |
} |
| 295 |
} else { |
| 296 |
if (d2) { |
| 297 |
if (d0) { |
| 298 |
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */ |
| 299 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 300 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 301 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 302 |
|
| 303 |
tmp0 = d0 << CONST_BITS; |
| 304 |
|
| 305 |
tmp10 = tmp0 + tmp3; |
| 306 |
tmp13 = tmp0 - tmp3; |
| 307 |
tmp11 = tmp0 + tmp2; |
| 308 |
tmp12 = tmp0 - tmp2; |
| 309 |
} else { |
| 310 |
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */ |
| 311 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 312 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 313 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 314 |
|
| 315 |
tmp10 = tmp3; |
| 316 |
tmp13 = -tmp3; |
| 317 |
tmp11 = tmp2; |
| 318 |
tmp12 = -tmp2; |
| 319 |
} |
| 320 |
} else { |
| 321 |
if (d0) { |
| 322 |
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */ |
| 323 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 324 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 325 |
|
| 326 |
tmp0 = d0 << CONST_BITS; |
| 327 |
|
| 328 |
tmp10 = tmp0 + tmp3; |
| 329 |
tmp13 = tmp0 - tmp3; |
| 330 |
tmp11 = tmp0 + tmp2; |
| 331 |
tmp12 = tmp0 - tmp2; |
| 332 |
} else { |
| 333 |
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */ |
| 334 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 335 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 336 |
|
| 337 |
tmp10 = tmp3; |
| 338 |
tmp13 = -tmp3; |
| 339 |
tmp11 = tmp2; |
| 340 |
tmp12 = -tmp2; |
| 341 |
} |
| 342 |
} |
| 343 |
} |
| 344 |
} else { |
| 345 |
if (d4) { |
| 346 |
if (d2) { |
| 347 |
if (d0) { |
| 348 |
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ |
| 349 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 350 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 351 |
|
| 352 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 353 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 354 |
|
| 355 |
tmp10 = tmp0 + tmp3; |
| 356 |
tmp13 = tmp0 - tmp3; |
| 357 |
tmp11 = tmp1 + tmp2; |
| 358 |
tmp12 = tmp1 - tmp2; |
| 359 |
} else { |
| 360 |
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */ |
| 361 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 362 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 363 |
|
| 364 |
tmp0 = d4 << CONST_BITS; |
| 365 |
|
| 366 |
tmp10 = tmp0 + tmp3; |
| 367 |
tmp13 = tmp0 - tmp3; |
| 368 |
tmp11 = tmp2 - tmp0; |
| 369 |
tmp12 = -(tmp0 + tmp2); |
| 370 |
} |
| 371 |
} else { |
| 372 |
if (d0) { |
| 373 |
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ |
| 374 |
tmp10 = tmp13 = (d0 + d4) << CONST_BITS; |
| 375 |
tmp11 = tmp12 = (d0 - d4) << CONST_BITS; |
| 376 |
} else { |
| 377 |
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */ |
| 378 |
tmp10 = tmp13 = d4 << CONST_BITS; |
| 379 |
tmp11 = tmp12 = -tmp10; |
| 380 |
} |
| 381 |
} |
| 382 |
} else { |
| 383 |
if (d2) { |
| 384 |
if (d0) { |
| 385 |
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */ |
| 386 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 387 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 388 |
|
| 389 |
tmp0 = d0 << CONST_BITS; |
| 390 |
|
| 391 |
tmp10 = tmp0 + tmp3; |
| 392 |
tmp13 = tmp0 - tmp3; |
| 393 |
tmp11 = tmp0 + tmp2; |
| 394 |
tmp12 = tmp0 - tmp2; |
| 395 |
} else { |
| 396 |
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */ |
| 397 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 398 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 399 |
|
| 400 |
tmp10 = tmp3; |
| 401 |
tmp13 = -tmp3; |
| 402 |
tmp11 = tmp2; |
| 403 |
tmp12 = -tmp2; |
| 404 |
} |
| 405 |
} else { |
| 406 |
if (d0) { |
| 407 |
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */ |
| 408 |
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS; |
| 409 |
} else { |
| 410 |
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */ |
| 411 |
tmp10 = tmp13 = tmp11 = tmp12 = 0; |
| 412 |
} |
| 413 |
} |
| 414 |
} |
| 415 |
} |
| 416 |
|
| 417 |
/* Odd part per figure 8; the matrix is unitary and hence its |
| 418 |
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. |
| 419 |
*/ |
| 420 |
|
| 421 |
if (d7) { |
| 422 |
if (d5) { |
| 423 |
if (d3) { |
| 424 |
if (d1) { |
| 425 |
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */ |
| 426 |
z1 = d7 + d1; |
| 427 |
z2 = d5 + d3; |
| 428 |
z3 = d7 + d3; |
| 429 |
z4 = d5 + d1; |
| 430 |
z5 = MULTIPLY(z3 + z4, FIX_1_175875602); |
| 431 |
|
| 432 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 433 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 434 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 435 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 436 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 437 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 438 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 439 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 440 |
|
| 441 |
z3 += z5; |
| 442 |
z4 += z5; |
| 443 |
|
| 444 |
tmp0 += z1 + z3; |
| 445 |
tmp1 += z2 + z4; |
| 446 |
tmp2 += z2 + z3; |
| 447 |
tmp3 += z1 + z4; |
| 448 |
} else { |
| 449 |
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */ |
| 450 |
z2 = d5 + d3; |
| 451 |
z3 = d7 + d3; |
| 452 |
z5 = MULTIPLY(z3 + d5, FIX_1_175875602); |
| 453 |
|
| 454 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 455 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 456 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 457 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 458 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 459 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 460 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 461 |
|
| 462 |
z3 += z5; |
| 463 |
z4 += z5; |
| 464 |
|
| 465 |
tmp0 += z1 + z3; |
| 466 |
tmp1 += z2 + z4; |
| 467 |
tmp2 += z2 + z3; |
| 468 |
tmp3 = z1 + z4; |
| 469 |
} |
| 470 |
} else { |
| 471 |
if (d1) { |
| 472 |
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */ |
| 473 |
z1 = d7 + d1; |
| 474 |
z4 = d5 + d1; |
| 475 |
z5 = MULTIPLY(d7 + z4, FIX_1_175875602); |
| 476 |
|
| 477 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 478 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 479 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 480 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 481 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 482 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 483 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 484 |
|
| 485 |
z3 += z5; |
| 486 |
z4 += z5; |
| 487 |
|
| 488 |
tmp0 += z1 + z3; |
| 489 |
tmp1 += z2 + z4; |
| 490 |
tmp2 = z2 + z3; |
| 491 |
tmp3 += z1 + z4; |
| 492 |
} else { |
| 493 |
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */ |
| 494 |
tmp0 = MULTIPLY(-d7, FIX_0_601344887); |
| 495 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 496 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 497 |
tmp1 = MULTIPLY(-d5, FIX_0_509795579); |
| 498 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 499 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 500 |
z5 = MULTIPLY(d5 + d7, FIX_1_175875602); |
| 501 |
|
| 502 |
z3 += z5; |
| 503 |
z4 += z5; |
| 504 |
|
| 505 |
tmp0 += z3; |
| 506 |
tmp1 += z4; |
| 507 |
tmp2 = z2 + z3; |
| 508 |
tmp3 = z1 + z4; |
| 509 |
} |
| 510 |
} |
| 511 |
} else { |
| 512 |
if (d3) { |
| 513 |
if (d1) { |
| 514 |
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */ |
| 515 |
z1 = d7 + d1; |
| 516 |
z3 = d7 + d3; |
| 517 |
z5 = MULTIPLY(z3 + d1, FIX_1_175875602); |
| 518 |
|
| 519 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 520 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 521 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 522 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 523 |
z2 = MULTIPLY(-d3, FIX_2_562915447); |
| 524 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 525 |
z4 = MULTIPLY(-d1, FIX_0_390180644); |
| 526 |
|
| 527 |
z3 += z5; |
| 528 |
z4 += z5; |
| 529 |
|
| 530 |
tmp0 += z1 + z3; |
| 531 |
tmp1 = z2 + z4; |
| 532 |
tmp2 += z2 + z3; |
| 533 |
tmp3 += z1 + z4; |
| 534 |
} else { |
| 535 |
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */ |
| 536 |
z3 = d7 + d3; |
| 537 |
|
| 538 |
tmp0 = MULTIPLY(-d7, FIX_0_601344887); |
| 539 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 540 |
tmp2 = MULTIPLY(d3, FIX_0_509795579); |
| 541 |
z2 = MULTIPLY(-d3, FIX_2_562915447); |
| 542 |
z5 = MULTIPLY(z3, FIX_1_175875602); |
| 543 |
z3 = MULTIPLY(-z3, FIX_0_785694958); |
| 544 |
|
| 545 |
tmp0 += z3; |
| 546 |
tmp1 = z2 + z5; |
| 547 |
tmp2 += z3; |
| 548 |
tmp3 = z1 + z5; |
| 549 |
} |
| 550 |
} else { |
| 551 |
if (d1) { |
| 552 |
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */ |
| 553 |
z1 = d7 + d1; |
| 554 |
z5 = MULTIPLY(z1, FIX_1_175875602); |
| 555 |
|
| 556 |
z1 = MULTIPLY(z1, FIX_0_275899380); |
| 557 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 558 |
tmp0 = MULTIPLY(-d7, FIX_1_662939225); |
| 559 |
z4 = MULTIPLY(-d1, FIX_0_390180644); |
| 560 |
tmp3 = MULTIPLY(d1, FIX_1_111140466); |
| 561 |
|
| 562 |
tmp0 += z1; |
| 563 |
tmp1 = z4 + z5; |
| 564 |
tmp2 = z3 + z5; |
| 565 |
tmp3 += z1; |
| 566 |
} else { |
| 567 |
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */ |
| 568 |
tmp0 = MULTIPLY(-d7, FIX_1_387039845); |
| 569 |
tmp1 = MULTIPLY(d7, FIX_1_175875602); |
| 570 |
tmp2 = MULTIPLY(-d7, FIX_0_785694958); |
| 571 |
tmp3 = MULTIPLY(d7, FIX_0_275899380); |
| 572 |
} |
| 573 |
} |
| 574 |
} |
| 575 |
} else { |
| 576 |
if (d5) { |
| 577 |
if (d3) { |
| 578 |
if (d1) { |
| 579 |
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */ |
| 580 |
z2 = d5 + d3; |
| 581 |
z4 = d5 + d1; |
| 582 |
z5 = MULTIPLY(d3 + z4, FIX_1_175875602); |
| 583 |
|
| 584 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 585 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 586 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 587 |
z1 = MULTIPLY(-d1, FIX_0_899976223); |
| 588 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 589 |
z3 = MULTIPLY(-d3, FIX_1_961570560); |
| 590 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 591 |
|
| 592 |
z3 += z5; |
| 593 |
z4 += z5; |
| 594 |
|
| 595 |
tmp0 = z1 + z3; |
| 596 |
tmp1 += z2 + z4; |
| 597 |
tmp2 += z2 + z3; |
| 598 |
tmp3 += z1 + z4; |
| 599 |
} else { |
| 600 |
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */ |
| 601 |
z2 = d5 + d3; |
| 602 |
|
| 603 |
z5 = MULTIPLY(z2, FIX_1_175875602); |
| 604 |
tmp1 = MULTIPLY(d5, FIX_1_662939225); |
| 605 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 606 |
z2 = MULTIPLY(-z2, FIX_1_387039845); |
| 607 |
tmp2 = MULTIPLY(d3, FIX_1_111140466); |
| 608 |
z3 = MULTIPLY(-d3, FIX_1_961570560); |
| 609 |
|
| 610 |
tmp0 = z3 + z5; |
| 611 |
tmp1 += z2; |
| 612 |
tmp2 += z2; |
| 613 |
tmp3 = z4 + z5; |
| 614 |
} |
| 615 |
} else { |
| 616 |
if (d1) { |
| 617 |
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */ |
| 618 |
z4 = d5 + d1; |
| 619 |
|
| 620 |
z5 = MULTIPLY(z4, FIX_1_175875602); |
| 621 |
z1 = MULTIPLY(-d1, FIX_0_899976223); |
| 622 |
tmp3 = MULTIPLY(d1, FIX_0_601344887); |
| 623 |
tmp1 = MULTIPLY(-d5, FIX_0_509795579); |
| 624 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 625 |
z4 = MULTIPLY(z4, FIX_0_785694958); |
| 626 |
|
| 627 |
tmp0 = z1 + z5; |
| 628 |
tmp1 += z4; |
| 629 |
tmp2 = z2 + z5; |
| 630 |
tmp3 += z4; |
| 631 |
} else { |
| 632 |
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */ |
| 633 |
tmp0 = MULTIPLY(d5, FIX_1_175875602); |
| 634 |
tmp1 = MULTIPLY(d5, FIX_0_275899380); |
| 635 |
tmp2 = MULTIPLY(-d5, FIX_1_387039845); |
| 636 |
tmp3 = MULTIPLY(d5, FIX_0_785694958); |
| 637 |
} |
| 638 |
} |
| 639 |
} else { |
| 640 |
if (d3) { |
| 641 |
if (d1) { |
| 642 |
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */ |
| 643 |
z5 = d1 + d3; |
| 644 |
tmp3 = MULTIPLY(d1, FIX_0_211164243); |
| 645 |
tmp2 = MULTIPLY(-d3, FIX_1_451774981); |
| 646 |
z1 = MULTIPLY(d1, FIX_1_061594337); |
| 647 |
z2 = MULTIPLY(-d3, FIX_2_172734803); |
| 648 |
z4 = MULTIPLY(z5, FIX_0_785694958); |
| 649 |
z5 = MULTIPLY(z5, FIX_1_175875602); |
| 650 |
|
| 651 |
tmp0 = z1 - z4; |
| 652 |
tmp1 = z2 + z4; |
| 653 |
tmp2 += z5; |
| 654 |
tmp3 += z5; |
| 655 |
} else { |
| 656 |
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */ |
| 657 |
tmp0 = MULTIPLY(-d3, FIX_0_785694958); |
| 658 |
tmp1 = MULTIPLY(-d3, FIX_1_387039845); |
| 659 |
tmp2 = MULTIPLY(-d3, FIX_0_275899380); |
| 660 |
tmp3 = MULTIPLY(d3, FIX_1_175875602); |
| 661 |
} |
| 662 |
} else { |
| 663 |
if (d1) { |
| 664 |
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */ |
| 665 |
tmp0 = MULTIPLY(d1, FIX_0_275899380); |
| 666 |
tmp1 = MULTIPLY(d1, FIX_0_785694958); |
| 667 |
tmp2 = MULTIPLY(d1, FIX_1_175875602); |
| 668 |
tmp3 = MULTIPLY(d1, FIX_1_387039845); |
| 669 |
} else { |
| 670 |
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */ |
| 671 |
tmp0 = tmp1 = tmp2 = tmp3 = 0; |
| 672 |
} |
| 673 |
} |
| 674 |
} |
| 675 |
} |
| 676 |
} |
| 677 |
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ |
| 678 |
|
| 679 |
dataptr[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS); |
| 680 |
dataptr[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS); |
| 681 |
dataptr[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS); |
| 682 |
dataptr[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS); |
| 683 |
dataptr[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS); |
| 684 |
dataptr[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS); |
| 685 |
dataptr[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS); |
| 686 |
dataptr[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS); |
| 687 |
|
| 688 |
dataptr += DCTSIZE; /* advance pointer to next row */ |
| 689 |
} |
| 690 |
|
| 691 |
/* Pass 2: process columns. */ |
| 692 |
/* Note that we must descale the results by a factor of 8 == 2**3, */ |
| 693 |
/* and also undo the PASS1_BITS scaling. */ |
| 694 |
|
| 695 |
dataptr = data; |
| 696 |
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { |
| 697 |
/* Columns of zeroes can be exploited in the same way as we did with rows. |
| 698 |
* However, the row calculation has created many nonzero AC terms, so the |
| 699 |
* simplification applies less often (typically 5% to 10% of the time). |
| 700 |
* On machines with very fast multiplication, it's possible that the |
| 701 |
* test takes more time than it's worth. In that case this section |
| 702 |
* may be commented out. |
| 703 |
*/ |
| 704 |
|
| 705 |
d0 = dataptr[DCTSIZE*0]; |
| 706 |
d1 = dataptr[DCTSIZE*1]; |
| 707 |
d2 = dataptr[DCTSIZE*2]; |
| 708 |
d3 = dataptr[DCTSIZE*3]; |
| 709 |
d4 = dataptr[DCTSIZE*4]; |
| 710 |
d5 = dataptr[DCTSIZE*5]; |
| 711 |
d6 = dataptr[DCTSIZE*6]; |
| 712 |
d7 = dataptr[DCTSIZE*7]; |
| 713 |
|
| 714 |
/* Even part: reverse the even part of the forward DCT. */ |
| 715 |
/* The rotator is sqrt(2)*c(-6). */ |
| 716 |
if (d6) { |
| 717 |
if (d4) { |
| 718 |
if (d2) { |
| 719 |
if (d0) { |
| 720 |
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ |
| 721 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 722 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 723 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 724 |
|
| 725 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 726 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 727 |
|
| 728 |
tmp10 = tmp0 + tmp3; |
| 729 |
tmp13 = tmp0 - tmp3; |
| 730 |
tmp11 = tmp1 + tmp2; |
| 731 |
tmp12 = tmp1 - tmp2; |
| 732 |
} else { |
| 733 |
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */ |
| 734 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 735 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 736 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 737 |
|
| 738 |
tmp0 = d4 << CONST_BITS; |
| 739 |
|
| 740 |
tmp10 = tmp0 + tmp3; |
| 741 |
tmp13 = tmp0 - tmp3; |
| 742 |
tmp11 = tmp2 - tmp0; |
| 743 |
tmp12 = -(tmp0 + tmp2); |
| 744 |
} |
| 745 |
} else { |
| 746 |
if (d0) { |
| 747 |
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ |
| 748 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 749 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 750 |
|
| 751 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 752 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 753 |
|
| 754 |
tmp10 = tmp0 + tmp3; |
| 755 |
tmp13 = tmp0 - tmp3; |
| 756 |
tmp11 = tmp1 + tmp2; |
| 757 |
tmp12 = tmp1 - tmp2; |
| 758 |
} else { |
| 759 |
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */ |
| 760 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 761 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 762 |
|
| 763 |
tmp0 = d4 << CONST_BITS; |
| 764 |
|
| 765 |
tmp10 = tmp0 + tmp3; |
| 766 |
tmp13 = tmp0 - tmp3; |
| 767 |
tmp11 = tmp2 - tmp0; |
| 768 |
tmp12 = -(tmp0 + tmp2); |
| 769 |
} |
| 770 |
} |
| 771 |
} else { |
| 772 |
if (d2) { |
| 773 |
if (d0) { |
| 774 |
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */ |
| 775 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 776 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 777 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 778 |
|
| 779 |
tmp0 = d0 << CONST_BITS; |
| 780 |
|
| 781 |
tmp10 = tmp0 + tmp3; |
| 782 |
tmp13 = tmp0 - tmp3; |
| 783 |
tmp11 = tmp0 + tmp2; |
| 784 |
tmp12 = tmp0 - tmp2; |
| 785 |
} else { |
| 786 |
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */ |
| 787 |
z1 = MULTIPLY(d2 + d6, FIX_0_541196100); |
| 788 |
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); |
| 789 |
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); |
| 790 |
|
| 791 |
tmp10 = tmp3; |
| 792 |
tmp13 = -tmp3; |
| 793 |
tmp11 = tmp2; |
| 794 |
tmp12 = -tmp2; |
| 795 |
} |
| 796 |
} else { |
| 797 |
if (d0) { |
| 798 |
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */ |
| 799 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 800 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 801 |
|
| 802 |
tmp0 = d0 << CONST_BITS; |
| 803 |
|
| 804 |
tmp10 = tmp0 + tmp3; |
| 805 |
tmp13 = tmp0 - tmp3; |
| 806 |
tmp11 = tmp0 + tmp2; |
| 807 |
tmp12 = tmp0 - tmp2; |
| 808 |
} else { |
| 809 |
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */ |
| 810 |
tmp2 = MULTIPLY(-d6, FIX_1_306562965); |
| 811 |
tmp3 = MULTIPLY(d6, FIX_0_541196100); |
| 812 |
|
| 813 |
tmp10 = tmp3; |
| 814 |
tmp13 = -tmp3; |
| 815 |
tmp11 = tmp2; |
| 816 |
tmp12 = -tmp2; |
| 817 |
} |
| 818 |
} |
| 819 |
} |
| 820 |
} else { |
| 821 |
if (d4) { |
| 822 |
if (d2) { |
| 823 |
if (d0) { |
| 824 |
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ |
| 825 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 826 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 827 |
|
| 828 |
tmp0 = (d0 + d4) << CONST_BITS; |
| 829 |
tmp1 = (d0 - d4) << CONST_BITS; |
| 830 |
|
| 831 |
tmp10 = tmp0 + tmp3; |
| 832 |
tmp13 = tmp0 - tmp3; |
| 833 |
tmp11 = tmp1 + tmp2; |
| 834 |
tmp12 = tmp1 - tmp2; |
| 835 |
} else { |
| 836 |
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */ |
| 837 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 838 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 839 |
|
| 840 |
tmp0 = d4 << CONST_BITS; |
| 841 |
|
| 842 |
tmp10 = tmp0 + tmp3; |
| 843 |
tmp13 = tmp0 - tmp3; |
| 844 |
tmp11 = tmp2 - tmp0; |
| 845 |
tmp12 = -(tmp0 + tmp2); |
| 846 |
} |
| 847 |
} else { |
| 848 |
if (d0) { |
| 849 |
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ |
| 850 |
tmp10 = tmp13 = (d0 + d4) << CONST_BITS; |
| 851 |
tmp11 = tmp12 = (d0 - d4) << CONST_BITS; |
| 852 |
} else { |
| 853 |
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */ |
| 854 |
tmp10 = tmp13 = d4 << CONST_BITS; |
| 855 |
tmp11 = tmp12 = -tmp10; |
| 856 |
} |
| 857 |
} |
| 858 |
} else { |
| 859 |
if (d2) { |
| 860 |
if (d0) { |
| 861 |
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */ |
| 862 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 863 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 864 |
|
| 865 |
tmp0 = d0 << CONST_BITS; |
| 866 |
|
| 867 |
tmp10 = tmp0 + tmp3; |
| 868 |
tmp13 = tmp0 - tmp3; |
| 869 |
tmp11 = tmp0 + tmp2; |
| 870 |
tmp12 = tmp0 - tmp2; |
| 871 |
} else { |
| 872 |
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */ |
| 873 |
tmp2 = MULTIPLY(d2, FIX_0_541196100); |
| 874 |
tmp3 = MULTIPLY(d2, FIX_1_306562965); |
| 875 |
|
| 876 |
tmp10 = tmp3; |
| 877 |
tmp13 = -tmp3; |
| 878 |
tmp11 = tmp2; |
| 879 |
tmp12 = -tmp2; |
| 880 |
} |
| 881 |
} else { |
| 882 |
if (d0) { |
| 883 |
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */ |
| 884 |
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS; |
| 885 |
} else { |
| 886 |
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */ |
| 887 |
tmp10 = tmp13 = tmp11 = tmp12 = 0; |
| 888 |
} |
| 889 |
} |
| 890 |
} |
| 891 |
} |
| 892 |
|
| 893 |
/* Odd part per figure 8; the matrix is unitary and hence its |
| 894 |
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. |
| 895 |
*/ |
| 896 |
if (d7) { |
| 897 |
if (d5) { |
| 898 |
if (d3) { |
| 899 |
if (d1) { |
| 900 |
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */ |
| 901 |
z1 = d7 + d1; |
| 902 |
z2 = d5 + d3; |
| 903 |
z3 = d7 + d3; |
| 904 |
z4 = d5 + d1; |
| 905 |
z5 = MULTIPLY(z3 + z4, FIX_1_175875602); |
| 906 |
|
| 907 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 908 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 909 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 910 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 911 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 912 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 913 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 914 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 915 |
|
| 916 |
z3 += z5; |
| 917 |
z4 += z5; |
| 918 |
|
| 919 |
tmp0 += z1 + z3; |
| 920 |
tmp1 += z2 + z4; |
| 921 |
tmp2 += z2 + z3; |
| 922 |
tmp3 += z1 + z4; |
| 923 |
} else { |
| 924 |
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */ |
| 925 |
z1 = d7; |
| 926 |
z2 = d5 + d3; |
| 927 |
z3 = d7 + d3; |
| 928 |
z5 = MULTIPLY(z3 + d5, FIX_1_175875602); |
| 929 |
|
| 930 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 931 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 932 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 933 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 934 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 935 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 936 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 937 |
|
| 938 |
z3 += z5; |
| 939 |
z4 += z5; |
| 940 |
|
| 941 |
tmp0 += z1 + z3; |
| 942 |
tmp1 += z2 + z4; |
| 943 |
tmp2 += z2 + z3; |
| 944 |
tmp3 = z1 + z4; |
| 945 |
} |
| 946 |
} else { |
| 947 |
if (d1) { |
| 948 |
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */ |
| 949 |
z1 = d7 + d1; |
| 950 |
z2 = d5; |
| 951 |
z3 = d7; |
| 952 |
z4 = d5 + d1; |
| 953 |
z5 = MULTIPLY(z3 + z4, FIX_1_175875602); |
| 954 |
|
| 955 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 956 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 957 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 958 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 959 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 960 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 961 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 962 |
|
| 963 |
z3 += z5; |
| 964 |
z4 += z5; |
| 965 |
|
| 966 |
tmp0 += z1 + z3; |
| 967 |
tmp1 += z2 + z4; |
| 968 |
tmp2 = z2 + z3; |
| 969 |
tmp3 += z1 + z4; |
| 970 |
} else { |
| 971 |
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */ |
| 972 |
tmp0 = MULTIPLY(-d7, FIX_0_601344887); |
| 973 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 974 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 975 |
tmp1 = MULTIPLY(-d5, FIX_0_509795579); |
| 976 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 977 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 978 |
z5 = MULTIPLY(d5 + d7, FIX_1_175875602); |
| 979 |
|
| 980 |
z3 += z5; |
| 981 |
z4 += z5; |
| 982 |
|
| 983 |
tmp0 += z3; |
| 984 |
tmp1 += z4; |
| 985 |
tmp2 = z2 + z3; |
| 986 |
tmp3 = z1 + z4; |
| 987 |
} |
| 988 |
} |
| 989 |
} else { |
| 990 |
if (d3) { |
| 991 |
if (d1) { |
| 992 |
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */ |
| 993 |
z1 = d7 + d1; |
| 994 |
z3 = d7 + d3; |
| 995 |
z5 = MULTIPLY(z3 + d1, FIX_1_175875602); |
| 996 |
|
| 997 |
tmp0 = MULTIPLY(d7, FIX_0_298631336); |
| 998 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 999 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 1000 |
z1 = MULTIPLY(-z1, FIX_0_899976223); |
| 1001 |
z2 = MULTIPLY(-d3, FIX_2_562915447); |
| 1002 |
z3 = MULTIPLY(-z3, FIX_1_961570560); |
| 1003 |
z4 = MULTIPLY(-d1, FIX_0_390180644); |
| 1004 |
|
| 1005 |
z3 += z5; |
| 1006 |
z4 += z5; |
| 1007 |
|
| 1008 |
tmp0 += z1 + z3; |
| 1009 |
tmp1 = z2 + z4; |
| 1010 |
tmp2 += z2 + z3; |
| 1011 |
tmp3 += z1 + z4; |
| 1012 |
} else { |
| 1013 |
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */ |
| 1014 |
z3 = d7 + d3; |
| 1015 |
|
| 1016 |
tmp0 = MULTIPLY(-d7, FIX_0_601344887); |
| 1017 |
z1 = MULTIPLY(-d7, FIX_0_899976223); |
| 1018 |
tmp2 = MULTIPLY(d3, FIX_0_509795579); |
| 1019 |
z2 = MULTIPLY(-d3, FIX_2_562915447); |
| 1020 |
z5 = MULTIPLY(z3, FIX_1_175875602); |
| 1021 |
z3 = MULTIPLY(-z3, FIX_0_785694958); |
| 1022 |
|
| 1023 |
tmp0 += z3; |
| 1024 |
tmp1 = z2 + z5; |
| 1025 |
tmp2 += z3; |
| 1026 |
tmp3 = z1 + z5; |
| 1027 |
} |
| 1028 |
} else { |
| 1029 |
if (d1) { |
| 1030 |
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */ |
| 1031 |
z1 = d7 + d1; |
| 1032 |
z5 = MULTIPLY(z1, FIX_1_175875602); |
| 1033 |
|
| 1034 |
z1 = MULTIPLY(z1, FIX_0_275899380); |
| 1035 |
z3 = MULTIPLY(-d7, FIX_1_961570560); |
| 1036 |
tmp0 = MULTIPLY(-d7, FIX_1_662939225); |
| 1037 |
z4 = MULTIPLY(-d1, FIX_0_390180644); |
| 1038 |
tmp3 = MULTIPLY(d1, FIX_1_111140466); |
| 1039 |
|
| 1040 |
tmp0 += z1; |
| 1041 |
tmp1 = z4 + z5; |
| 1042 |
tmp2 = z3 + z5; |
| 1043 |
tmp3 += z1; |
| 1044 |
} else { |
| 1045 |
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */ |
| 1046 |
tmp0 = MULTIPLY(-d7, FIX_1_387039845); |
| 1047 |
tmp1 = MULTIPLY(d7, FIX_1_175875602); |
| 1048 |
tmp2 = MULTIPLY(-d7, FIX_0_785694958); |
| 1049 |
tmp3 = MULTIPLY(d7, FIX_0_275899380); |
| 1050 |
} |
| 1051 |
} |
| 1052 |
} |
| 1053 |
} else { |
| 1054 |
if (d5) { |
| 1055 |
if (d3) { |
| 1056 |
if (d1) { |
| 1057 |
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */ |
| 1058 |
z2 = d5 + d3; |
| 1059 |
z4 = d5 + d1; |
| 1060 |
z5 = MULTIPLY(d3 + z4, FIX_1_175875602); |
| 1061 |
|
| 1062 |
tmp1 = MULTIPLY(d5, FIX_2_053119869); |
| 1063 |
tmp2 = MULTIPLY(d3, FIX_3_072711026); |
| 1064 |
tmp3 = MULTIPLY(d1, FIX_1_501321110); |
| 1065 |
z1 = MULTIPLY(-d1, FIX_0_899976223); |
| 1066 |
z2 = MULTIPLY(-z2, FIX_2_562915447); |
| 1067 |
z3 = MULTIPLY(-d3, FIX_1_961570560); |
| 1068 |
z4 = MULTIPLY(-z4, FIX_0_390180644); |
| 1069 |
|
| 1070 |
z3 += z5; |
| 1071 |
z4 += z5; |
| 1072 |
|
| 1073 |
tmp0 = z1 + z3; |
| 1074 |
tmp1 += z2 + z4; |
| 1075 |
tmp2 += z2 + z3; |
| 1076 |
tmp3 += z1 + z4; |
| 1077 |
} else { |
| 1078 |
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */ |
| 1079 |
z2 = d5 + d3; |
| 1080 |
|
| 1081 |
z5 = MULTIPLY(z2, FIX_1_175875602); |
| 1082 |
tmp1 = MULTIPLY(d5, FIX_1_662939225); |
| 1083 |
z4 = MULTIPLY(-d5, FIX_0_390180644); |
| 1084 |
z2 = MULTIPLY(-z2, FIX_1_387039845); |
| 1085 |
tmp2 = MULTIPLY(d3, FIX_1_111140466); |
| 1086 |
z3 = MULTIPLY(-d3, FIX_1_961570560); |
| 1087 |
|
| 1088 |
tmp0 = z3 + z5; |
| 1089 |
tmp1 += z2; |
| 1090 |
tmp2 += z2; |
| 1091 |
tmp3 = z4 + z5; |
| 1092 |
} |
| 1093 |
} else { |
| 1094 |
if (d1) { |
| 1095 |
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */ |
| 1096 |
z4 = d5 + d1; |
| 1097 |
|
| 1098 |
z5 = MULTIPLY(z4, FIX_1_175875602); |
| 1099 |
z1 = MULTIPLY(-d1, FIX_0_899976223); |
| 1100 |
tmp3 = MULTIPLY(d1, FIX_0_601344887); |
| 1101 |
tmp1 = MULTIPLY(-d5, FIX_0_509795579); |
| 1102 |
z2 = MULTIPLY(-d5, FIX_2_562915447); |
| 1103 |
z4 = MULTIPLY(z4, FIX_0_785694958); |
| 1104 |
|
| 1105 |
tmp0 = z1 + z5; |
| 1106 |
tmp1 += z4; |
| 1107 |
tmp2 = z2 + z5; |
| 1108 |
tmp3 += z4; |
| 1109 |
} else { |
| 1110 |
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */ |
| 1111 |
tmp0 = MULTIPLY(d5, FIX_1_175875602); |
| 1112 |
tmp1 = MULTIPLY(d5, FIX_0_275899380); |
| 1113 |
tmp2 = MULTIPLY(-d5, FIX_1_387039845); |
| 1114 |
tmp3 = MULTIPLY(d5, FIX_0_785694958); |
| 1115 |
} |
| 1116 |
} |
| 1117 |
} else { |
| 1118 |
if (d3) { |
| 1119 |
if (d1) { |
| 1120 |
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */ |
| 1121 |
z5 = d1 + d3; |
| 1122 |
tmp3 = MULTIPLY(d1, FIX_0_211164243); |
| 1123 |
tmp2 = MULTIPLY(-d3, FIX_1_451774981); |
| 1124 |
z1 = MULTIPLY(d1, FIX_1_061594337); |
| 1125 |
z2 = MULTIPLY(-d3, FIX_2_172734803); |
| 1126 |
z4 = MULTIPLY(z5, FIX_0_785694958); |
| 1127 |
z5 = MULTIPLY(z5, FIX_1_175875602); |
| 1128 |
|
| 1129 |
tmp0 = z1 - z4; |
| 1130 |
tmp1 = z2 + z4; |
| 1131 |
tmp2 += z5; |
| 1132 |
tmp3 += z5; |
| 1133 |
} else { |
| 1134 |
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */ |
| 1135 |
tmp0 = MULTIPLY(-d3, FIX_0_785694958); |
| 1136 |
tmp1 = MULTIPLY(-d3, FIX_1_387039845); |
| 1137 |
tmp2 = MULTIPLY(-d3, FIX_0_275899380); |
| 1138 |
tmp3 = MULTIPLY(d3, FIX_1_175875602); |
| 1139 |
} |
| 1140 |
} else { |
| 1141 |
if (d1) { |
| 1142 |
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */ |
| 1143 |
tmp0 = MULTIPLY(d1, FIX_0_275899380); |
| 1144 |
tmp1 = MULTIPLY(d1, FIX_0_785694958); |
| 1145 |
tmp2 = MULTIPLY(d1, FIX_1_175875602); |
| 1146 |
tmp3 = MULTIPLY(d1, FIX_1_387039845); |
| 1147 |
} else { |
| 1148 |
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */ |
| 1149 |
tmp0 = tmp1 = tmp2 = tmp3 = 0; |
| 1150 |
} |
| 1151 |
} |
| 1152 |
} |
| 1153 |
} |
| 1154 |
|
| 1155 |
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ |
| 1156 |
|
| 1157 |
dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3, |
| 1158 |
CONST_BITS+PASS1_BITS+3); |
| 1159 |
dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3, |
| 1160 |
CONST_BITS+PASS1_BITS+3); |
| 1161 |
dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2, |
| 1162 |
CONST_BITS+PASS1_BITS+3); |
| 1163 |
dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2, |
| 1164 |
CONST_BITS+PASS1_BITS+3); |
| 1165 |
dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1, |
| 1166 |
CONST_BITS+PASS1_BITS+3); |
| 1167 |
dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1, |
| 1168 |
CONST_BITS+PASS1_BITS+3); |
| 1169 |
dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0, |
| 1170 |
CONST_BITS+PASS1_BITS+3); |
| 1171 |
dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0, |
| 1172 |
CONST_BITS+PASS1_BITS+3); |
| 1173 |
|
| 1174 |
dataptr++; /* advance pointer to next column */ |
| 1175 |
} |
| 1176 |
} |
| 1177 |
|
| 1178 |
|
| 1179 |
/* here is the reference one, in case of problems with the normal one */ |
| 1180 |
|
| 1181 |
/* idctref.c, Inverse Discrete Fourier Transform, double precision */ |
| 1182 |
|
| 1183 |
/* Copyright (C) 1994, MPEG Software Simulation Group. All Rights Reserved. */ |
| 1184 |
|
| 1185 |
/* |
| 1186 |
* Disclaimer of Warranty |
| 1187 |
* |
| 1188 |
* These software programs are available to the user without any license fee or |
| 1189 |
* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims |
| 1190 |
* any and all warranties, whether express, implied, or statuary, including any |
| 1191 |
* implied warranties or merchantability or of fitness for a particular |
| 1192 |
* purpose. In no event shall the copyright-holder be liable for any |
| 1193 |
* incidental, punitive, or consequential damages of any kind whatsoever |
| 1194 |
* arising from the use of these programs. |
| 1195 |
* |
| 1196 |
* This disclaimer of warranty extends to the user of these programs and user's |
| 1197 |
* customers, employees, agents, transferees, successors, and assigns. |
| 1198 |
* |
| 1199 |
* The MPEG Software Simulation Group does not represent or warrant that the |
| 1200 |
* programs furnished hereunder are free of infringement of any third-party |
| 1201 |
* patents. |
| 1202 |
* |
| 1203 |
* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, |
| 1204 |
* are subject to royalty fees to patent holders. Many of these patents are |
| 1205 |
* general enough such that they are unavoidable regardless of implementation |
| 1206 |
* design. |
| 1207 |
* |
| 1208 |
*/ |
| 1209 |
|
| 1210 |
/* Perform IEEE 1180 reference (64-bit floating point, separable 8x1 |
| 1211 |
* direct matrix multiply) Inverse Discrete Cosine Transform |
| 1212 |
*/ |
| 1213 |
|
| 1214 |
|
| 1215 |
/* Here we use math.h to generate constants. Compiler results may |
| 1216 |
vary a little */ |
| 1217 |
|
| 1218 |
#ifndef PI |
| 1219 |
#ifdef M_PI |
| 1220 |
#define PI M_PI |
| 1221 |
#else |
| 1222 |
#define PI 3.14159265358979323846 |
| 1223 |
#endif |
| 1224 |
#endif |
| 1225 |
|
| 1226 |
/* cosine transform matrix for 8x1 IDCT */ |
| 1227 |
static double itrans_coef[8][8]; |
| 1228 |
|
| 1229 |
/* initialize DCT coefficient matrix */ |
| 1230 |
|
| 1231 |
void init_idctref() |
| 1232 |
{ |
| 1233 |
int freq, time; |
| 1234 |
double scale; |
| 1235 |
|
| 1236 |
for (freq=0; freq < 8; freq++) |
| 1237 |
{ |
| 1238 |
scale = (freq == 0) ? sqrt(0.125) : 0.5; |
| 1239 |
for (time=0; time<8; time++) |
| 1240 |
itrans_coef[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5)); |
| 1241 |
} |
| 1242 |
} |
| 1243 |
|
| 1244 |
/* perform IDCT matrix multiply for 8x8 coefficient block */ |
| 1245 |
|
| 1246 |
void reference_rev_dct(block) |
| 1247 |
int16 *block; |
| 1248 |
{ |
| 1249 |
int i, j, k, v; |
| 1250 |
double partial_product; |
| 1251 |
double tmp[64]; |
| 1252 |
|
| 1253 |
for (i=0; i<8; i++) |
| 1254 |
for (j=0; j<8; j++) |
| 1255 |
{ |
| 1256 |
partial_product = 0.0; |
| 1257 |
|
| 1258 |
for (k=0; k<8; k++) |
| 1259 |
partial_product+= itrans_coef[k][j]*block[8*i+k]; |
| 1260 |
|
| 1261 |
tmp[8*i+j] = partial_product; |
| 1262 |
} |
| 1263 |
|
| 1264 |
/* Transpose operation is integrated into address mapping by switching |
| 1265 |
loop order of i and j */ |
| 1266 |
|
| 1267 |
for (j=0; j<8; j++) |
| 1268 |
for (i=0; i<8; i++) |
| 1269 |
{ |
| 1270 |
partial_product = 0.0; |
| 1271 |
|
| 1272 |
for (k=0; k<8; k++) |
| 1273 |
partial_product+= itrans_coef[k][i]*tmp[8*k+j]; |
| 1274 |
|
| 1275 |
v = floor(partial_product+0.5); |
| 1276 |
block[8*i+j] = (v<-256) ? -256 : ((v>255) ? 255 : v); |
| 1277 |
} |
| 1278 |
} |
