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1 | /* |
2 | * This file is part of the Independent JPEG Group's software. | |
3 | * | |
4 | * The authors make NO WARRANTY or representation, either express or implied, | |
5 | * with respect to this software, its quality, accuracy, merchantability, or | |
6 | * fitness for a particular purpose. This software is provided "AS IS", and | |
7 | * you, its user, assume the entire risk as to its quality and accuracy. | |
8 | * | |
9 | * This software is copyright (C) 1991, 1992, Thomas G. Lane. | |
10 | * All Rights Reserved except as specified below. | |
11 | * | |
12 | * Permission is hereby granted to use, copy, modify, and distribute this | |
13 | * software (or portions thereof) for any purpose, without fee, subject to | |
14 | * these conditions: | |
15 | * (1) If any part of the source code for this software is distributed, then | |
16 | * this README file must be included, with this copyright and no-warranty | |
17 | * notice unaltered; and any additions, deletions, or changes to the original | |
18 | * files must be clearly indicated in accompanying documentation. | |
19 | * (2) If only executable code is distributed, then the accompanying | |
20 | * documentation must state that "this software is based in part on the work | |
21 | * of the Independent JPEG Group". | |
22 | * (3) Permission for use of this software is granted only if the user accepts | |
23 | * full responsibility for any undesirable consequences; the authors accept | |
24 | * NO LIABILITY for damages of any kind. | |
25 | * | |
26 | * These conditions apply to any software derived from or based on the IJG | |
27 | * code, not just to the unmodified library. If you use our work, you ought | |
28 | * to acknowledge us. | |
29 | * | |
30 | * Permission is NOT granted for the use of any IJG author's name or company | |
31 | * name in advertising or publicity relating to this software or products | |
32 | * derived from it. This software may be referred to only as "the Independent | |
33 | * JPEG Group's software". | |
34 | * | |
35 | * We specifically permit and encourage the use of this software as the basis | |
36 | * of commercial products, provided that all warranty or liability claims are | |
37 | * assumed by the product vendor. | |
38 | * | |
39 | * This file contains the basic inverse-DCT transformation subroutine. | |
40 | * | |
41 | * This implementation is based on an algorithm described in | |
42 | * C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT | |
43 | * Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics, | |
44 | * Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991. | |
45 | * The primary algorithm described there uses 11 multiplies and 29 adds. | |
46 | * We use their alternate method with 12 multiplies and 32 adds. | |
47 | * The advantage of this method is that no data path contains more than one | |
48 | * multiplication; this allows a very simple and accurate implementation in | |
49 | * scaled fixed-point arithmetic, with a minimal number of shifts. | |
50 | * | |
51 | * I've made lots of modifications to attempt to take advantage of the | |
52 | * sparse nature of the DCT matrices we're getting. Although the logic | |
53 | * is cumbersome, it's straightforward and the resulting code is much | |
54 | * faster. | |
55 | * | |
56 | * A better way to do this would be to pass in the DCT block as a sparse | |
57 | * matrix, perhaps with the difference cases encoded. | |
58 | */ | |
59 | ||
60 | /** | |
61 | * @file | |
62 | * Independent JPEG Group's LLM idct. | |
63 | */ | |
64 | ||
65 | #include "libavutil/common.h" | |
66 | ||
67 | #include "dct.h" | |
68 | #include "idctdsp.h" | |
69 | ||
70 | #define EIGHT_BIT_SAMPLES | |
71 | ||
72 | #define DCTSIZE 8 | |
73 | #define DCTSIZE2 64 | |
74 | ||
75 | #define GLOBAL | |
76 | ||
77 | #define RIGHT_SHIFT(x, n) ((x) >> (n)) | |
78 | ||
79 | typedef int16_t DCTBLOCK[DCTSIZE2]; | |
80 | ||
81 | #define CONST_BITS 13 | |
82 | ||
83 | /* | |
84 | * This routine is specialized to the case DCTSIZE = 8. | |
85 | */ | |
86 | ||
87 | #if DCTSIZE != 8 | |
88 | Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ | |
89 | #endif | |
90 | ||
91 | ||
92 | /* | |
93 | * A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT | |
94 | * on each column. Direct algorithms are also available, but they are | |
95 | * much more complex and seem not to be any faster when reduced to code. | |
96 | * | |
97 | * The poop on this scaling stuff is as follows: | |
98 | * | |
99 | * Each 1-D IDCT step produces outputs which are a factor of sqrt(N) | |
100 | * larger than the true IDCT outputs. The final outputs are therefore | |
101 | * a factor of N larger than desired; since N=8 this can be cured by | |
102 | * a simple right shift at the end of the algorithm. The advantage of | |
103 | * this arrangement is that we save two multiplications per 1-D IDCT, | |
104 | * because the y0 and y4 inputs need not be divided by sqrt(N). | |
105 | * | |
106 | * We have to do addition and subtraction of the integer inputs, which | |
107 | * is no problem, and multiplication by fractional constants, which is | |
108 | * a problem to do in integer arithmetic. We multiply all the constants | |
109 | * by CONST_SCALE and convert them to integer constants (thus retaining | |
110 | * CONST_BITS bits of precision in the constants). After doing a | |
111 | * multiplication we have to divide the product by CONST_SCALE, with proper | |
112 | * rounding, to produce the correct output. This division can be done | |
113 | * cheaply as a right shift of CONST_BITS bits. We postpone shifting | |
114 | * as long as possible so that partial sums can be added together with | |
115 | * full fractional precision. | |
116 | * | |
117 | * The outputs of the first pass are scaled up by PASS1_BITS bits so that | |
118 | * they are represented to better-than-integral precision. These outputs | |
119 | * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word | |
120 | * with the recommended scaling. (To scale up 12-bit sample data further, an | |
121 | * intermediate int32 array would be needed.) | |
122 | * | |
123 | * To avoid overflow of the 32-bit intermediate results in pass 2, we must | |
124 | * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis | |
125 | * shows that the values given below are the most effective. | |
126 | */ | |
127 | ||
128 | #ifdef EIGHT_BIT_SAMPLES | |
129 | #define PASS1_BITS 2 | |
130 | #else | |
131 | #define PASS1_BITS 1 /* lose a little precision to avoid overflow */ | |
132 | #endif | |
133 | ||
134 | #define ONE ((int32_t) 1) | |
135 | ||
136 | #define CONST_SCALE (ONE << CONST_BITS) | |
137 | ||
138 | /* Convert a positive real constant to an integer scaled by CONST_SCALE. | |
139 | * IMPORTANT: if your compiler doesn't do this arithmetic at compile time, | |
140 | * you will pay a significant penalty in run time. In that case, figure | |
141 | * the correct integer constant values and insert them by hand. | |
142 | */ | |
143 | ||
144 | /* Actually FIX is no longer used, we precomputed them all */ | |
145 | #define FIX(x) ((int32_t) ((x) * CONST_SCALE + 0.5)) | |
146 | ||
147 | /* Descale and correctly round an int32_t value that's scaled by N bits. | |
148 | * We assume RIGHT_SHIFT rounds towards minus infinity, so adding | |
149 | * the fudge factor is correct for either sign of X. | |
150 | */ | |
151 | ||
152 | #define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) | |
153 | ||
154 | /* Multiply an int32_t variable by an int32_t constant to yield an int32_t result. | |
155 | * For 8-bit samples with the recommended scaling, all the variable | |
156 | * and constant values involved are no more than 16 bits wide, so a | |
157 | * 16x16->32 bit multiply can be used instead of a full 32x32 multiply; | |
158 | * this provides a useful speedup on many machines. | |
159 | * There is no way to specify a 16x16->32 multiply in portable C, but | |
160 | * some C compilers will do the right thing if you provide the correct | |
161 | * combination of casts. | |
162 | * NB: for 12-bit samples, a full 32-bit multiplication will be needed. | |
163 | */ | |
164 | ||
165 | #ifdef EIGHT_BIT_SAMPLES | |
166 | #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ | |
167 | #define MULTIPLY(var,const) (((int16_t) (var)) * ((int16_t) (const))) | |
168 | #endif | |
169 | #ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ | |
170 | #define MULTIPLY(var,const) (((int16_t) (var)) * ((int32_t) (const))) | |
171 | #endif | |
172 | #endif | |
173 | ||
174 | #ifndef MULTIPLY /* default definition */ | |
175 | #define MULTIPLY(var,const) ((var) * (const)) | |
176 | #endif | |
177 | ||
178 | ||
179 | /* | |
180 | Unlike our decoder where we approximate the FIXes, we need to use exact | |
181 | ones here or successive P-frames will drift too much with Reference frame coding | |
182 | */ | |
183 | #define FIX_0_211164243 1730 | |
184 | #define FIX_0_275899380 2260 | |
185 | #define FIX_0_298631336 2446 | |
186 | #define FIX_0_390180644 3196 | |
187 | #define FIX_0_509795579 4176 | |
188 | #define FIX_0_541196100 4433 | |
189 | #define FIX_0_601344887 4926 | |
190 | #define FIX_0_765366865 6270 | |
191 | #define FIX_0_785694958 6436 | |
192 | #define FIX_0_899976223 7373 | |
193 | #define FIX_1_061594337 8697 | |
194 | #define FIX_1_111140466 9102 | |
195 | #define FIX_1_175875602 9633 | |
196 | #define FIX_1_306562965 10703 | |
197 | #define FIX_1_387039845 11363 | |
198 | #define FIX_1_451774981 11893 | |
199 | #define FIX_1_501321110 12299 | |
200 | #define FIX_1_662939225 13623 | |
201 | #define FIX_1_847759065 15137 | |
202 | #define FIX_1_961570560 16069 | |
203 | #define FIX_2_053119869 16819 | |
204 | #define FIX_2_172734803 17799 | |
205 | #define FIX_2_562915447 20995 | |
206 | #define FIX_3_072711026 25172 | |
207 | ||
208 | /* | |
209 | * Perform the inverse DCT on one block of coefficients. | |
210 | */ | |
211 | ||
212 | void ff_j_rev_dct(DCTBLOCK data) | |
213 | { | |
214 | int32_t tmp0, tmp1, tmp2, tmp3; | |
215 | int32_t tmp10, tmp11, tmp12, tmp13; | |
216 | int32_t z1, z2, z3, z4, z5; | |
217 | int32_t d0, d1, d2, d3, d4, d5, d6, d7; | |
218 | register int16_t *dataptr; | |
219 | int rowctr; | |
220 | ||
221 | /* Pass 1: process rows. */ | |
222 | /* Note results are scaled up by sqrt(8) compared to a true IDCT; */ | |
223 | /* furthermore, we scale the results by 2**PASS1_BITS. */ | |
224 | ||
225 | dataptr = data; | |
226 | ||
227 | for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { | |
228 | /* Due to quantization, we will usually find that many of the input | |
229 | * coefficients are zero, especially the AC terms. We can exploit this | |
230 | * by short-circuiting the IDCT calculation for any row in which all | |
231 | * the AC terms are zero. In that case each output is equal to the | |
232 | * DC coefficient (with scale factor as needed). | |
233 | * With typical images and quantization tables, half or more of the | |
234 | * row DCT calculations can be simplified this way. | |
235 | */ | |
236 | ||
237 | register int *idataptr = (int*)dataptr; | |
238 | ||
239 | /* WARNING: we do the same permutation as MMX idct to simplify the | |
240 | video core */ | |
241 | d0 = dataptr[0]; | |
242 | d2 = dataptr[1]; | |
243 | d4 = dataptr[2]; | |
244 | d6 = dataptr[3]; | |
245 | d1 = dataptr[4]; | |
246 | d3 = dataptr[5]; | |
247 | d5 = dataptr[6]; | |
248 | d7 = dataptr[7]; | |
249 | ||
250 | if ((d1 | d2 | d3 | d4 | d5 | d6 | d7) == 0) { | |
251 | /* AC terms all zero */ | |
252 | if (d0) { | |
253 | /* Compute a 32 bit value to assign. */ | |
254 | int16_t dcval = (int16_t) (d0 * (1 << PASS1_BITS)); | |
255 | register int v = (dcval & 0xffff) | ((dcval * (1 << 16)) & 0xffff0000); | |
256 | ||
257 | idataptr[0] = v; | |
258 | idataptr[1] = v; | |
259 | idataptr[2] = v; | |
260 | idataptr[3] = v; | |
261 | } | |
262 | ||
263 | dataptr += DCTSIZE; /* advance pointer to next row */ | |
264 | continue; | |
265 | } | |
266 | ||
267 | /* Even part: reverse the even part of the forward DCT. */ | |
268 | /* The rotator is sqrt(2)*c(-6). */ | |
269 | { | |
270 | if (d6) { | |
271 | if (d2) { | |
272 | /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ | |
273 | z1 = MULTIPLY(d2 + d6, FIX_0_541196100); | |
274 | tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); | |
275 | tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); | |
276 | ||
277 | tmp0 = (d0 + d4) * CONST_SCALE; | |
278 | tmp1 = (d0 - d4) * CONST_SCALE; | |
279 | ||
280 | tmp10 = tmp0 + tmp3; | |
281 | tmp13 = tmp0 - tmp3; | |
282 | tmp11 = tmp1 + tmp2; | |
283 | tmp12 = tmp1 - tmp2; | |
284 | } else { | |
285 | /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ | |
286 | tmp2 = MULTIPLY(-d6, FIX_1_306562965); | |
287 | tmp3 = MULTIPLY(d6, FIX_0_541196100); | |
288 | ||
289 | tmp0 = (d0 + d4) * CONST_SCALE; | |
290 | tmp1 = (d0 - d4) * CONST_SCALE; | |
291 | ||
292 | tmp10 = tmp0 + tmp3; | |
293 | tmp13 = tmp0 - tmp3; | |
294 | tmp11 = tmp1 + tmp2; | |
295 | tmp12 = tmp1 - tmp2; | |
296 | } | |
297 | } else { | |
298 | if (d2) { | |
299 | /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ | |
300 | tmp2 = MULTIPLY(d2, FIX_0_541196100); | |
301 | tmp3 = MULTIPLY(d2, FIX_1_306562965); | |
302 | ||
303 | tmp0 = (d0 + d4) * CONST_SCALE; | |
304 | tmp1 = (d0 - d4) * CONST_SCALE; | |
305 | ||
306 | tmp10 = tmp0 + tmp3; | |
307 | tmp13 = tmp0 - tmp3; | |
308 | tmp11 = tmp1 + tmp2; | |
309 | tmp12 = tmp1 - tmp2; | |
310 | } else { | |
311 | /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ | |
312 | tmp10 = tmp13 = (d0 + d4) * CONST_SCALE; | |
313 | tmp11 = tmp12 = (d0 - d4) * CONST_SCALE; | |
314 | } | |
315 | } | |
316 | ||
317 | /* Odd part per figure 8; the matrix is unitary and hence its | |
318 | * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. | |
319 | */ | |
320 | ||
321 | if (d7) { | |
322 | if (d5) { | |
323 | if (d3) { | |
324 | if (d1) { | |
325 | /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */ | |
326 | z1 = d7 + d1; | |
327 | z2 = d5 + d3; | |
328 | z3 = d7 + d3; | |
329 | z4 = d5 + d1; | |
330 | z5 = MULTIPLY(z3 + z4, FIX_1_175875602); | |
331 | ||
332 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
333 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
334 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
335 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
336 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
337 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
338 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
339 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
340 | ||
341 | z3 += z5; | |
342 | z4 += z5; | |
343 | ||
344 | tmp0 += z1 + z3; | |
345 | tmp1 += z2 + z4; | |
346 | tmp2 += z2 + z3; | |
347 | tmp3 += z1 + z4; | |
348 | } else { | |
349 | /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */ | |
350 | z2 = d5 + d3; | |
351 | z3 = d7 + d3; | |
352 | z5 = MULTIPLY(z3 + d5, FIX_1_175875602); | |
353 | ||
354 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
355 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
356 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
357 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
358 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
359 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
360 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
361 | ||
362 | z3 += z5; | |
363 | z4 += z5; | |
364 | ||
365 | tmp0 += z1 + z3; | |
366 | tmp1 += z2 + z4; | |
367 | tmp2 += z2 + z3; | |
368 | tmp3 = z1 + z4; | |
369 | } | |
370 | } else { | |
371 | if (d1) { | |
372 | /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */ | |
373 | z1 = d7 + d1; | |
374 | z4 = d5 + d1; | |
375 | z5 = MULTIPLY(d7 + z4, FIX_1_175875602); | |
376 | ||
377 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
378 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
379 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
380 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
381 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
382 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
383 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
384 | ||
385 | z3 += z5; | |
386 | z4 += z5; | |
387 | ||
388 | tmp0 += z1 + z3; | |
389 | tmp1 += z2 + z4; | |
390 | tmp2 = z2 + z3; | |
391 | tmp3 += z1 + z4; | |
392 | } else { | |
393 | /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */ | |
394 | tmp0 = MULTIPLY(-d7, FIX_0_601344887); | |
395 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
396 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
397 | tmp1 = MULTIPLY(-d5, FIX_0_509795579); | |
398 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
399 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
400 | z5 = MULTIPLY(d5 + d7, FIX_1_175875602); | |
401 | ||
402 | z3 += z5; | |
403 | z4 += z5; | |
404 | ||
405 | tmp0 += z3; | |
406 | tmp1 += z4; | |
407 | tmp2 = z2 + z3; | |
408 | tmp3 = z1 + z4; | |
409 | } | |
410 | } | |
411 | } else { | |
412 | if (d3) { | |
413 | if (d1) { | |
414 | /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */ | |
415 | z1 = d7 + d1; | |
416 | z3 = d7 + d3; | |
417 | z5 = MULTIPLY(z3 + d1, FIX_1_175875602); | |
418 | ||
419 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
420 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
421 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
422 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
423 | z2 = MULTIPLY(-d3, FIX_2_562915447); | |
424 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
425 | z4 = MULTIPLY(-d1, FIX_0_390180644); | |
426 | ||
427 | z3 += z5; | |
428 | z4 += z5; | |
429 | ||
430 | tmp0 += z1 + z3; | |
431 | tmp1 = z2 + z4; | |
432 | tmp2 += z2 + z3; | |
433 | tmp3 += z1 + z4; | |
434 | } else { | |
435 | /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */ | |
436 | z3 = d7 + d3; | |
437 | ||
438 | tmp0 = MULTIPLY(-d7, FIX_0_601344887); | |
439 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
440 | tmp2 = MULTIPLY(d3, FIX_0_509795579); | |
441 | z2 = MULTIPLY(-d3, FIX_2_562915447); | |
442 | z5 = MULTIPLY(z3, FIX_1_175875602); | |
443 | z3 = MULTIPLY(-z3, FIX_0_785694958); | |
444 | ||
445 | tmp0 += z3; | |
446 | tmp1 = z2 + z5; | |
447 | tmp2 += z3; | |
448 | tmp3 = z1 + z5; | |
449 | } | |
450 | } else { | |
451 | if (d1) { | |
452 | /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */ | |
453 | z1 = d7 + d1; | |
454 | z5 = MULTIPLY(z1, FIX_1_175875602); | |
455 | ||
456 | z1 = MULTIPLY(z1, FIX_0_275899380); | |
457 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
458 | tmp0 = MULTIPLY(-d7, FIX_1_662939225); | |
459 | z4 = MULTIPLY(-d1, FIX_0_390180644); | |
460 | tmp3 = MULTIPLY(d1, FIX_1_111140466); | |
461 | ||
462 | tmp0 += z1; | |
463 | tmp1 = z4 + z5; | |
464 | tmp2 = z3 + z5; | |
465 | tmp3 += z1; | |
466 | } else { | |
467 | /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */ | |
468 | tmp0 = MULTIPLY(-d7, FIX_1_387039845); | |
469 | tmp1 = MULTIPLY(d7, FIX_1_175875602); | |
470 | tmp2 = MULTIPLY(-d7, FIX_0_785694958); | |
471 | tmp3 = MULTIPLY(d7, FIX_0_275899380); | |
472 | } | |
473 | } | |
474 | } | |
475 | } else { | |
476 | if (d5) { | |
477 | if (d3) { | |
478 | if (d1) { | |
479 | /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */ | |
480 | z2 = d5 + d3; | |
481 | z4 = d5 + d1; | |
482 | z5 = MULTIPLY(d3 + z4, FIX_1_175875602); | |
483 | ||
484 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
485 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
486 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
487 | z1 = MULTIPLY(-d1, FIX_0_899976223); | |
488 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
489 | z3 = MULTIPLY(-d3, FIX_1_961570560); | |
490 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
491 | ||
492 | z3 += z5; | |
493 | z4 += z5; | |
494 | ||
495 | tmp0 = z1 + z3; | |
496 | tmp1 += z2 + z4; | |
497 | tmp2 += z2 + z3; | |
498 | tmp3 += z1 + z4; | |
499 | } else { | |
500 | /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */ | |
501 | z2 = d5 + d3; | |
502 | ||
503 | z5 = MULTIPLY(z2, FIX_1_175875602); | |
504 | tmp1 = MULTIPLY(d5, FIX_1_662939225); | |
505 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
506 | z2 = MULTIPLY(-z2, FIX_1_387039845); | |
507 | tmp2 = MULTIPLY(d3, FIX_1_111140466); | |
508 | z3 = MULTIPLY(-d3, FIX_1_961570560); | |
509 | ||
510 | tmp0 = z3 + z5; | |
511 | tmp1 += z2; | |
512 | tmp2 += z2; | |
513 | tmp3 = z4 + z5; | |
514 | } | |
515 | } else { | |
516 | if (d1) { | |
517 | /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */ | |
518 | z4 = d5 + d1; | |
519 | ||
520 | z5 = MULTIPLY(z4, FIX_1_175875602); | |
521 | z1 = MULTIPLY(-d1, FIX_0_899976223); | |
522 | tmp3 = MULTIPLY(d1, FIX_0_601344887); | |
523 | tmp1 = MULTIPLY(-d5, FIX_0_509795579); | |
524 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
525 | z4 = MULTIPLY(z4, FIX_0_785694958); | |
526 | ||
527 | tmp0 = z1 + z5; | |
528 | tmp1 += z4; | |
529 | tmp2 = z2 + z5; | |
530 | tmp3 += z4; | |
531 | } else { | |
532 | /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */ | |
533 | tmp0 = MULTIPLY(d5, FIX_1_175875602); | |
534 | tmp1 = MULTIPLY(d5, FIX_0_275899380); | |
535 | tmp2 = MULTIPLY(-d5, FIX_1_387039845); | |
536 | tmp3 = MULTIPLY(d5, FIX_0_785694958); | |
537 | } | |
538 | } | |
539 | } else { | |
540 | if (d3) { | |
541 | if (d1) { | |
542 | /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */ | |
543 | z5 = d1 + d3; | |
544 | tmp3 = MULTIPLY(d1, FIX_0_211164243); | |
545 | tmp2 = MULTIPLY(-d3, FIX_1_451774981); | |
546 | z1 = MULTIPLY(d1, FIX_1_061594337); | |
547 | z2 = MULTIPLY(-d3, FIX_2_172734803); | |
548 | z4 = MULTIPLY(z5, FIX_0_785694958); | |
549 | z5 = MULTIPLY(z5, FIX_1_175875602); | |
550 | ||
551 | tmp0 = z1 - z4; | |
552 | tmp1 = z2 + z4; | |
553 | tmp2 += z5; | |
554 | tmp3 += z5; | |
555 | } else { | |
556 | /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */ | |
557 | tmp0 = MULTIPLY(-d3, FIX_0_785694958); | |
558 | tmp1 = MULTIPLY(-d3, FIX_1_387039845); | |
559 | tmp2 = MULTIPLY(-d3, FIX_0_275899380); | |
560 | tmp3 = MULTIPLY(d3, FIX_1_175875602); | |
561 | } | |
562 | } else { | |
563 | if (d1) { | |
564 | /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */ | |
565 | tmp0 = MULTIPLY(d1, FIX_0_275899380); | |
566 | tmp1 = MULTIPLY(d1, FIX_0_785694958); | |
567 | tmp2 = MULTIPLY(d1, FIX_1_175875602); | |
568 | tmp3 = MULTIPLY(d1, FIX_1_387039845); | |
569 | } else { | |
570 | /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */ | |
571 | tmp0 = tmp1 = tmp2 = tmp3 = 0; | |
572 | } | |
573 | } | |
574 | } | |
575 | } | |
576 | } | |
577 | /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ | |
578 | ||
579 | dataptr[0] = (int16_t) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS); | |
580 | dataptr[7] = (int16_t) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS); | |
581 | dataptr[1] = (int16_t) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS); | |
582 | dataptr[6] = (int16_t) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS); | |
583 | dataptr[2] = (int16_t) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS); | |
584 | dataptr[5] = (int16_t) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS); | |
585 | dataptr[3] = (int16_t) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS); | |
586 | dataptr[4] = (int16_t) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS); | |
587 | ||
588 | dataptr += DCTSIZE; /* advance pointer to next row */ | |
589 | } | |
590 | ||
591 | /* Pass 2: process columns. */ | |
592 | /* Note that we must descale the results by a factor of 8 == 2**3, */ | |
593 | /* and also undo the PASS1_BITS scaling. */ | |
594 | ||
595 | dataptr = data; | |
596 | for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { | |
597 | /* Columns of zeroes can be exploited in the same way as we did with rows. | |
598 | * However, the row calculation has created many nonzero AC terms, so the | |
599 | * simplification applies less often (typically 5% to 10% of the time). | |
600 | * On machines with very fast multiplication, it's possible that the | |
601 | * test takes more time than it's worth. In that case this section | |
602 | * may be commented out. | |
603 | */ | |
604 | ||
605 | d0 = dataptr[DCTSIZE*0]; | |
606 | d1 = dataptr[DCTSIZE*1]; | |
607 | d2 = dataptr[DCTSIZE*2]; | |
608 | d3 = dataptr[DCTSIZE*3]; | |
609 | d4 = dataptr[DCTSIZE*4]; | |
610 | d5 = dataptr[DCTSIZE*5]; | |
611 | d6 = dataptr[DCTSIZE*6]; | |
612 | d7 = dataptr[DCTSIZE*7]; | |
613 | ||
614 | /* Even part: reverse the even part of the forward DCT. */ | |
615 | /* The rotator is sqrt(2)*c(-6). */ | |
616 | if (d6) { | |
617 | if (d2) { | |
618 | /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ | |
619 | z1 = MULTIPLY(d2 + d6, FIX_0_541196100); | |
620 | tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); | |
621 | tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); | |
622 | ||
623 | tmp0 = (d0 + d4) * CONST_SCALE; | |
624 | tmp1 = (d0 - d4) * CONST_SCALE; | |
625 | ||
626 | tmp10 = tmp0 + tmp3; | |
627 | tmp13 = tmp0 - tmp3; | |
628 | tmp11 = tmp1 + tmp2; | |
629 | tmp12 = tmp1 - tmp2; | |
630 | } else { | |
631 | /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ | |
632 | tmp2 = MULTIPLY(-d6, FIX_1_306562965); | |
633 | tmp3 = MULTIPLY(d6, FIX_0_541196100); | |
634 | ||
635 | tmp0 = (d0 + d4) * CONST_SCALE; | |
636 | tmp1 = (d0 - d4) * CONST_SCALE; | |
637 | ||
638 | tmp10 = tmp0 + tmp3; | |
639 | tmp13 = tmp0 - tmp3; | |
640 | tmp11 = tmp1 + tmp2; | |
641 | tmp12 = tmp1 - tmp2; | |
642 | } | |
643 | } else { | |
644 | if (d2) { | |
645 | /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ | |
646 | tmp2 = MULTIPLY(d2, FIX_0_541196100); | |
647 | tmp3 = MULTIPLY(d2, FIX_1_306562965); | |
648 | ||
649 | tmp0 = (d0 + d4) * CONST_SCALE; | |
650 | tmp1 = (d0 - d4) * CONST_SCALE; | |
651 | ||
652 | tmp10 = tmp0 + tmp3; | |
653 | tmp13 = tmp0 - tmp3; | |
654 | tmp11 = tmp1 + tmp2; | |
655 | tmp12 = tmp1 - tmp2; | |
656 | } else { | |
657 | /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ | |
658 | tmp10 = tmp13 = (d0 + d4) * CONST_SCALE; | |
659 | tmp11 = tmp12 = (d0 - d4) * CONST_SCALE; | |
660 | } | |
661 | } | |
662 | ||
663 | /* Odd part per figure 8; the matrix is unitary and hence its | |
664 | * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. | |
665 | */ | |
666 | if (d7) { | |
667 | if (d5) { | |
668 | if (d3) { | |
669 | if (d1) { | |
670 | /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */ | |
671 | z1 = d7 + d1; | |
672 | z2 = d5 + d3; | |
673 | z3 = d7 + d3; | |
674 | z4 = d5 + d1; | |
675 | z5 = MULTIPLY(z3 + z4, FIX_1_175875602); | |
676 | ||
677 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
678 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
679 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
680 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
681 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
682 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
683 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
684 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
685 | ||
686 | z3 += z5; | |
687 | z4 += z5; | |
688 | ||
689 | tmp0 += z1 + z3; | |
690 | tmp1 += z2 + z4; | |
691 | tmp2 += z2 + z3; | |
692 | tmp3 += z1 + z4; | |
693 | } else { | |
694 | /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */ | |
695 | z2 = d5 + d3; | |
696 | z3 = d7 + d3; | |
697 | z5 = MULTIPLY(z3 + d5, FIX_1_175875602); | |
698 | ||
699 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
700 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
701 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
702 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
703 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
704 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
705 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
706 | ||
707 | z3 += z5; | |
708 | z4 += z5; | |
709 | ||
710 | tmp0 += z1 + z3; | |
711 | tmp1 += z2 + z4; | |
712 | tmp2 += z2 + z3; | |
713 | tmp3 = z1 + z4; | |
714 | } | |
715 | } else { | |
716 | if (d1) { | |
717 | /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */ | |
718 | z1 = d7 + d1; | |
719 | z3 = d7; | |
720 | z4 = d5 + d1; | |
721 | z5 = MULTIPLY(z3 + z4, FIX_1_175875602); | |
722 | ||
723 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
724 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
725 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
726 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
727 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
728 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
729 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
730 | ||
731 | z3 += z5; | |
732 | z4 += z5; | |
733 | ||
734 | tmp0 += z1 + z3; | |
735 | tmp1 += z2 + z4; | |
736 | tmp2 = z2 + z3; | |
737 | tmp3 += z1 + z4; | |
738 | } else { | |
739 | /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */ | |
740 | tmp0 = MULTIPLY(-d7, FIX_0_601344887); | |
741 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
742 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
743 | tmp1 = MULTIPLY(-d5, FIX_0_509795579); | |
744 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
745 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
746 | z5 = MULTIPLY(d5 + d7, FIX_1_175875602); | |
747 | ||
748 | z3 += z5; | |
749 | z4 += z5; | |
750 | ||
751 | tmp0 += z3; | |
752 | tmp1 += z4; | |
753 | tmp2 = z2 + z3; | |
754 | tmp3 = z1 + z4; | |
755 | } | |
756 | } | |
757 | } else { | |
758 | if (d3) { | |
759 | if (d1) { | |
760 | /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */ | |
761 | z1 = d7 + d1; | |
762 | z3 = d7 + d3; | |
763 | z5 = MULTIPLY(z3 + d1, FIX_1_175875602); | |
764 | ||
765 | tmp0 = MULTIPLY(d7, FIX_0_298631336); | |
766 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
767 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
768 | z1 = MULTIPLY(-z1, FIX_0_899976223); | |
769 | z2 = MULTIPLY(-d3, FIX_2_562915447); | |
770 | z3 = MULTIPLY(-z3, FIX_1_961570560); | |
771 | z4 = MULTIPLY(-d1, FIX_0_390180644); | |
772 | ||
773 | z3 += z5; | |
774 | z4 += z5; | |
775 | ||
776 | tmp0 += z1 + z3; | |
777 | tmp1 = z2 + z4; | |
778 | tmp2 += z2 + z3; | |
779 | tmp3 += z1 + z4; | |
780 | } else { | |
781 | /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */ | |
782 | z3 = d7 + d3; | |
783 | ||
784 | tmp0 = MULTIPLY(-d7, FIX_0_601344887); | |
785 | z1 = MULTIPLY(-d7, FIX_0_899976223); | |
786 | tmp2 = MULTIPLY(d3, FIX_0_509795579); | |
787 | z2 = MULTIPLY(-d3, FIX_2_562915447); | |
788 | z5 = MULTIPLY(z3, FIX_1_175875602); | |
789 | z3 = MULTIPLY(-z3, FIX_0_785694958); | |
790 | ||
791 | tmp0 += z3; | |
792 | tmp1 = z2 + z5; | |
793 | tmp2 += z3; | |
794 | tmp3 = z1 + z5; | |
795 | } | |
796 | } else { | |
797 | if (d1) { | |
798 | /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */ | |
799 | z1 = d7 + d1; | |
800 | z5 = MULTIPLY(z1, FIX_1_175875602); | |
801 | ||
802 | z1 = MULTIPLY(z1, FIX_0_275899380); | |
803 | z3 = MULTIPLY(-d7, FIX_1_961570560); | |
804 | tmp0 = MULTIPLY(-d7, FIX_1_662939225); | |
805 | z4 = MULTIPLY(-d1, FIX_0_390180644); | |
806 | tmp3 = MULTIPLY(d1, FIX_1_111140466); | |
807 | ||
808 | tmp0 += z1; | |
809 | tmp1 = z4 + z5; | |
810 | tmp2 = z3 + z5; | |
811 | tmp3 += z1; | |
812 | } else { | |
813 | /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */ | |
814 | tmp0 = MULTIPLY(-d7, FIX_1_387039845); | |
815 | tmp1 = MULTIPLY(d7, FIX_1_175875602); | |
816 | tmp2 = MULTIPLY(-d7, FIX_0_785694958); | |
817 | tmp3 = MULTIPLY(d7, FIX_0_275899380); | |
818 | } | |
819 | } | |
820 | } | |
821 | } else { | |
822 | if (d5) { | |
823 | if (d3) { | |
824 | if (d1) { | |
825 | /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */ | |
826 | z2 = d5 + d3; | |
827 | z4 = d5 + d1; | |
828 | z5 = MULTIPLY(d3 + z4, FIX_1_175875602); | |
829 | ||
830 | tmp1 = MULTIPLY(d5, FIX_2_053119869); | |
831 | tmp2 = MULTIPLY(d3, FIX_3_072711026); | |
832 | tmp3 = MULTIPLY(d1, FIX_1_501321110); | |
833 | z1 = MULTIPLY(-d1, FIX_0_899976223); | |
834 | z2 = MULTIPLY(-z2, FIX_2_562915447); | |
835 | z3 = MULTIPLY(-d3, FIX_1_961570560); | |
836 | z4 = MULTIPLY(-z4, FIX_0_390180644); | |
837 | ||
838 | z3 += z5; | |
839 | z4 += z5; | |
840 | ||
841 | tmp0 = z1 + z3; | |
842 | tmp1 += z2 + z4; | |
843 | tmp2 += z2 + z3; | |
844 | tmp3 += z1 + z4; | |
845 | } else { | |
846 | /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */ | |
847 | z2 = d5 + d3; | |
848 | ||
849 | z5 = MULTIPLY(z2, FIX_1_175875602); | |
850 | tmp1 = MULTIPLY(d5, FIX_1_662939225); | |
851 | z4 = MULTIPLY(-d5, FIX_0_390180644); | |
852 | z2 = MULTIPLY(-z2, FIX_1_387039845); | |
853 | tmp2 = MULTIPLY(d3, FIX_1_111140466); | |
854 | z3 = MULTIPLY(-d3, FIX_1_961570560); | |
855 | ||
856 | tmp0 = z3 + z5; | |
857 | tmp1 += z2; | |
858 | tmp2 += z2; | |
859 | tmp3 = z4 + z5; | |
860 | } | |
861 | } else { | |
862 | if (d1) { | |
863 | /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */ | |
864 | z4 = d5 + d1; | |
865 | ||
866 | z5 = MULTIPLY(z4, FIX_1_175875602); | |
867 | z1 = MULTIPLY(-d1, FIX_0_899976223); | |
868 | tmp3 = MULTIPLY(d1, FIX_0_601344887); | |
869 | tmp1 = MULTIPLY(-d5, FIX_0_509795579); | |
870 | z2 = MULTIPLY(-d5, FIX_2_562915447); | |
871 | z4 = MULTIPLY(z4, FIX_0_785694958); | |
872 | ||
873 | tmp0 = z1 + z5; | |
874 | tmp1 += z4; | |
875 | tmp2 = z2 + z5; | |
876 | tmp3 += z4; | |
877 | } else { | |
878 | /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */ | |
879 | tmp0 = MULTIPLY(d5, FIX_1_175875602); | |
880 | tmp1 = MULTIPLY(d5, FIX_0_275899380); | |
881 | tmp2 = MULTIPLY(-d5, FIX_1_387039845); | |
882 | tmp3 = MULTIPLY(d5, FIX_0_785694958); | |
883 | } | |
884 | } | |
885 | } else { | |
886 | if (d3) { | |
887 | if (d1) { | |
888 | /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */ | |
889 | z5 = d1 + d3; | |
890 | tmp3 = MULTIPLY(d1, FIX_0_211164243); | |
891 | tmp2 = MULTIPLY(-d3, FIX_1_451774981); | |
892 | z1 = MULTIPLY(d1, FIX_1_061594337); | |
893 | z2 = MULTIPLY(-d3, FIX_2_172734803); | |
894 | z4 = MULTIPLY(z5, FIX_0_785694958); | |
895 | z5 = MULTIPLY(z5, FIX_1_175875602); | |
896 | ||
897 | tmp0 = z1 - z4; | |
898 | tmp1 = z2 + z4; | |
899 | tmp2 += z5; | |
900 | tmp3 += z5; | |
901 | } else { | |
902 | /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */ | |
903 | tmp0 = MULTIPLY(-d3, FIX_0_785694958); | |
904 | tmp1 = MULTIPLY(-d3, FIX_1_387039845); | |
905 | tmp2 = MULTIPLY(-d3, FIX_0_275899380); | |
906 | tmp3 = MULTIPLY(d3, FIX_1_175875602); | |
907 | } | |
908 | } else { | |
909 | if (d1) { | |
910 | /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */ | |
911 | tmp0 = MULTIPLY(d1, FIX_0_275899380); | |
912 | tmp1 = MULTIPLY(d1, FIX_0_785694958); | |
913 | tmp2 = MULTIPLY(d1, FIX_1_175875602); | |
914 | tmp3 = MULTIPLY(d1, FIX_1_387039845); | |
915 | } else { | |
916 | /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */ | |
917 | tmp0 = tmp1 = tmp2 = tmp3 = 0; | |
918 | } | |
919 | } | |
920 | } | |
921 | } | |
922 | ||
923 | /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ | |
924 | ||
925 | dataptr[DCTSIZE*0] = (int16_t) DESCALE(tmp10 + tmp3, | |
926 | CONST_BITS+PASS1_BITS+3); | |
927 | dataptr[DCTSIZE*7] = (int16_t) DESCALE(tmp10 - tmp3, | |
928 | CONST_BITS+PASS1_BITS+3); | |
929 | dataptr[DCTSIZE*1] = (int16_t) DESCALE(tmp11 + tmp2, | |
930 | CONST_BITS+PASS1_BITS+3); | |
931 | dataptr[DCTSIZE*6] = (int16_t) DESCALE(tmp11 - tmp2, | |
932 | CONST_BITS+PASS1_BITS+3); | |
933 | dataptr[DCTSIZE*2] = (int16_t) DESCALE(tmp12 + tmp1, | |
934 | CONST_BITS+PASS1_BITS+3); | |
935 | dataptr[DCTSIZE*5] = (int16_t) DESCALE(tmp12 - tmp1, | |
936 | CONST_BITS+PASS1_BITS+3); | |
937 | dataptr[DCTSIZE*3] = (int16_t) DESCALE(tmp13 + tmp0, | |
938 | CONST_BITS+PASS1_BITS+3); | |
939 | dataptr[DCTSIZE*4] = (int16_t) DESCALE(tmp13 - tmp0, | |
940 | CONST_BITS+PASS1_BITS+3); | |
941 | ||
942 | dataptr++; /* advance pointer to next column */ | |
943 | } | |
944 | } | |
945 | ||
946 | #undef DCTSIZE | |
947 | #define DCTSIZE 4 | |
948 | #define DCTSTRIDE 8 | |
949 | ||
950 | void ff_j_rev_dct4(DCTBLOCK data) | |
951 | { | |
952 | int32_t tmp0, tmp1, tmp2, tmp3; | |
953 | int32_t tmp10, tmp11, tmp12, tmp13; | |
954 | int32_t z1; | |
955 | int32_t d0, d2, d4, d6; | |
956 | register int16_t *dataptr; | |
957 | int rowctr; | |
958 | ||
959 | /* Pass 1: process rows. */ | |
960 | /* Note results are scaled up by sqrt(8) compared to a true IDCT; */ | |
961 | /* furthermore, we scale the results by 2**PASS1_BITS. */ | |
962 | ||
963 | data[0] += 4; | |
964 | ||
965 | dataptr = data; | |
966 | ||
967 | for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { | |
968 | /* Due to quantization, we will usually find that many of the input | |
969 | * coefficients are zero, especially the AC terms. We can exploit this | |
970 | * by short-circuiting the IDCT calculation for any row in which all | |
971 | * the AC terms are zero. In that case each output is equal to the | |
972 | * DC coefficient (with scale factor as needed). | |
973 | * With typical images and quantization tables, half or more of the | |
974 | * row DCT calculations can be simplified this way. | |
975 | */ | |
976 | ||
977 | register int *idataptr = (int*)dataptr; | |
978 | ||
979 | d0 = dataptr[0]; | |
980 | d2 = dataptr[1]; | |
981 | d4 = dataptr[2]; | |
982 | d6 = dataptr[3]; | |
983 | ||
984 | if ((d2 | d4 | d6) == 0) { | |
985 | /* AC terms all zero */ | |
986 | if (d0) { | |
987 | /* Compute a 32 bit value to assign. */ | |
988 | int16_t dcval = (int16_t) (d0 << PASS1_BITS); | |
989 | register int v = (dcval & 0xffff) | ((dcval << 16) & 0xffff0000); | |
990 | ||
991 | idataptr[0] = v; | |
992 | idataptr[1] = v; | |
993 | } | |
994 | ||
995 | dataptr += DCTSTRIDE; /* advance pointer to next row */ | |
996 | continue; | |
997 | } | |
998 | ||
999 | /* Even part: reverse the even part of the forward DCT. */ | |
1000 | /* The rotator is sqrt(2)*c(-6). */ | |
1001 | if (d6) { | |
1002 | if (d2) { | |
1003 | /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ | |
1004 | z1 = MULTIPLY(d2 + d6, FIX_0_541196100); | |
1005 | tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); | |
1006 | tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); | |
1007 | ||
1008 | tmp0 = (d0 + d4) << CONST_BITS; | |
1009 | tmp1 = (d0 - d4) << CONST_BITS; | |
1010 | ||
1011 | tmp10 = tmp0 + tmp3; | |
1012 | tmp13 = tmp0 - tmp3; | |
1013 | tmp11 = tmp1 + tmp2; | |
1014 | tmp12 = tmp1 - tmp2; | |
1015 | } else { | |
1016 | /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ | |
1017 | tmp2 = MULTIPLY(-d6, FIX_1_306562965); | |
1018 | tmp3 = MULTIPLY(d6, FIX_0_541196100); | |
1019 | ||
1020 | tmp0 = (d0 + d4) << CONST_BITS; | |
1021 | tmp1 = (d0 - d4) << CONST_BITS; | |
1022 | ||
1023 | tmp10 = tmp0 + tmp3; | |
1024 | tmp13 = tmp0 - tmp3; | |
1025 | tmp11 = tmp1 + tmp2; | |
1026 | tmp12 = tmp1 - tmp2; | |
1027 | } | |
1028 | } else { | |
1029 | if (d2) { | |
1030 | /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ | |
1031 | tmp2 = MULTIPLY(d2, FIX_0_541196100); | |
1032 | tmp3 = MULTIPLY(d2, FIX_1_306562965); | |
1033 | ||
1034 | tmp0 = (d0 + d4) << CONST_BITS; | |
1035 | tmp1 = (d0 - d4) << CONST_BITS; | |
1036 | ||
1037 | tmp10 = tmp0 + tmp3; | |
1038 | tmp13 = tmp0 - tmp3; | |
1039 | tmp11 = tmp1 + tmp2; | |
1040 | tmp12 = tmp1 - tmp2; | |
1041 | } else { | |
1042 | /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ | |
1043 | tmp10 = tmp13 = (d0 + d4) << CONST_BITS; | |
1044 | tmp11 = tmp12 = (d0 - d4) << CONST_BITS; | |
1045 | } | |
1046 | } | |
1047 | ||
1048 | /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ | |
1049 | ||
1050 | dataptr[0] = (int16_t) DESCALE(tmp10, CONST_BITS-PASS1_BITS); | |
1051 | dataptr[1] = (int16_t) DESCALE(tmp11, CONST_BITS-PASS1_BITS); | |
1052 | dataptr[2] = (int16_t) DESCALE(tmp12, CONST_BITS-PASS1_BITS); | |
1053 | dataptr[3] = (int16_t) DESCALE(tmp13, CONST_BITS-PASS1_BITS); | |
1054 | ||
1055 | dataptr += DCTSTRIDE; /* advance pointer to next row */ | |
1056 | } | |
1057 | ||
1058 | /* Pass 2: process columns. */ | |
1059 | /* Note that we must descale the results by a factor of 8 == 2**3, */ | |
1060 | /* and also undo the PASS1_BITS scaling. */ | |
1061 | ||
1062 | dataptr = data; | |
1063 | for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) { | |
1064 | /* Columns of zeroes can be exploited in the same way as we did with rows. | |
1065 | * However, the row calculation has created many nonzero AC terms, so the | |
1066 | * simplification applies less often (typically 5% to 10% of the time). | |
1067 | * On machines with very fast multiplication, it's possible that the | |
1068 | * test takes more time than it's worth. In that case this section | |
1069 | * may be commented out. | |
1070 | */ | |
1071 | ||
1072 | d0 = dataptr[DCTSTRIDE*0]; | |
1073 | d2 = dataptr[DCTSTRIDE*1]; | |
1074 | d4 = dataptr[DCTSTRIDE*2]; | |
1075 | d6 = dataptr[DCTSTRIDE*3]; | |
1076 | ||
1077 | /* Even part: reverse the even part of the forward DCT. */ | |
1078 | /* The rotator is sqrt(2)*c(-6). */ | |
1079 | if (d6) { | |
1080 | if (d2) { | |
1081 | /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */ | |
1082 | z1 = MULTIPLY(d2 + d6, FIX_0_541196100); | |
1083 | tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065); | |
1084 | tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865); | |
1085 | ||
1086 | tmp0 = (d0 + d4) << CONST_BITS; | |
1087 | tmp1 = (d0 - d4) << CONST_BITS; | |
1088 | ||
1089 | tmp10 = tmp0 + tmp3; | |
1090 | tmp13 = tmp0 - tmp3; | |
1091 | tmp11 = tmp1 + tmp2; | |
1092 | tmp12 = tmp1 - tmp2; | |
1093 | } else { | |
1094 | /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */ | |
1095 | tmp2 = MULTIPLY(-d6, FIX_1_306562965); | |
1096 | tmp3 = MULTIPLY(d6, FIX_0_541196100); | |
1097 | ||
1098 | tmp0 = (d0 + d4) << CONST_BITS; | |
1099 | tmp1 = (d0 - d4) << CONST_BITS; | |
1100 | ||
1101 | tmp10 = tmp0 + tmp3; | |
1102 | tmp13 = tmp0 - tmp3; | |
1103 | tmp11 = tmp1 + tmp2; | |
1104 | tmp12 = tmp1 - tmp2; | |
1105 | } | |
1106 | } else { | |
1107 | if (d2) { | |
1108 | /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */ | |
1109 | tmp2 = MULTIPLY(d2, FIX_0_541196100); | |
1110 | tmp3 = MULTIPLY(d2, FIX_1_306562965); | |
1111 | ||
1112 | tmp0 = (d0 + d4) << CONST_BITS; | |
1113 | tmp1 = (d0 - d4) << CONST_BITS; | |
1114 | ||
1115 | tmp10 = tmp0 + tmp3; | |
1116 | tmp13 = tmp0 - tmp3; | |
1117 | tmp11 = tmp1 + tmp2; | |
1118 | tmp12 = tmp1 - tmp2; | |
1119 | } else { | |
1120 | /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */ | |
1121 | tmp10 = tmp13 = (d0 + d4) << CONST_BITS; | |
1122 | tmp11 = tmp12 = (d0 - d4) << CONST_BITS; | |
1123 | } | |
1124 | } | |
1125 | ||
1126 | /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ | |
1127 | ||
1128 | dataptr[DCTSTRIDE*0] = tmp10 >> (CONST_BITS+PASS1_BITS+3); | |
1129 | dataptr[DCTSTRIDE*1] = tmp11 >> (CONST_BITS+PASS1_BITS+3); | |
1130 | dataptr[DCTSTRIDE*2] = tmp12 >> (CONST_BITS+PASS1_BITS+3); | |
1131 | dataptr[DCTSTRIDE*3] = tmp13 >> (CONST_BITS+PASS1_BITS+3); | |
1132 | ||
1133 | dataptr++; /* advance pointer to next column */ | |
1134 | } | |
1135 | } | |
1136 | ||
1137 | void ff_j_rev_dct2(DCTBLOCK data){ | |
1138 | int d00, d01, d10, d11; | |
1139 | ||
1140 | data[0] += 4; | |
1141 | d00 = data[0+0*DCTSTRIDE] + data[1+0*DCTSTRIDE]; | |
1142 | d01 = data[0+0*DCTSTRIDE] - data[1+0*DCTSTRIDE]; | |
1143 | d10 = data[0+1*DCTSTRIDE] + data[1+1*DCTSTRIDE]; | |
1144 | d11 = data[0+1*DCTSTRIDE] - data[1+1*DCTSTRIDE]; | |
1145 | ||
1146 | data[0+0*DCTSTRIDE]= (d00 + d10)>>3; | |
1147 | data[1+0*DCTSTRIDE]= (d01 + d11)>>3; | |
1148 | data[0+1*DCTSTRIDE]= (d00 - d10)>>3; | |
1149 | data[1+1*DCTSTRIDE]= (d01 - d11)>>3; | |
1150 | } | |
1151 | ||
1152 | void ff_j_rev_dct1(DCTBLOCK data){ | |
1153 | data[0] = (data[0] + 4)>>3; | |
1154 | } | |
1155 | ||
1156 | #undef FIX | |
1157 | #undef CONST_BITS | |
1158 | ||
1159 | void ff_jref_idct_put(uint8_t *dest, int line_size, int16_t *block) | |
1160 | { | |
1161 | ff_j_rev_dct(block); | |
1162 | ff_put_pixels_clamped(block, dest, line_size); | |
1163 | } | |
1164 | ||
1165 | void ff_jref_idct_add(uint8_t *dest, int line_size, int16_t *block) | |
1166 | { | |
1167 | ff_j_rev_dct(block); | |
1168 | ff_add_pixels_clamped(block, dest, line_size); | |
1169 | } |