blob: 89dd9f2fcac6da4cc7b6df6ce974dc2d2be55bce
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, ptrdiff_t 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, ptrdiff_t line_size, int16_t *block) |
1166 | { |
1167 | ff_j_rev_dct(block); |
1168 | ff_add_pixels_clamped(block, dest, line_size); |
1169 | } |
1170 |