FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/xvididct.c
Date: 2022-12-05 20:26:17
Exec Total Coverage
Lines: 198 205 96.6%
Functions: 6 8 75.0%
Branches: 33 38 86.8%

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1 /*
2 * Xvid MPEG-4 IDCT
3 *
4 * Copyright (C) 2006-2011 Xvid Solutions GmbH
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * Walken IDCT
26 * Alternative IDCT implementation for decoding compatibility.
27 *
28 * @author Skal
29 * @note This C version is not the original IDCT, but a modified one that
30 * yields the same error profile as the MMX/MMXEXT/SSE2 versions.
31 */
32
33 #include "config.h"
34 #include "libavutil/attributes.h"
35 #include "avcodec.h"
36 #include "idctdsp.h"
37 #include "xvididct.h"
38
39 #define ROW_SHIFT 11
40 #define COL_SHIFT 6
41
42 // #define FIX(x) (int)((x) * (1 << ROW_SHIFT))
43 #define RND0 65536 // 1 << (COL_SHIFT + ROW_SHIFT - 1);
44 #define RND1 3597 // FIX (1.75683487303);
45 #define RND2 2260 // FIX (1.10355339059);
46 #define RND3 1203 // FIX (0.587788325588);
47 #define RND4 0
48 #define RND5 120 // FIX (0.058658283817);
49 #define RND6 512 // FIX (0.25);
50 #define RND7 512 // FIX (0.25);
51
52 static const int TAB04[] = { 22725, 21407, 19266, 16384, 12873, 8867, 4520 };
53 static const int TAB17[] = { 31521, 29692, 26722, 22725, 17855, 12299, 6270 };
54 static const int TAB26[] = { 29692, 27969, 25172, 21407, 16819, 11585, 5906 };
55 static const int TAB35[] = { 26722, 25172, 22654, 19266, 15137, 10426, 5315 };
56
57 480000 static int idct_row(short *in, const int *const tab, int rnd)
58 {
59 480000 const int c1 = tab[0];
60 480000 const int c2 = tab[1];
61 480000 const int c3 = tab[2];
62 480000 const int c4 = tab[3];
63 480000 const int c5 = tab[4];
64 480000 const int c6 = tab[5];
65 480000 const int c7 = tab[6];
66
67 480000 const int right = in[5] | in[6] | in[7];
68 480000 const int left = in[1] | in[2] | in[3];
69
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480000 if (!(right | in[4])) {
70 264353 const int k = c4 * in[0] + rnd;
71
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264353 if (left) {
72 24730 const int a0 = k + c2 * in[2];
73 24730 const int a1 = k + c6 * in[2];
74 24730 const int a2 = k - c6 * in[2];
75 24730 const int a3 = k - c2 * in[2];
76
77 24730 const int b0 = c1 * in[1] + c3 * in[3];
78 24730 const int b1 = c3 * in[1] - c7 * in[3];
79 24730 const int b2 = c5 * in[1] - c1 * in[3];
80 24730 const int b3 = c7 * in[1] - c5 * in[3];
81
82 24730 in[0] = (a0 + b0) >> ROW_SHIFT;
83 24730 in[1] = (a1 + b1) >> ROW_SHIFT;
84 24730 in[2] = (a2 + b2) >> ROW_SHIFT;
85 24730 in[3] = (a3 + b3) >> ROW_SHIFT;
86 24730 in[4] = (a3 - b3) >> ROW_SHIFT;
87 24730 in[5] = (a2 - b2) >> ROW_SHIFT;
88 24730 in[6] = (a1 - b1) >> ROW_SHIFT;
89 24730 in[7] = (a0 - b0) >> ROW_SHIFT;
90 } else {
91 239623 const int a0 = k >> ROW_SHIFT;
92
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239623 if (a0) {
93 97939 in[0] =
94 97939 in[1] =
95 97939 in[2] =
96 97939 in[3] =
97 97939 in[4] =
98 97939 in[5] =
99 97939 in[6] =
100 97939 in[7] = a0;
101 } else
102 141684 return 0;
103 }
104
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215647 } else if (!(left | right)) {
105 7429 const int a0 = (rnd + c4 * (in[0] + in[4])) >> ROW_SHIFT;
106 7429 const int a1 = (rnd + c4 * (in[0] - in[4])) >> ROW_SHIFT;
107
108 7429 in[0] = a0;
109 7429 in[3] = a0;
110 7429 in[4] = a0;
111 7429 in[7] = a0;
112 7429 in[1] = a1;
113 7429 in[2] = a1;
114 7429 in[5] = a1;
115 7429 in[6] = a1;
116 } else {
117 208218 const int k = c4 * in[0] + rnd;
118 208218 const unsigned int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6];
119 208218 const unsigned int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6];
120 208218 const unsigned int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6];
121 208218 const unsigned int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6];
122
123 208218 const unsigned int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7];
124 208218 const unsigned int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7];
125 208218 const unsigned int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7];
126 208218 const unsigned int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7];
127
128 208218 in[0] = (int)(a0 + b0) >> ROW_SHIFT;
129 208218 in[1] = (int)(a1 + b1) >> ROW_SHIFT;
130 208218 in[2] = (int)(a2 + b2) >> ROW_SHIFT;
131 208218 in[3] = (int)(a3 + b3) >> ROW_SHIFT;
132 208218 in[4] = (int)(a3 - b3) >> ROW_SHIFT;
133 208218 in[5] = (int)(a2 - b2) >> ROW_SHIFT;
134 208218 in[6] = (int)(a1 - b1) >> ROW_SHIFT;
135 208218 in[7] = (int)(a0 - b0) >> ROW_SHIFT;
136 }
137 338316 return 1;
138 }
139
140 #define TAN1 0x32EC
141 #define TAN2 0x6A0A
142 #define TAN3 0xAB0E
143 #define SQRT2 0x5A82
144
145 #define MULT(c, x, n) ((unsigned)((int)((c) * (unsigned)(x)) >> (n)))
146 // 12b version => #define MULT(c,x, n) ((((c) >> 3) * (x)) >> ((n) - 3))
147 // 12b zero-testing version:
148
149 #define BUTTERFLY(a, b, tmp) \
150 (tmp) = (a) + (b); \
151 (b) = (a) - (b); \
152 (a) = (tmp)
153
154 #define LOAD_BUTTERFLY(m1, m2, a, b, tmp, s) \
155 (m1) = (s)[(a)] + (s)[(b)]; \
156 (m2) = (s)[(a)] - (s)[(b)]
157
158 384504 static void idct_col_8(short *const in)
159 {
160 int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
161
162 // odd
163
164 384504 mm4 = (int) in[7 * 8];
165 384504 mm5 = (int) in[5 * 8];
166 384504 mm6 = (int) in[3 * 8];
167 384504 mm7 = (int) in[1 * 8];
168
169 384504 mm0 = MULT(TAN1, mm4, 16) + mm7;
170 384504 mm1 = MULT(TAN1, mm7, 16) - mm4;
171 384504 mm2 = MULT(TAN3, mm5, 16) + mm6;
172 384504 mm3 = MULT(TAN3, mm6, 16) - mm5;
173
174 384504 mm7 = mm0 + mm2;
175 384504 mm4 = mm1 - mm3;
176 384504 mm0 = mm0 - mm2;
177 384504 mm1 = mm1 + mm3;
178 384504 mm6 = mm0 + mm1;
179 384504 mm5 = mm0 - mm1;
180 384504 mm5 = 2 * MULT(SQRT2, mm5, 16); // 2*sqrt2
181 384504 mm6 = 2 * MULT(SQRT2, mm6, 16); // Watch out: precision loss but done to match
182 // the pmulhw used in MMX/MMXEXT/SSE2 versions
183
184 // even
185
186 384504 mm1 = (int) in[2 * 8];
187 384504 mm2 = (int) in[6 * 8];
188 384504 mm3 = MULT(TAN2, mm2, 16) + mm1;
189 384504 mm2 = MULT(TAN2, mm1, 16) - mm2;
190
191 384504 LOAD_BUTTERFLY(mm0, mm1, 0 * 8, 4 * 8, spill, in);
192
193 384504 BUTTERFLY(mm0, mm3, spill);
194 384504 BUTTERFLY(mm0, mm7, spill);
195 384504 in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
196 384504 in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
197 384504 BUTTERFLY(mm3, mm4, mm0);
198 384504 in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
199 384504 in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
200
201 384504 BUTTERFLY(mm1, mm2, mm0);
202 384504 BUTTERFLY(mm1, mm6, mm0);
203 384504 in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
204 384504 in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
205 384504 BUTTERFLY(mm2, mm5, mm0);
206 384504 in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
207 384504 in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
208 384504 }
209
210 5896 static void idct_col_4(short *const in)
211 {
212 int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
213
214 // odd
215
216 5896 mm0 = (int) in[1 * 8];
217 5896 mm2 = (int) in[3 * 8];
218
219 5896 mm1 = MULT(TAN1, mm0, 16);
220 5896 mm3 = MULT(TAN3, mm2, 16);
221
222 5896 mm7 = mm0 + mm2;
223 5896 mm4 = mm1 - mm3;
224 5896 mm0 = mm0 - mm2;
225 5896 mm1 = mm1 + mm3;
226 5896 mm6 = mm0 + mm1;
227 5896 mm5 = mm0 - mm1;
228 5896 mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
229 5896 mm5 = 2 * MULT(SQRT2, mm5, 16);
230
231 // even
232
233 5896 mm0 = mm1 = (int) in[0 * 8];
234 5896 mm3 = (int) in[2 * 8];
235 5896 mm2 = MULT(TAN2, mm3, 16);
236
237 5896 BUTTERFLY(mm0, mm3, spill);
238 5896 BUTTERFLY(mm0, mm7, spill);
239 5896 in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
240 5896 in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
241 5896 BUTTERFLY(mm3, mm4, mm0);
242 5896 in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
243 5896 in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
244
245 5896 BUTTERFLY(mm1, mm2, mm0);
246 5896 BUTTERFLY(mm1, mm6, mm0);
247 5896 in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
248 5896 in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
249 5896 BUTTERFLY(mm2, mm5, mm0);
250 5896 in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
251 5896 in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
252 5896 }
253
254 89600 static void idct_col_3(short *const in)
255 {
256 int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
257
258 // odd
259
260 89600 mm7 = (int) in[1 * 8];
261 89600 mm4 = MULT(TAN1, mm7, 16);
262
263 89600 mm6 = mm7 + mm4;
264 89600 mm5 = mm7 - mm4;
265 89600 mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
266 89600 mm5 = 2 * MULT(SQRT2, mm5, 16);
267
268 // even
269
270 89600 mm0 = mm1 = (int) in[0 * 8];
271 89600 mm3 = (int) in[2 * 8];
272 89600 mm2 = MULT(TAN2, mm3, 16);
273
274 89600 BUTTERFLY(mm0, mm3, spill);
275 89600 BUTTERFLY(mm0, mm7, spill);
276 89600 in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
277 89600 in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
278 89600 BUTTERFLY(mm3, mm4, mm0);
279 89600 in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
280 89600 in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
281
282 89600 BUTTERFLY(mm1, mm2, mm0);
283 89600 BUTTERFLY(mm1, mm6, mm0);
284 89600 in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
285 89600 in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
286 89600 BUTTERFLY(mm2, mm5, mm0);
287 89600 in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
288 89600 in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
289 89600 }
290
291 60000 void ff_xvid_idct(int16_t *const in)
292 {
293 60000 int i, rows = 0x07;
294
295 60000 idct_row(in + 0 * 8, TAB04, RND0);
296 60000 idct_row(in + 1 * 8, TAB17, RND1);
297 60000 idct_row(in + 2 * 8, TAB26, RND2);
298
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60000 if (idct_row(in + 3 * 8, TAB35, RND3))
299 29558 rows |= 0x08;
300
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60000 if (idct_row(in + 4 * 8, TAB04, RND4))
301 29661 rows |= 0x10;
302
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60000 if (idct_row(in + 5 * 8, TAB35, RND5))
303 29720 rows |= 0x20;
304
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60000 if (idct_row(in + 6 * 8, TAB26, RND6))
305 29731 rows |= 0x40;
306
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60000 if (idct_row(in + 7 * 8, TAB17, RND7))
307 39653 rows |= 0x80;
308
309
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60000 if (rows & 0xF0) {
310
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432567 for (i = 0; i < 8; i++)
311 384504 idct_col_8(in + i);
312
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11937 } else if (rows & 0x08) {
313
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6633 for (i = 0; i < 8; i++)
314 5896 idct_col_4(in + i);
315 } else {
316
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100800 for (i = 0; i < 8; i++)
317 89600 idct_col_3(in + i);
318 }
319 60000 }
320
321 static void xvid_idct_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
322 {
323 ff_xvid_idct(block);
324 ff_put_pixels_clamped_c(block, dest, line_size);
325 }
326
327 static void xvid_idct_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
328 {
329 ff_xvid_idct(block);
330 ff_add_pixels_clamped_c(block, dest, line_size);
331 }
332
333 4 av_cold void ff_xvid_idct_init(IDCTDSPContext *c, AVCodecContext *avctx)
334 {
335 4 const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8;
336
337
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4 if (high_bit_depth || avctx->lowres ||
338
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4 !(avctx->idct_algo == FF_IDCT_AUTO ||
339
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4 avctx->idct_algo == FF_IDCT_XVID))
340 return;
341
342
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4 if (avctx->idct_algo == FF_IDCT_XVID) {
343 4 c->idct_put = xvid_idct_put;
344 4 c->idct_add = xvid_idct_add;
345 4 c->idct = ff_xvid_idct;
346 4 c->perm_type = FF_IDCT_PERM_NONE;
347 }
348
349 #if ARCH_X86
350 4 ff_xvid_idct_init_x86(c, avctx, high_bit_depth);
351 #elif ARCH_MIPS
352 ff_xvid_idct_init_mips(c, avctx, high_bit_depth);
353 #endif
354
355 4 ff_init_scantable_permutation(c->idct_permutation, c->perm_type);
356 }
357