summaryrefslogtreecommitdiffstats
path: root/libavcodec/xvididct.c
blob: ca89703233facdbcbf2acbef7e1ebc3c81c671d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
/*
 * Xvid MPEG-4 IDCT
 *
 * Copyright (C) 2006-2011 Xvid Solutions GmbH
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Walken IDCT
 * Alternative IDCT implementation for decoding compatibility.
 *
 * @author Skal
 * @note This C version is not the original IDCT, but a modified one that
 *       yields the same error profile as the MMX/MMXEXT/SSE2 versions.
 */

#include "config.h"
#include "libavutil/attributes.h"
#include "avcodec.h"
#include "idctdsp.h"
#include "xvididct.h"

#define ROW_SHIFT 11
#define COL_SHIFT  6

// #define FIX(x)   (int)((x) * (1 << ROW_SHIFT))
#define RND0 65536 // 1 << (COL_SHIFT + ROW_SHIFT - 1);
#define RND1 3597  // FIX (1.75683487303);
#define RND2 2260  // FIX (1.10355339059);
#define RND3 1203  // FIX (0.587788325588);
#define RND4 0
#define RND5 120   // FIX (0.058658283817);
#define RND6 512   // FIX (0.25);
#define RND7 512   // FIX (0.25);

static const int TAB04[] = { 22725, 21407, 19266, 16384, 12873,  8867, 4520 };
static const int TAB17[] = { 31521, 29692, 26722, 22725, 17855, 12299, 6270 };
static const int TAB26[] = { 29692, 27969, 25172, 21407, 16819, 11585, 5906 };
static const int TAB35[] = { 26722, 25172, 22654, 19266, 15137, 10426, 5315 };

static int idct_row(short *in, const int *const tab, int rnd)
{
    const int c1 = tab[0];
    const int c2 = tab[1];
    const int c3 = tab[2];
    const int c4 = tab[3];
    const int c5 = tab[4];
    const int c6 = tab[5];
    const int c7 = tab[6];

    const int right = in[5] | in[6] | in[7];
    const int left  = in[1] | in[2] | in[3];
    if (!(right | in[4])) {
        const int k = c4 * in[0] + rnd;
        if (left) {
            const int a0 = k + c2 * in[2];
            const int a1 = k + c6 * in[2];
            const int a2 = k - c6 * in[2];
            const int a3 = k - c2 * in[2];

            const int b0 = c1 * in[1] + c3 * in[3];
            const int b1 = c3 * in[1] - c7 * in[3];
            const int b2 = c5 * in[1] - c1 * in[3];
            const int b3 = c7 * in[1] - c5 * in[3];

            in[0] = (a0 + b0) >> ROW_SHIFT;
            in[1] = (a1 + b1) >> ROW_SHIFT;
            in[2] = (a2 + b2) >> ROW_SHIFT;
            in[3] = (a3 + b3) >> ROW_SHIFT;
            in[4] = (a3 - b3) >> ROW_SHIFT;
            in[5] = (a2 - b2) >> ROW_SHIFT;
            in[6] = (a1 - b1) >> ROW_SHIFT;
            in[7] = (a0 - b0) >> ROW_SHIFT;
        } else {
            const int a0 = k >> ROW_SHIFT;
            if (a0) {
                in[0] =
                in[1] =
                in[2] =
                in[3] =
                in[4] =
                in[5] =
                in[6] =
                in[7] = a0;
            } else
                return 0;
        }
    } else if (!(left | right)) {
        const int a0 = (rnd + c4 * (in[0] + in[4])) >> ROW_SHIFT;
        const int a1 = (rnd + c4 * (in[0] - in[4])) >> ROW_SHIFT;

        in[0] = a0;
        in[3] = a0;
        in[4] = a0;
        in[7] = a0;
        in[1] = a1;
        in[2] = a1;
        in[5] = a1;
        in[6] = a1;
    } else {
        const int k  = c4 * in[0] + rnd;
        const int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6];
        const int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6];
        const int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6];
        const int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6];

        const int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7];
        const int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7];
        const int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7];
        const int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7];

        in[0] = (a0 + b0) >> ROW_SHIFT;
        in[1] = (a1 + b1) >> ROW_SHIFT;
        in[2] = (a2 + b2) >> ROW_SHIFT;
        in[3] = (a3 + b3) >> ROW_SHIFT;
        in[4] = (a3 - b3) >> ROW_SHIFT;
        in[5] = (a2 - b2) >> ROW_SHIFT;
        in[6] = (a1 - b1) >> ROW_SHIFT;
        in[7] = (a0 - b0) >> ROW_SHIFT;
    }
    return 1;
}

#define TAN1  0x32EC
#define TAN2  0x6A0A
#define TAN3  0xAB0E
#define SQRT2 0x5A82

#define MULT(c, x, n)  (((c) * (x)) >> (n))
// 12b version => #define MULT(c,x, n)  ((((c) >> 3) * (x)) >> ((n) - 3))
// 12b zero-testing version:

#define BUTTERFLY(a, b, tmp)     \
    (tmp) = (a) + (b);           \
    (b)   = (a) - (b);           \
    (a)   = (tmp)

#define LOAD_BUTTERFLY(m1, m2, a, b, tmp, s)   \
    (m1) = (s)[(a)] + (s)[(b)];                \
    (m2) = (s)[(a)] - (s)[(b)]

static void idct_col_8(short *const in)
{
    int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;

    // odd

    mm4 = (int) in[7 * 8];
    mm5 = (int) in[5 * 8];
    mm6 = (int) in[3 * 8];
    mm7 = (int) in[1 * 8];

    mm0 = MULT(TAN1, mm4, 16) + mm7;
    mm1 = MULT(TAN1, mm7, 16) - mm4;
    mm2 = MULT(TAN3, mm5, 16) + mm6;
    mm3 = MULT(TAN3, mm6, 16) - mm5;

    mm7 = mm0 + mm2;
    mm4 = mm1 - mm3;
    mm0 = mm0 - mm2;
    mm1 = mm1 + mm3;
    mm6 = mm0 + mm1;
    mm5 = mm0 - mm1;
    mm5 = 2 * MULT(SQRT2, mm5, 16); // 2*sqrt2
    mm6 = 2 * MULT(SQRT2, mm6, 16); // Watch out: precision loss but done to match
                                    // the pmulhw used in MMX/MMXEXT/SSE2 versions

    // even

    mm1 = (int) in[2 * 8];
    mm2 = (int) in[6 * 8];
    mm3 = MULT(TAN2, mm2, 16) + mm1;
    mm2 = MULT(TAN2, mm1, 16) - mm2;

    LOAD_BUTTERFLY(mm0, mm1, 0 * 8, 4 * 8, spill, in);

    BUTTERFLY(mm0, mm3, spill);
    BUTTERFLY(mm0, mm7, spill);
    in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
    in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
    BUTTERFLY(mm3, mm4, mm0);
    in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
    in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);

    BUTTERFLY(mm1, mm2, mm0);
    BUTTERFLY(mm1, mm6, mm0);
    in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
    in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
    BUTTERFLY(mm2, mm5, mm0);
    in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
    in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
}

static void idct_col_4(short *const in)
{
    int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;

    // odd

    mm0 = (int) in[1 * 8];
    mm2 = (int) in[3 * 8];

    mm1 = MULT(TAN1, mm0, 16);
    mm3 = MULT(TAN3, mm2, 16);

    mm7 = mm0 + mm2;
    mm4 = mm1 - mm3;
    mm0 = mm0 - mm2;
    mm1 = mm1 + mm3;
    mm6 = mm0 + mm1;
    mm5 = mm0 - mm1;
    mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
    mm5 = 2 * MULT(SQRT2, mm5, 16);

    // even

    mm0 = mm1 = (int) in[0 * 8];
    mm3 = (int) in[2 * 8];
    mm2 = MULT(TAN2, mm3, 16);

    BUTTERFLY(mm0, mm3, spill);
    BUTTERFLY(mm0, mm7, spill);
    in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
    in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
    BUTTERFLY(mm3, mm4, mm0);
    in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
    in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);

    BUTTERFLY(mm1, mm2, mm0);
    BUTTERFLY(mm1, mm6, mm0);
    in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
    in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
    BUTTERFLY(mm2, mm5, mm0);
    in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
    in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
}

static void idct_col_3(short *const in)
{
    int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;

    // odd

    mm7 = (int) in[1 * 8];
    mm4 = MULT(TAN1, mm7, 16);

    mm6 = mm7 + mm4;
    mm5 = mm7 - mm4;
    mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
    mm5 = 2 * MULT(SQRT2, mm5, 16);

    // even

    mm0 = mm1 = (int) in[0 * 8];
    mm3 = (int) in[2 * 8];
    mm2 = MULT(TAN2, mm3, 16);

    BUTTERFLY(mm0, mm3, spill);
    BUTTERFLY(mm0, mm7, spill);
    in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
    in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
    BUTTERFLY(mm3, mm4, mm0);
    in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
    in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);

    BUTTERFLY(mm1, mm2, mm0);
    BUTTERFLY(mm1, mm6, mm0);
    in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
    in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
    BUTTERFLY(mm2, mm5, mm0);
    in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
    in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
}

void ff_xvid_idct(int16_t *const in)
{
    int i, rows = 0x07;

    idct_row(in + 0 * 8, TAB04, RND0);
    idct_row(in + 1 * 8, TAB17, RND1);
    idct_row(in + 2 * 8, TAB26, RND2);
    if (idct_row(in + 3 * 8, TAB35, RND3))
        rows |= 0x08;
    if (idct_row(in + 4 * 8, TAB04, RND4))
        rows |= 0x10;
    if (idct_row(in + 5 * 8, TAB35, RND5))
        rows |= 0x20;
    if (idct_row(in + 6 * 8, TAB26, RND6))
        rows |= 0x40;
    if (idct_row(in + 7 * 8, TAB17, RND7))
        rows |= 0x80;

    if (rows & 0xF0) {
        for (i = 0; i < 8; i++)
            idct_col_8(in + i);
    } else if (rows & 0x08) {
        for (i = 0; i < 8; i++)
            idct_col_4(in + i);
    } else {
        for (i = 0; i < 8; i++)
            idct_col_3(in + i);
    }
}

static void xvid_idct_put(uint8_t *dest, int line_size, int16_t *block)
{
    ff_xvid_idct(block);
    ff_put_pixels_clamped(block, dest, line_size);
}

static void xvid_idct_add(uint8_t *dest, int line_size, int16_t *block)
{
    ff_xvid_idct(block);
    ff_add_pixels_clamped(block, dest, line_size);
}

av_cold void ff_xvid_idct_init(IDCTDSPContext *c, AVCodecContext *avctx)
{
    const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8;

    if (!high_bit_depth &&
        (avctx->idct_algo == FF_IDCT_AUTO ||
         avctx->idct_algo == FF_IDCT_XVID)) {
        c->idct_put  = xvid_idct_put;
        c->idct_add  = xvid_idct_add;
        c->idct      = ff_xvid_idct;
        c->perm_type = FF_IDCT_PERM_NONE;
    }

    if (ARCH_X86)
        ff_xvid_idct_init_x86(c, avctx, high_bit_depth);

    ff_init_scantable_permutation(c->idct_permutation, c->perm_type);
}
OpenPOWER on IntegriCloud