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ffmpeg / libavcodec / imgresample.c @ d771bcae

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1
/*
2
 * High quality image resampling with polyphase filters 
3
 * Copyright (c) 2001 Gerard Lantau.
4
 *
5
 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
8
 * (at your option) any later version.
9
 *
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 * This program is distributed in the hope that it will be useful,
11
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13
 * GNU General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU General Public License
16
 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18
 */
19
#include <stdlib.h>
20
#include <stdio.h>
21
#include <string.h>
22
#include <math.h>
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#include "dsputil.h"
24
#include "avcodec.h"
25

    
26
#define NB_COMPONENTS 3
27

    
28
#define PHASE_BITS 4
29
#define NB_PHASES  (1 << PHASE_BITS)
30
#define NB_TAPS    4
31
#define FCENTER    1  /* index of the center of the filter */
32

    
33
#define POS_FRAC_BITS 16
34
#define POS_FRAC      (1 << POS_FRAC_BITS)
35
/* 6 bits precision is needed for MMX */
36
#define FILTER_BITS   8
37

    
38
#define LINE_BUF_HEIGHT (NB_TAPS * 4)
39

    
40
struct ImgReSampleContext {
41
    int iwidth, iheight, owidth, oheight;
42
    int h_incr, v_incr;
43
    INT16 h_filters[NB_PHASES][NB_TAPS] __align8; /* horizontal filters */
44
    INT16 v_filters[NB_PHASES][NB_TAPS] __align8; /* vertical filters */
45
    UINT8 *line_buf;
46
};
47

    
48
static inline int get_phase(int pos)
49
{
50
    return ((pos) >> (POS_FRAC_BITS - PHASE_BITS)) & ((1 << PHASE_BITS) - 1);
51
}
52

    
53
/* This function must be optimized */
54
static void h_resample_fast(UINT8 *dst, int dst_width, UINT8 *src, int src_width,
55
                            int src_start, int src_incr, INT16 *filters)
56
{
57
    int src_pos, phase, sum, i;
58
    UINT8 *s;
59
    INT16 *filter;
60

    
61
    src_pos = src_start;
62
    for(i=0;i<dst_width;i++) {
63
#ifdef TEST
64
        /* test */
65
        if ((src_pos >> POS_FRAC_BITS) < 0 ||
66
            (src_pos >> POS_FRAC_BITS) > (src_width - NB_TAPS))
67
            abort();
68
#endif
69
        s = src + (src_pos >> POS_FRAC_BITS);
70
        phase = get_phase(src_pos);
71
        filter = filters + phase * NB_TAPS;
72
#if NB_TAPS == 4
73
        sum = s[0] * filter[0] +
74
            s[1] * filter[1] +
75
            s[2] * filter[2] +
76
            s[3] * filter[3];
77
#else
78
        {
79
            int j;
80
            sum = 0;
81
            for(j=0;j<NB_TAPS;j++)
82
                sum += s[j] * filter[j];
83
        }
84
#endif
85
        sum = sum >> FILTER_BITS;
86
        if (sum < 0)
87
            sum = 0;
88
        else if (sum > 255)
89
            sum = 255;
90
        dst[0] = sum;
91
        src_pos += src_incr;
92
        dst++;
93
    }
94
}
95

    
96
/* This function must be optimized */
97
static void v_resample(UINT8 *dst, int dst_width, UINT8 *src, int wrap, 
98
                       INT16 *filter)
99
{
100
    int sum, i;
101
    UINT8 *s;
102

    
103
    s = src;
104
    for(i=0;i<dst_width;i++) {
105
#if NB_TAPS == 4
106
        sum = s[0 * wrap] * filter[0] +
107
            s[1 * wrap] * filter[1] +
108
            s[2 * wrap] * filter[2] +
109
            s[3 * wrap] * filter[3];
110
#else
111
        {
112
            int j;
113
            UINT8 *s1 = s;
114

    
115
            sum = 0;
116
            for(j=0;j<NB_TAPS;j++) {
117
                sum += s1[0] * filter[j];
118
                s1 += wrap;
119
            }
120
        }
121
#endif
122
        sum = sum >> FILTER_BITS;
123
        if (sum < 0)
124
            sum = 0;
125
        else if (sum > 255)
126
            sum = 255;
127
        dst[0] = sum;
128
        dst++;
129
        s++;
130
    }
131
}
132

    
133
#ifdef HAVE_MMX
134

    
135
#include "i386/mmx.h"
136

    
137
#define FILTER4(reg) \
138
{\
139
        s = src + (src_pos >> POS_FRAC_BITS);\
140
        phase = get_phase(src_pos);\
141
        filter = filters + phase * NB_TAPS;\
142
        movq_m2r(*s, reg);\
143
        punpcklbw_r2r(mm7, reg);\
144
        movq_m2r(*filter, mm6);\
145
        pmaddwd_r2r(reg, mm6);\
146
        movq_r2r(mm6, reg);\
147
        psrlq_i2r(32, reg);\
148
        paddd_r2r(mm6, reg);\
149
        psrad_i2r(FILTER_BITS, reg);\
150
        src_pos += src_incr;\
151
}
152

    
153
#define DUMP(reg) movq_r2m(reg, tmp); printf(#reg "=%016Lx\n", tmp.uq);
154

    
155
/* XXX: do four pixels at a time */
156
static void h_resample_fast4_mmx(UINT8 *dst, int dst_width, UINT8 *src, int src_width,
157
                                 int src_start, int src_incr, INT16 *filters)
158
{
159
    int src_pos, phase;
160
    UINT8 *s;
161
    INT16 *filter;
162
    mmx_t tmp;
163
    
164
    src_pos = src_start;
165
    pxor_r2r(mm7, mm7);
166

    
167
    while (dst_width >= 4) {
168

    
169
        FILTER4(mm0);
170
        FILTER4(mm1);
171
        FILTER4(mm2);
172
        FILTER4(mm3);
173

    
174
        packuswb_r2r(mm7, mm0);
175
        packuswb_r2r(mm7, mm1);
176
        packuswb_r2r(mm7, mm3);
177
        packuswb_r2r(mm7, mm2);
178
        movq_r2m(mm0, tmp);
179
        dst[0] = tmp.ub[0];
180
        movq_r2m(mm1, tmp);
181
        dst[1] = tmp.ub[0];
182
        movq_r2m(mm2, tmp);
183
        dst[2] = tmp.ub[0];
184
        movq_r2m(mm3, tmp);
185
        dst[3] = tmp.ub[0];
186
        dst += 4;
187
        dst_width -= 4;
188
    }
189
    while (dst_width > 0) {
190
        FILTER4(mm0);
191
        packuswb_r2r(mm7, mm0);
192
        movq_r2m(mm0, tmp);
193
        dst[0] = tmp.ub[0];
194
        dst++;
195
        dst_width--;
196
    }
197
    emms();
198
}
199

    
200
static void v_resample4_mmx(UINT8 *dst, int dst_width, UINT8 *src, int wrap, 
201
                            INT16 *filter)
202
{
203
    int sum, i, v;
204
    UINT8 *s;
205
    mmx_t tmp;
206
    mmx_t coefs[4];
207
    
208
    for(i=0;i<4;i++) {
209
        v = filter[i];
210
        coefs[i].uw[0] = v;
211
        coefs[i].uw[1] = v;
212
        coefs[i].uw[2] = v;
213
        coefs[i].uw[3] = v;
214
    }
215
    
216
    pxor_r2r(mm7, mm7);
217
    s = src;
218
    while (dst_width >= 4) {
219
        movq_m2r(s[0 * wrap], mm0);
220
        punpcklbw_r2r(mm7, mm0);
221
        movq_m2r(s[1 * wrap], mm1);
222
        punpcklbw_r2r(mm7, mm1);
223
        movq_m2r(s[2 * wrap], mm2);
224
        punpcklbw_r2r(mm7, mm2);
225
        movq_m2r(s[3 * wrap], mm3);
226
        punpcklbw_r2r(mm7, mm3);
227

    
228
        pmullw_m2r(coefs[0], mm0);
229
        pmullw_m2r(coefs[1], mm1);
230
        pmullw_m2r(coefs[2], mm2);
231
        pmullw_m2r(coefs[3], mm3);
232

    
233
        paddw_r2r(mm1, mm0);
234
        paddw_r2r(mm3, mm2);
235
        paddw_r2r(mm2, mm0);
236
        psraw_i2r(FILTER_BITS, mm0);
237
        
238
        packuswb_r2r(mm7, mm0);
239
        movq_r2m(mm0, tmp);
240

    
241
        *(UINT32 *)dst = tmp.ud[0];
242
        dst += 4;
243
        s += 4;
244
        dst_width -= 4;
245
    }
246
    while (dst_width > 0) {
247
        sum = s[0 * wrap] * filter[0] +
248
            s[1 * wrap] * filter[1] +
249
            s[2 * wrap] * filter[2] +
250
            s[3 * wrap] * filter[3];
251
        sum = sum >> FILTER_BITS;
252
        if (sum < 0)
253
            sum = 0;
254
        else if (sum > 255)
255
            sum = 255;
256
        dst[0] = sum;
257
        dst++;
258
        s++;
259
        dst_width--;
260
    }
261
    emms();
262
}
263
#endif
264

    
265
/* slow version to handle limit cases. Does not need optimisation */
266
static void h_resample_slow(UINT8 *dst, int dst_width, UINT8 *src, int src_width,
267
                            int src_start, int src_incr, INT16 *filters)
268
{
269
    int src_pos, phase, sum, j, v, i;
270
    UINT8 *s, *src_end;
271
    INT16 *filter;
272

    
273
    src_end = src + src_width;
274
    src_pos = src_start;
275
    for(i=0;i<dst_width;i++) {
276
        s = src + (src_pos >> POS_FRAC_BITS);
277
        phase = get_phase(src_pos);
278
        filter = filters + phase * NB_TAPS;
279
        sum = 0;
280
        for(j=0;j<NB_TAPS;j++) {
281
            if (s < src)
282
                v = src[0];
283
            else if (s >= src_end)
284
                v = src_end[-1];
285
            else
286
                v = s[0];
287
            sum += v * filter[j];
288
            s++;
289
        }
290
        sum = sum >> FILTER_BITS;
291
        if (sum < 0)
292
            sum = 0;
293
        else if (sum > 255)
294
            sum = 255;
295
        dst[0] = sum;
296
        src_pos += src_incr;
297
        dst++;
298
    }
299
}
300

    
301
static void h_resample(UINT8 *dst, int dst_width, UINT8 *src, int src_width,
302
                       int src_start, int src_incr, INT16 *filters)
303
{
304
    int n, src_end;
305

    
306
    if (src_start < 0) {
307
        n = (0 - src_start + src_incr - 1) / src_incr;
308
        h_resample_slow(dst, n, src, src_width, src_start, src_incr, filters);
309
        dst += n;
310
        dst_width -= n;
311
        src_start += n * src_incr;
312
    }
313
    src_end = src_start + dst_width * src_incr;
314
    if (src_end > ((src_width - NB_TAPS) << POS_FRAC_BITS)) {
315
        n = (((src_width - NB_TAPS + 1) << POS_FRAC_BITS) - 1 - src_start) / 
316
            src_incr;
317
    } else {
318
        n = dst_width;
319
    }
320
#ifdef HAVE_MMX
321
    if ((mm_flags & MM_MMX) && NB_TAPS == 4)
322
        h_resample_fast4_mmx(dst, n, 
323
                             src, src_width, src_start, src_incr, filters);
324
    else
325
#endif
326
        h_resample_fast(dst, n, 
327
                        src, src_width, src_start, src_incr, filters);
328
    if (n < dst_width) {
329
        dst += n;
330
        dst_width -= n;
331
        src_start += n * src_incr;
332
        h_resample_slow(dst, dst_width, 
333
                        src, src_width, src_start, src_incr, filters);
334
    }
335
}
336

    
337
static void component_resample(ImgReSampleContext *s, 
338
                               UINT8 *output, int owrap, int owidth, int oheight,
339
                               UINT8 *input, int iwrap, int iwidth, int iheight)
340
{
341
    int src_y, src_y1, last_src_y, ring_y, phase_y, y1, y;
342
    UINT8 *new_line, *src_line;
343

    
344
    last_src_y = - FCENTER - 1;
345
    /* position of the bottom of the filter in the source image */
346
    src_y = (last_src_y + NB_TAPS) * POS_FRAC; 
347
    ring_y = NB_TAPS; /* position in ring buffer */
348
    for(y=0;y<oheight;y++) {
349
        /* apply horizontal filter on new lines from input if needed */
350
        src_y1 = src_y >> POS_FRAC_BITS;
351
        while (last_src_y < src_y1) {
352
            if (++ring_y >= LINE_BUF_HEIGHT + NB_TAPS)
353
                ring_y = NB_TAPS;
354
            last_src_y++;
355
            /* handle limit conditions : replicate line (slighly
356
               inefficient because we filter multiple times */
357
            y1 = last_src_y;
358
            if (y1 < 0) {
359
                y1 = 0;
360
            } else if (y1 >= iheight) {
361
                y1 = iheight - 1;
362
            }
363
            src_line = input + y1 * iwrap;
364
            new_line = s->line_buf + ring_y * owidth;
365
            /* apply filter and handle limit cases correctly */
366
            h_resample(new_line, owidth, 
367
                       src_line, iwidth, - FCENTER * POS_FRAC, s->h_incr, 
368
                       &s->h_filters[0][0]);
369
            /* handle ring buffer wraping */
370
            if (ring_y >= LINE_BUF_HEIGHT) {
371
                memcpy(s->line_buf + (ring_y - LINE_BUF_HEIGHT) * owidth,
372
                       new_line, owidth);
373
            }
374
        }
375
        /* apply vertical filter */
376
        phase_y = get_phase(src_y);
377
#ifdef HAVE_MMX
378
        /* desactivated MMX because loss of precision */
379
        if ((mm_flags & MM_MMX) && NB_TAPS == 4 && 0)
380
            v_resample4_mmx(output, owidth, 
381
                            s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth, 
382
                            &s->v_filters[phase_y][0]);
383
        else
384
#endif
385
            v_resample(output, owidth, 
386
                       s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth, 
387
                       &s->v_filters[phase_y][0]);
388
            
389
        src_y += s->v_incr;
390
        output += owrap;
391
    }
392
}
393

    
394
/* XXX: the following filter is quite naive, but it seems to suffice
395
   for 4 taps */
396
static void build_filter(INT16 *filter, float factor)
397
{
398
    int ph, i, v;
399
    float x, y, tab[NB_TAPS], norm, mult;
400

    
401
    /* if upsampling, only need to interpolate, no filter */
402
    if (factor > 1.0)
403
        factor = 1.0;
404

    
405
    for(ph=0;ph<NB_PHASES;ph++) {
406
        norm = 0;
407
        for(i=0;i<NB_TAPS;i++) {
408
            
409
            x = M_PI * ((float)(i - FCENTER) - (float)ph / NB_PHASES) * factor;
410
            if (x == 0)
411
                y = 1.0;
412
            else
413
                y = sin(x) / x;
414
            tab[i] = y;
415
            norm += y;
416
        }
417

    
418
        /* normalize so that an uniform color remains the same */
419
        mult = (float)(1 << FILTER_BITS) / norm;
420
        for(i=0;i<NB_TAPS;i++) {
421
            v = (int)(tab[i] * mult);
422
            filter[ph * NB_TAPS + i] = v;
423
        }
424
    }
425
}
426

    
427
ImgReSampleContext *img_resample_init(int owidth, int oheight,
428
                                      int iwidth, int iheight)
429
{
430
    ImgReSampleContext *s;
431

    
432
    s = av_mallocz(sizeof(ImgReSampleContext));
433
    if (!s)
434
        return NULL;
435
    s->line_buf = av_mallocz(owidth * (LINE_BUF_HEIGHT + NB_TAPS));
436
    if (!s->line_buf) 
437
        goto fail;
438
    
439
    s->owidth = owidth;
440
    s->oheight = oheight;
441
    s->iwidth = iwidth;
442
    s->iheight = iheight;
443
    
444
    s->h_incr = (iwidth * POS_FRAC) / owidth;
445
    s->v_incr = (iheight * POS_FRAC) / oheight;
446
    
447
    build_filter(&s->h_filters[0][0], (float)owidth / (float)iwidth);
448
    build_filter(&s->v_filters[0][0], (float)oheight / (float)iheight);
449

    
450
    return s;
451
 fail:
452
    free(s);
453
    return NULL;
454
}
455

    
456
void img_resample(ImgReSampleContext *s, 
457
                  AVPicture *output, AVPicture *input)
458
{
459
    int i, shift;
460

    
461
    for(i=0;i<3;i++) {
462
        shift = (i == 0) ? 0 : 1;
463
        component_resample(s, output->data[i], output->linesize[i], 
464
                           s->owidth >> shift, s->oheight >> shift,
465
                           input->data[i], input->linesize[i], 
466
                           s->iwidth >> shift, s->iheight >> shift);
467
    }
468
}
469

    
470
void img_resample_close(ImgReSampleContext *s)
471
{
472
    free(s->line_buf);
473
    free(s);
474
}
475

    
476
#ifdef TEST
477

    
478
void *av_mallocz(int size)
479
{
480
    void *ptr;
481
    ptr = malloc(size);
482
    memset(ptr, 0, size);
483
    return ptr;
484
}
485

    
486
/* input */
487
#define XSIZE 256
488
#define YSIZE 256
489
UINT8 img[XSIZE * YSIZE];
490

    
491
/* output */
492
#define XSIZE1 512
493
#define YSIZE1 512
494
UINT8 img1[XSIZE1 * YSIZE1];
495
UINT8 img2[XSIZE1 * YSIZE1];
496

    
497
void save_pgm(const char *filename, UINT8 *img, int xsize, int ysize)
498
{
499
    FILE *f;
500
    f=fopen(filename,"w");
501
    fprintf(f,"P5\n%d %d\n%d\n", xsize, ysize, 255);
502
    fwrite(img,1, xsize * ysize,f);
503
    fclose(f);
504
}
505

    
506
static void dump_filter(INT16 *filter)
507
{
508
    int i, ph;
509

    
510
    for(ph=0;ph<NB_PHASES;ph++) {
511
        printf("%2d: ", ph);
512
        for(i=0;i<NB_TAPS;i++) {
513
            printf(" %5.2f", filter[ph * NB_TAPS + i] / 256.0);
514
        }
515
        printf("\n");
516
    }
517
}
518

    
519
#ifdef HAVE_MMX
520
int mm_flags;
521
#endif
522

    
523
int main(int argc, char **argv)
524
{
525
    int x, y, v, i, xsize, ysize;
526
    ImgReSampleContext *s;
527
    float fact, factors[] = { 1/2.0, 3.0/4.0, 1.0, 4.0/3.0, 16.0/9.0, 2.0 };
528
    char buf[256];
529

    
530
    /* build test image */
531
    for(y=0;y<YSIZE;y++) {
532
        for(x=0;x<XSIZE;x++) {
533
            if (x < XSIZE/2 && y < YSIZE/2) {
534
                if (x < XSIZE/4 && y < YSIZE/4) {
535
                    if ((x % 10) <= 6 &&
536
                        (y % 10) <= 6)
537
                        v = 0xff;
538
                    else
539
                        v = 0x00;
540
                } else if (x < XSIZE/4) {
541
                    if (x & 1) 
542
                        v = 0xff;
543
                    else 
544
                        v = 0;
545
                } else if (y < XSIZE/4) {
546
                    if (y & 1) 
547
                        v = 0xff;
548
                    else 
549
                        v = 0;
550
                } else {
551
                    if (y < YSIZE*3/8) {
552
                        if ((y+x) & 1) 
553
                            v = 0xff;
554
                        else 
555
                            v = 0;
556
                    } else {
557
                        if (((x+3) % 4) <= 1 &&
558
                            ((y+3) % 4) <= 1)
559
                            v = 0xff;
560
                        else
561
                            v = 0x00;
562
                    }
563
                }
564
            } else if (x < XSIZE/2) {
565
                v = ((x - (XSIZE/2)) * 255) / (XSIZE/2);
566
            } else if (y < XSIZE/2) {
567
                v = ((y - (XSIZE/2)) * 255) / (XSIZE/2);
568
            } else {
569
                v = ((x + y - XSIZE) * 255) / XSIZE;
570
            }
571
            img[y * XSIZE + x] = v;
572
        }
573
    }
574
    save_pgm("/tmp/in.pgm", img, XSIZE, YSIZE);
575
    for(i=0;i<sizeof(factors)/sizeof(float);i++) {
576
        fact = factors[i];
577
        xsize = (int)(XSIZE * fact);
578
        ysize = (int)(YSIZE * fact);
579
        s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
580
        printf("Factor=%0.2f\n", fact);
581
        dump_filter(&s->h_filters[0][0]);
582
        component_resample(s, img1, xsize, xsize, ysize,
583
                           img, XSIZE, XSIZE, YSIZE);
584
        img_resample_close(s);
585

    
586
        sprintf(buf, "/tmp/out%d.pgm", i);
587
        save_pgm(buf, img1, xsize, ysize);
588
    }
589

    
590
    /* mmx test */
591
#ifdef HAVE_MMX
592
    printf("MMX test\n");
593
    fact = 0.72;
594
    xsize = (int)(XSIZE * fact);
595
    ysize = (int)(YSIZE * fact);
596
    mm_flags = MM_MMX;
597
    s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
598
    component_resample(s, img1, xsize, xsize, ysize,
599
                       img, XSIZE, XSIZE, YSIZE);
600

    
601
    mm_flags = 0;
602
    s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
603
    component_resample(s, img2, xsize, xsize, ysize,
604
                       img, XSIZE, XSIZE, YSIZE);
605
    if (memcmp(img1, img2, xsize * ysize) != 0) {
606
        fprintf(stderr, "mmx error\n");
607
        exit(1);
608
    }
609
    printf("MMX OK\n");
610
#endif
611
    return 0;
612
}
613

    
614
#endif