libavcodec/imgresample.c

   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
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * 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
  17  * 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>
  23 #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