git.sesse.net Git - qscale/blob - qscale.c

   1 #include <stdio.h>
   2 #include <malloc.h>
   3 #include <math.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include "jpeglib.h"
   7
   8 #define CACHE_LINE_FACTOR 16
   9
  10 double sinc(double x)
  11 {
  12         static const double cutoff = 1.220703668e-4;  // sqrt(sqrt(eps))
  13
  14         if (abs(x) < cutoff) {
  15                 // For small |x|, use Taylor series instead
  16                 const double x2 = x * x;
  17                 const double x4 = x2 * x2;
  18
  19                 return 1.0 - x2 / 6.0 + x4 / 120.0;
  20         } else {
  21                 return sin(x) / x;
  22         }
  23 }
  24
  25 double lanczos_tap(double x)
  26 {
  27         if (x < -3.0 || x > 3.0)
  28                 return 0.0;
  29         if (x < 0.0)
  30                 return sinc(-x*M_PI) * sinc(-x*M_PI / 3.0);
  31         else
  32                 return sinc(x*M_PI) * sinc(x*M_PI / 3.0);
  33 }
  34
  35
  36 struct pix_desc {
  37         unsigned start, end;
  38         unsigned startcoeff;
  39 };
  40
  41 void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride)
  42 {
  43         struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
  44         int size_coeffs = 8;
  45         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
  46         int num_coeffs = 0;
  47         int x, y;
  48         double sf = (double)w / (double)nw;
  49         double support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
  50
  51         /* calculate the filter */
  52         for (x = 0; x < nw; ++x) {
  53                 int start = ceil(x * sf - support);
  54                 int end = floor(x * sf + support);
  55                 int sx;
  56                 double sum = 0.0;
  57
  58                 if (start < 0) {
  59                         start = 0;
  60                 }
  61                 if (end > w - 1) {
  62                         end = w - 1;
  63                 }
  64
  65                 // round up so we get a multiple of four for the SSE code
  66                 int num = (end - start + 1);
  67                 if (num % 4 != 0) {
  68                         // prefer aligning it if possible
  69                         if (start % 4 != 0 && start % 4 <= num % 4) {
  70                                 num += start % 4;
  71                                 start -= start % 4;
  72                         }
  73                         if (num % 4 != 0) {
  74                                 end += 4 - (num % 4);
  75                         }
  76                 }
  77
  78                 pd[x].start = start;
  79                 pd[x].end = end;
  80                 pd[x].startcoeff = num_coeffs;
  81
  82                 for (sx = start; sx <= end; ++sx) {
  83                         double nd = (w > nw) ? (sx/sf - x) : (sx - x*sf);
  84                         double f = lanczos_tap(nd);
  85                         if (num_coeffs == size_coeffs) {
  86                                 size_coeffs <<= 1;
  87                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
  88                         }
  89
  90                         coeffs[num_coeffs++] = f;
  91                         sum += f;
  92                 }
  93
  94                 for (sx = start; sx <= end; ++sx) {
  95                         coeffs[pd[x].startcoeff + sx - start] /= sum;
  96                 }
  97         }
  98
  99         for (y = 0; y < h; ++y) {
 100                 float *sptr = pix + y*sstride;
 101                 unsigned char *dptr = npix + y*dstride;
 102                 unsigned char ch;
 103                 for (x = 0; x < nw; ++x) {
 104                         int result;
 105                         float acc;
 106                         long tmp;
 107                         static const float low = 0.0, high = 255.0;
 108                         asm (
 109                                 "pxor %1, %1               \n"
 110                                 "xor %2, %2                \n"
 111                                 ".lbl2:                    \n"
 112                                 "movups (%4,%2),%%xmm1     \n"
 113                                 "movups (%3,%2),%%xmm2     \n"
 114                                 "mulps %%xmm2,%%xmm1       \n"
 115                                 "addps %%xmm1,%1           \n"
 116                                 "add $16,%2                \n"
 117                                 "dec %5                    \n"
 118                                 "jnz .lbl2                 \n"
 119                                 "haddps %1,%1              \n"
 120                                 "haddps %1,%1              \n"
 121                                 "maxss %6,%1               \n"
 122                                 "minss %7,%1               \n"
 123                                 "cvtss2si %1,%0            \n"
 124                                 : "=r" (result),
 125                                   "=&x" (acc),
 126                                   "=&r" (tmp)
 127                                 : "r" (&coeffs[pd[x].startcoeff]),
 128                                   "r" (&sptr[pd[x].start]),
 129                                   "r" ((pd[x].end - pd[x].start + 1)/4),
 130                                   "m" (low),
 131                                   "m" (high)
 132                                 : "xmm1", "xmm2"
 133                         );
 134
 135 #if 0
 136                         if (acc < 0.0)
 137                                 ch = 0;
 138                         else if (acc > 255.0)
 139                                 ch = 255;
 140                         else
 141                                 ch = (unsigned char)acc;
 142                         *dptr++ = ch;
 143 #endif
 144                         *dptr++ = (unsigned char)result;
 145                 }
 146                 ch = dptr[-1];
 147                 for ( ; x < dstride; ++x) {
 148                         *dptr++ = ch;
 149                 }
 150         }
 151 }
 152
 153 void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh, unsigned dstride)
 154 {
 155         struct pix_desc *pd = (struct pix_desc *)malloc(nh * sizeof(struct pix_desc));
 156         int size_coeffs = 8;
 157         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 158         int num_coeffs = 0;
 159         int x, y, sy;
 160         double sf = (double)h / (double)nh;
 161         double support = (h > nh) ? (3.0 * sf) : (3.0 / sf);
 162
 163         /* calculate the filter */
 164         for (y = 0; y < nh; ++y) {
 165                 int start = ceil(y * sf - support);
 166                 int end = floor(y * sf + support);
 167                 double sum = 0.0;
 168
 169                 if (start < 0) {
 170                         start = 0;
 171                 }
 172                 if (end > h - 1) {
 173                         end = h - 1;
 174                 }
 175
 176                 pd[y].start = start;
 177                 pd[y].end = end;
 178                 pd[y].startcoeff = num_coeffs;
 179
 180                 for (sy = start; sy <= end; ++sy) {
 181                         double nd = (h > nh) ? (sy/sf - y) : (sy - y*sf);
 182                         double f = lanczos_tap(nd);
 183                         if (num_coeffs == size_coeffs) {
 184                                 size_coeffs <<= 1;
 185                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 186                         }
 187
 188                         coeffs[num_coeffs++] = f;
 189                         sum += f;
 190                 }
 191
 192                 for (sy = start; sy <= end; ++sy) {
 193                         coeffs[pd[y].startcoeff + sy - start] /= sum;
 194                 }
 195         }
 196
 197 #if CACHE_LINE_FACTOR > 1
 198         for (x = 0; x < (w/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
 199                 unsigned char *sptr = pix + x;
 200                 float *dptr = npix + x;
 201                 for (y = 0; y < nh; ++y) {
 202 #if 0
 203                         int i;
 204                         float acc[CACHE_LINE_FACTOR];
 205                         for (i = 0; i < CACHE_LINE_FACTOR; ++i)
 206                                 acc[i] = 0.0;
 207                         float *cf = &coeffs[pd[y].startcoeff];
 208                         unsigned sy;
 209
 210                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 211                                 for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 212                                         acc[i] += sptr[sy * w + i] * *cf;
 213                                 }
 214                                 ++cf;
 215                         }
 216
 217                         for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 218                                 dptr[i] = acc[i];
 219                         }
 220 #else
 221                         /*
 222                          * xmm0 - xmm3: acc[0..15]
 223                          * xmm4: current filter coefficient
 224                          * xmm5, xmm6, xmm7: scratchpad
 225                          */
 226                         asm (
 227                                 /* clear */
 228                                 "pxor %%xmm0, %%xmm0          \n"
 229                                 "pxor %%xmm1, %%xmm1          \n"
 230                                 "pxor %%xmm2, %%xmm2          \n"
 231                                 "pxor %%xmm3, %%xmm3          \n"
 232
 233                                 /* main loop */
 234                                 ".lbl:                        \n"
 235
 236                                 /* a zero is useful during unpacking */
 237                                 "pxor %%xmm4, %%xmm4          \n"
 238
 239                                 /* fetch all 16 source bytes */
 240                                 "movups (%0), %%xmm5          \n"
 241                                 "prefetcht0 (%0,%3,4)         \n"
 242
 243                                 /* unpack into words (xmm5, xmm7) */
 244                                 "movaps %%xmm5, %%xmm7        \n"
 245                                 "punpcklbw %%xmm4, %%xmm5     \n"
 246                                 "punpckhbw %%xmm4, %%xmm7     \n"
 247
 248                                 /* unpack xmm5 into dwords (xmm5, xmm6) */
 249                                 "movaps %%xmm5, %%xmm6        \n"
 250                                 "punpcklwd %%xmm4, %%xmm5     \n"
 251                                 "punpckhwd %%xmm4, %%xmm6     \n"
 252
 253                                 /* convert xmm5, xmm6 to floats */
 254                                 "cvtdq2ps %%xmm5, %%xmm5      \n"
 255                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 256
 257                                 /* fetch the coefficient */
 258                                 "movss (%2), %%xmm4           \n"
 259                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 260
 261                                 /* do the muls for xmm5 and xmm6 */
 262                                 "mulps %%xmm4, %%xmm5         \n"
 263                                 "mulps %%xmm4, %%xmm6         \n"
 264                                 "addps %%xmm5, %%xmm0         \n"
 265                                 "addps %%xmm6, %%xmm1         \n"
 266
 267                                 /* get the zero back again */
 268                                 "pxor %%xmm4, %%xmm4          \n"
 269
 270                                 /* unpack xmm7 into dwords (xmm7, xmm6) */
 271                                 "movaps %%xmm7, %%xmm6        \n"
 272                                 "punpcklwd %%xmm4, %%xmm7     \n"
 273                                 "punpckhwd %%xmm4, %%xmm6     \n"
 274
 275                                 /* convert xmm7, xmm6 to floats */
 276                                 "cvtdq2ps %%xmm7, %%xmm7      \n"
 277                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 278
 279                                 /* fetch the coefficient */
 280                                 "movss (%2), %%xmm4           \n"
 281                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 282
 283                                 /* do the second set of muls */
 284                                 "mulps %%xmm4, %%xmm7         \n"
 285                                 "mulps %%xmm4, %%xmm6         \n"
 286                                 "addps %%xmm7, %%xmm2         \n"
 287                                 "addps %%xmm6, %%xmm3         \n"
 288
 289                                 /* move along, and loop */
 290                                 "add $4, %2                   \n"
 291                                 "add %3, %0                   \n"
 292                                 "dec %1                       \n"
 293                                 "jnz .lbl                     \n"
 294
 295                                 /* store the values */
 296                                 "movaps %%xmm0, (%4)          \n"
 297                                 "movaps %%xmm1, 16(%4)        \n"
 298                                 "movaps %%xmm2, 32(%4)        \n"
 299                                 "movaps %%xmm3, 48(%4)        \n"
 300                                 : :
 301                                 "r" (&sptr[pd[y].start * w]),        /* 0: srcptr base */
 302                                 "r" (pd[y].end - pd[y].start + 1),   /* 1: filter len */
 303                                 "r" (&coeffs[pd[y].startcoeff]),     /* 2: coeffs base */
 304                                 "r" ((long)w),                       /* 3: stride */
 305                                 "r" (dptr)                           /* 4: dstptr base */
 306                                 : "memory", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7"
 307                         );
 308 #endif
 309                         dptr += dstride;
 310                 }
 311         }
 312         for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
 313 #else
 314         for (x = 0; x < w; ++x) {
 315 #endif
 316                 unsigned char *sptr = pix + x;
 317                 float *dptr = npix + x;
 318                 for (y = 0; y < nh; ++y) {
 319                         float acc = 0.0;
 320                         float *cf = &coeffs[pd[y].startcoeff];
 321                         unsigned sy;
 322
 323                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 324                                 acc += sptr[sy * w] * *cf++;
 325                         }
 326
 327                         *dptr = acc;
 328                         dptr += dstride;
 329                 }
 330         }
 331 }
 332
 333 int main(int argc, char **argv)
 334 {
 335         unsigned nominal_w = atoi(argv[1]);
 336         unsigned nominal_h = atoi(argv[2]);
 337
 338         unsigned samp_h0 = 2, samp_v0 = 2;
 339         unsigned samp_h1 = 1, samp_v1 = 1;
 340         unsigned samp_h2 = 1, samp_v2 = 1;
 341         unsigned max_samp_h = 2, max_samp_v = 2;
 342
 343         unsigned nw0 = nominal_w * samp_h0 / max_samp_h, nh0 = nominal_h * samp_v0 / max_samp_v;
 344         unsigned nw1 = nominal_w * samp_h1 / max_samp_h, nh1 = nominal_h * samp_v1 / max_samp_v;
 345         unsigned nw2 = nominal_w * samp_h2 / max_samp_h, nh2 = nominal_h * samp_v2 / max_samp_v;
 346
 347         unsigned stride0 = (nw0 + DCTSIZE-1) & ~(DCTSIZE-1);
 348         unsigned stride1 = (nw1 + DCTSIZE-1) & ~(DCTSIZE-1);
 349         unsigned stride2 = (nw2 + DCTSIZE-1) & ~(DCTSIZE-1);
 350
 351         struct jpeg_decompress_struct dinfo;
 352         struct jpeg_error_mgr jerr;
 353         dinfo.err = jpeg_std_error(&jerr);
 354         jpeg_create_decompress(&dinfo);
 355         jpeg_stdio_src(&dinfo, stdin);
 356         jpeg_read_header(&dinfo, TRUE);
 357         dinfo.raw_data_out = TRUE;
 358         jpeg_start_decompress(&dinfo);
 359
 360         unsigned w0 = dinfo.image_width * dinfo.comp_info[0].h_samp_factor / dinfo.max_h_samp_factor;
 361         unsigned h0 = dinfo.image_height * dinfo.comp_info[0].v_samp_factor / dinfo.max_v_samp_factor;
 362
 363         unsigned w1 = dinfo.image_width * dinfo.comp_info[1].h_samp_factor / dinfo.max_h_samp_factor;
 364         unsigned h1 = dinfo.image_height * dinfo.comp_info[1].v_samp_factor / dinfo.max_v_samp_factor;
 365
 366         unsigned w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
 367         unsigned h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
 368
 369         fprintf(stderr, "Scaling using Lanczos filter:\n");
 370         fprintf(stderr, "  Y component: %ux%u -> %ux%u\n", dinfo.comp_info[0].width_in_blocks * DCTSIZE, dinfo.comp_info[0].height_in_blocks * DCTSIZE, nw0, nh0);
 371         fprintf(stderr, "  Cb component: %ux%u -> %ux%u\n", dinfo.comp_info[1].width_in_blocks * DCTSIZE, dinfo.comp_info[1].height_in_blocks * DCTSIZE, nw1, nh1);
 372         fprintf(stderr, "  Cr component: %ux%u -> %ux%u\n", dinfo.comp_info[2].width_in_blocks * DCTSIZE, dinfo.comp_info[2].height_in_blocks * DCTSIZE, nw2, nh2);
 373
 374         JSAMPLE *data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
 375         JSAMPLE *data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
 376         JSAMPLE *data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
 377         JSAMPLE *data_ny, *data_ncb, *data_ncr;
 378
 379         int total_lines = 0, blocks = 0;
 380         while (total_lines < dinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 381                 unsigned max_lines = dinfo.max_v_samp_factor * DCTSIZE;
 382
 383                 JSAMPROW y_row_ptrs[max_lines];
 384                 JSAMPROW cb_row_ptrs[max_lines];
 385                 JSAMPROW cr_row_ptrs[max_lines];
 386                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 387                 int i;
 388
 389                 for (i = 0; i < max_lines; ++i) {
 390                         y_row_ptrs[i]  = data_y  + (i+blocks*DCTSIZE*dinfo.comp_info[0].v_samp_factor) * dinfo.comp_info[0].width_in_blocks * DCTSIZE;
 391                         cb_row_ptrs[i] = data_cb + (i+blocks*DCTSIZE*dinfo.comp_info[1].v_samp_factor) * dinfo.comp_info[1].width_in_blocks * DCTSIZE;
 392                         cr_row_ptrs[i] = data_cr + (i+blocks*DCTSIZE*dinfo.comp_info[2].v_samp_factor) * dinfo.comp_info[2].width_in_blocks * DCTSIZE;
 393                 }
 394
 395                 total_lines += max_lines;
 396                 ++blocks;
 397
 398                 if (jpeg_read_raw_data(&dinfo, ptrs, max_lines) == 0)
 399                         break;
 400         }
 401
 402         {
 403                 float *npix = (float*)memalign(16, dinfo.comp_info[0].width_in_blocks * DCTSIZE * nh0 * sizeof(float));
 404                 vscale(data_y, npix, dinfo.comp_info[0].width_in_blocks * DCTSIZE, h0, nh0, dinfo.comp_info[0].width_in_blocks * DCTSIZE);
 405                 data_ny = (unsigned char *)malloc(nw0 * stride0);
 406                 hscale(npix, data_ny, w0, nh0, nw0, dinfo.comp_info[0].width_in_blocks * DCTSIZE, stride0);
 407                 free(npix);
 408         }
 409         {
 410                 float *npix = (float*)memalign(16, dinfo.comp_info[1].width_in_blocks * DCTSIZE * nh1 * sizeof(float));
 411                 vscale(data_cr, npix, dinfo.comp_info[1].width_in_blocks * DCTSIZE, h1, nh1, dinfo.comp_info[1].width_in_blocks * DCTSIZE);
 412                 data_ncr = (unsigned char *)malloc(nw1 * stride1);
 413                 hscale(npix, data_ncr, w1, nh1, nw1, dinfo.comp_info[1].width_in_blocks * DCTSIZE, stride1);
 414                 free(npix);
 415         }
 416         {
 417                 float *npix = (float*)memalign(16, dinfo.comp_info[2].width_in_blocks * DCTSIZE * nh2 * sizeof(float));
 418                 vscale(data_cb, npix, dinfo.comp_info[2].width_in_blocks * DCTSIZE, h2, nh2, dinfo.comp_info[2].width_in_blocks * DCTSIZE);
 419                 data_ncb = (unsigned char *)malloc(nw2 * stride2);
 420                 hscale(npix, data_ncb, w2, nh2, nw2, dinfo.comp_info[2].width_in_blocks * DCTSIZE, stride2);
 421                 free(npix);
 422         }
 423         jpeg_destroy_decompress(&dinfo);
 424
 425         struct jpeg_compress_struct cinfo;
 426         cinfo.err = jpeg_std_error(&jerr);
 427         jpeg_create_compress(&cinfo);
 428         jpeg_stdio_dest(&cinfo, stdout);
 429         cinfo.input_components = 3;
 430         jpeg_set_defaults(&cinfo);
 431         jpeg_set_quality(&cinfo, 85, FALSE);
 432         cinfo.image_width = nominal_w;
 433         cinfo.image_height = nominal_h;
 434         cinfo.raw_data_in = TRUE;
 435         jpeg_set_colorspace(&cinfo, JCS_YCbCr);
 436         cinfo.comp_info[0].h_samp_factor = samp_h0;
 437         cinfo.comp_info[0].v_samp_factor = samp_v0;
 438         cinfo.comp_info[1].h_samp_factor = samp_h1;
 439         cinfo.comp_info[1].v_samp_factor = samp_v1;
 440         cinfo.comp_info[2].h_samp_factor = samp_h2;
 441         cinfo.comp_info[2].v_samp_factor = samp_v2;
 442         jpeg_start_compress(&cinfo, TRUE);
 443
 444         total_lines = 0;
 445         blocks = 0;
 446         while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 447                 unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
 448
 449                 JSAMPROW y_row_ptrs[max_lines];
 450                 JSAMPROW cb_row_ptrs[max_lines];
 451                 JSAMPROW cr_row_ptrs[max_lines];
 452                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 453                 int i;
 454
 455                 for (i = 0; i < max_lines; ++i) {
 456                         // simple edge extension
 457                         int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
 458                         if (yline > nh0 - 1)
 459                                 yline = nh0 - 1;
 460
 461                         int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
 462                         if (cbline > nh1 - 1)
 463                                 cbline = nh1 - 1;
 464
 465                         int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
 466                         if (crline > nh2 - 1)
 467                                 crline = nh2 - 1;
 468
 469                         y_row_ptrs[i]  = data_ny  + yline * stride0;
 470                         cb_row_ptrs[i] = data_ncb + cbline * stride1;
 471                         cr_row_ptrs[i] = data_ncr + crline * stride2;
 472                 }
 473
 474                 total_lines += max_lines;
 475                 ++blocks;
 476
 477                 jpeg_write_raw_data(&cinfo, ptrs, max_lines);
 478         }
 479         jpeg_finish_compress(&cinfo);
 480         jpeg_destroy_compress(&cinfo);
 481
 482         return 0;
 483 }
 484