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