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

   1 /*
   2  * qscale: Quick, high-quality JPEG-to-JPEG scaler.
   3  * Copyright (C) 2008 Steinar H. Gunderson <sgunderson@bigfoot.com>
   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, version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  17  */
  18
  19 #include <math.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <malloc.h>
  24
  25 #include "libqscale.h"
  26
  27 /* The number of pixels to process at a time when scaling vertically. */
  28 #define CACHE_LINE_FACTOR 16
  29
  30 /* Whether to use SSE for horizontal scaling or not (requires SSE3). */
  31 #define USE_HORIZONTAL_SSE 1
  32
  33 /* Whether to use SSE for vertical scaling or not (requires only SSE1). */
  34 #define USE_VERTICAL_SSE 1
  35
  36 #if USE_VERTICAL_SSE
  37 #undef CACHE_LINE_FACTOR
  38 #define CACHE_LINE_FACTOR 16
  39 #endif
  40
  41 #ifndef M_PI
  42 #define M_PI 3.14159265358979323846264
  43 #endif
  44
  45 qscale_img *qscale_load_jpeg(const char *filename)
  46 {
  47         FILE *file = fopen(filename, "rb");
  48         qscale_img *img;
  49         if (file == NULL) {
  50                 return NULL;
  51         }
  52
  53         img = qscale_load_jpeg_from_stdio(file);
  54
  55         fclose(file);
  56         return img;
  57 }
  58
  59 qscale_img *qscale_load_jpeg_from_stdio(FILE *file)
  60 {
  61         qscale_img *img = (qscale_img *)malloc(sizeof(qscale_img));
  62         if (img == NULL) {
  63                 return NULL;
  64         }
  65
  66         img->data_y = img->data_cb = img->data_cr = NULL;
  67
  68         /* FIXME: Better error handling here (ie., return NULL). */
  69         struct jpeg_decompress_struct dinfo;
  70         struct jpeg_error_mgr jerr;
  71         dinfo.err = jpeg_std_error(&jerr);
  72         jpeg_create_decompress(&dinfo);
  73         jpeg_stdio_src(&dinfo, file);
  74         jpeg_read_header(&dinfo, TRUE);
  75         dinfo.raw_data_out = TRUE;
  76         jpeg_start_decompress(&dinfo);
  77
  78         /* We do not handle anything but YCbCr images (yet?). */
  79         if (dinfo.num_components != 3) {
  80                 qscale_destroy(img);
  81                 return NULL;
  82         }
  83
  84         img->width = dinfo.image_width;
  85         img->height = dinfo.image_height;
  86
  87         img->w0 = dinfo.image_width * dinfo.comp_info[0].h_samp_factor / dinfo.max_h_samp_factor;
  88         img->h0 = dinfo.image_height * dinfo.comp_info[0].v_samp_factor / dinfo.max_v_samp_factor;
  89
  90         img->w1 = dinfo.image_width * dinfo.comp_info[1].h_samp_factor / dinfo.max_h_samp_factor;
  91         img->h1 = dinfo.image_height * dinfo.comp_info[1].v_samp_factor / dinfo.max_v_samp_factor;
  92
  93         img->w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
  94         img->h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
  95
  96         img->samp_h0 = dinfo.comp_info[0].h_samp_factor;
  97         img->samp_v0 = dinfo.comp_info[0].v_samp_factor;
  98
  99         img->samp_h1 = dinfo.comp_info[1].h_samp_factor;
 100         img->samp_v1 = dinfo.comp_info[1].v_samp_factor;
 101
 102         img->samp_h2 = dinfo.comp_info[2].h_samp_factor;
 103         img->samp_v2 = dinfo.comp_info[2].v_samp_factor;
 104
 105         img->data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
 106         img->data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
 107         img->data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
 108
 109         if (img->data_y == NULL || img->data_cb == NULL || img->data_cr == NULL) {
 110                 qscale_destroy(img);
 111                 return NULL;
 112         }
 113
 114         int total_lines = 0, blocks = 0;
 115         while (total_lines < dinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 116                 unsigned max_lines = dinfo.max_v_samp_factor * DCTSIZE;
 117
 118                 JSAMPROW y_row_ptrs[max_lines];
 119                 JSAMPROW cb_row_ptrs[max_lines];
 120                 JSAMPROW cr_row_ptrs[max_lines];
 121                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 122
 123                 int i;
 124                 for (i = 0; i < max_lines; ++i) {
 125                         y_row_ptrs[i]  = img->data_y  + (i+blocks*DCTSIZE*dinfo.comp_info[0].v_samp_factor) * dinfo.comp_info[0].width_in_blocks * DCTSIZE;
 126                         cb_row_ptrs[i] = img->data_cb + (i+blocks*DCTSIZE*dinfo.comp_info[1].v_samp_factor) * dinfo.comp_info[1].width_in_blocks * DCTSIZE;
 127                         cr_row_ptrs[i] = img->data_cr + (i+blocks*DCTSIZE*dinfo.comp_info[2].v_samp_factor) * dinfo.comp_info[2].width_in_blocks * DCTSIZE;
 128                 }
 129
 130                 total_lines += max_lines;
 131                 ++blocks;
 132
 133                 if (jpeg_read_raw_data(&dinfo, ptrs, max_lines) == 0)
 134                         break;
 135         }
 136
 137         jpeg_destroy_decompress(&dinfo);
 138         return img;
 139 }
 140
 141 void qscale_destroy(qscale_img *img)
 142 {
 143         free(img->data_y);
 144         free(img->data_cb);
 145         free(img->data_cr);
 146         free(img);
 147 }
 148
 149
 150 static double sinc(double x)
 151 {
 152         static const double cutoff = 1.220703668e-4;  /* sqrt(sqrt(eps)) */
 153
 154         if (abs(x) < cutoff) {
 155                 /* For small |x|, use Taylor series instead */
 156                 const double x2 = x * x;
 157                 const double x4 = x2 * x2;
 158
 159                 return 1.0 - x2 / 6.0 + x4 / 120.0;
 160         } else {
 161                 return sin(x) / x;
 162         }
 163 }
 164
 165 static double lanczos_tap(double x)
 166 {
 167         if (x < -3.0 || x > 3.0)
 168                 return 0.0;
 169         if (x < 0.0)
 170                 return sinc(-x*M_PI) * sinc(-x*M_PI / 3.0);
 171         else
 172                 return sinc(x*M_PI) * sinc(x*M_PI / 3.0);
 173 }
 174
 175 struct pix_desc {
 176         unsigned start, end;
 177         unsigned startcoeff;
 178 };
 179
 180 static void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride)
 181 {
 182         struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
 183         int size_coeffs = 8;
 184         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 185         int num_coeffs = 0;
 186         int x, y;
 187         double sf = (double)w / (double)nw;
 188         double support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
 189
 190         /* calculate the filter */
 191         for (x = 0; x < nw; ++x) {
 192                 int start = ceil(x * sf - support);
 193                 int end = floor(x * sf + support);
 194                 int sx;
 195                 double sum = 0.0;
 196
 197                 if (start < 0) {
 198                         start = 0;
 199                 }
 200                 if (end > w - 1) {
 201                         end = w - 1;
 202                 }
 203
 204 #if USE_HORIZONTAL_SSE
 205                 /* round up so we get a multiple of four for the SSE code */
 206                 int num = (end - start + 1);
 207                 if (num % 4 != 0) {
 208                         /* prefer aligning it if possible */
 209                         if (start % 4 != 0 && start % 4 <= num % 4) {
 210                                 num += start % 4;
 211                                 start -= start % 4;
 212                         }
 213                         if (num % 4 != 0) {
 214                                 end += 4 - (num % 4);
 215                         }
 216                 }
 217 #endif
 218
 219                 pd[x].start = start;
 220                 pd[x].end = end;
 221                 pd[x].startcoeff = num_coeffs;
 222
 223                 for (sx = start; sx <= end; ++sx) {
 224                         double nd = (w > nw) ? (sx/sf - x) : (sx - x*sf);
 225                         double f = lanczos_tap(nd);
 226                         if (num_coeffs == size_coeffs) {
 227                                 size_coeffs <<= 1;
 228                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 229                         }
 230
 231                         coeffs[num_coeffs++] = f;
 232                         sum += f;
 233                 }
 234
 235                 for (sx = start; sx <= end; ++sx) {
 236                         coeffs[pd[x].startcoeff + sx - start] /= sum;
 237                 }
 238         }
 239
 240         for (y = 0; y < h; ++y) {
 241                 float *sptr = pix + y*sstride;
 242                 unsigned char *dptr = npix + y*dstride;
 243                 unsigned char ch;
 244                 for (x = 0; x < nw; ++x) {
 245 #if USE_HORIZONTAL_SSE
 246                         int result;
 247                         float acc;
 248                         long tmp;
 249                         static const float low = 0.0, high = 255.0;
 250                         __asm__ (
 251                                 "pxor %1, %1               \n"
 252                                 "xor %2, %2                \n"
 253                                 "0:                        \n"
 254                                 "movups (%4,%2),%%xmm1     \n"
 255                                 "movups (%3,%2),%%xmm2     \n"
 256                                 "mulps %%xmm2,%%xmm1       \n"
 257                                 "addps %%xmm1,%1           \n"
 258                                 "add $16,%2                \n"
 259                                 "dec %5                    \n"
 260                                 "jnz 0b                    \n"
 261                                 "haddps %1,%1              \n"
 262                                 "haddps %1,%1              \n"
 263                                 "maxss %6,%1               \n"
 264                                 "minss %7,%1               \n"
 265                                 "cvtss2si %1,%0            \n"
 266                                 : "=r" (result),
 267                                   "=&x" (acc),
 268                                   "=&r" (tmp)
 269                                 : "r" (&coeffs[pd[x].startcoeff]),
 270                                   "r" (&sptr[pd[x].start]),
 271                                   "r" ((pd[x].end - pd[x].start + 1)/4),
 272                                   "m" (low),
 273                                   "m" (high)
 274                                 : "memory", "xmm1", "xmm2"
 275                         );
 276
 277                         *dptr++ = (unsigned char)result;
 278 #else
 279                         float acc = 0.0;
 280                         float *cf = &coeffs[pd[x].startcoeff];
 281                         unsigned sx;
 282
 283                         for (sx = pd[x].start; sx <= pd[x].end; ++sx) {
 284                                 acc += sptr[sx] * *cf++;
 285                         }
 286
 287                         if (acc < 0.0)
 288                                 ch = 0;
 289                         else if (acc > 255.0)
 290                                 ch = 255;
 291                         else
 292                                 ch = (unsigned char)acc;
 293                         *dptr++ = ch;
 294 #endif
 295                 }
 296                 ch = dptr[-1];
 297                 for ( ; x < dstride; ++x) {
 298                         *dptr++ = ch;
 299                 }
 300         }
 301 }
 302
 303 static void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh, unsigned dstride)
 304 {
 305         struct pix_desc *pd = (struct pix_desc *)malloc(nh * sizeof(struct pix_desc));
 306         int size_coeffs = 8;
 307         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 308         int num_coeffs = 0;
 309         int x, y, sy;
 310         double sf = (double)h / (double)nh;
 311         double support = (h > nh) ? (3.0 * sf) : (3.0 / sf);
 312
 313         /* calculate the filter */
 314         for (y = 0; y < nh; ++y) {
 315                 int start = ceil(y * sf - support);
 316                 int end = floor(y * sf + support);
 317                 double sum = 0.0;
 318
 319                 if (start < 0) {
 320                         start = 0;
 321                 }
 322                 if (end > h - 1) {
 323                         end = h - 1;
 324                 }
 325
 326                 pd[y].start = start;
 327                 pd[y].end = end;
 328                 pd[y].startcoeff = num_coeffs;
 329
 330                 for (sy = start; sy <= end; ++sy) {
 331                         double nd = (h > nh) ? (sy/sf - y) : (sy - y*sf);
 332                         double f = lanczos_tap(nd);
 333                         if (num_coeffs == size_coeffs) {
 334                                 size_coeffs <<= 1;
 335                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 336                         }
 337
 338                         coeffs[num_coeffs++] = f;
 339                         sum += f;
 340                 }
 341
 342                 for (sy = start; sy <= end; ++sy) {
 343                         coeffs[pd[y].startcoeff + sy - start] /= sum;
 344                 }
 345         }
 346
 347 #if CACHE_LINE_FACTOR > 1
 348         for (x = 0; x < (w/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
 349                 unsigned char *sptr = pix + x;
 350                 float *dptr = npix + x;
 351                 for (y = 0; y < nh; ++y) {
 352 #if USE_VERTICAL_SSE
 353                         /*
 354                          * xmm0 - xmm3: acc[0..15]
 355                          * xmm4: current filter coefficient
 356                          * xmm5, xmm6, xmm7: scratchpad
 357                          */
 358                         __asm__ (
 359                                 /* clear */
 360                                 "pxor %%xmm0, %%xmm0          \n"
 361                                 "pxor %%xmm1, %%xmm1          \n"
 362                                 "pxor %%xmm2, %%xmm2          \n"
 363                                 "pxor %%xmm3, %%xmm3          \n"
 364
 365                                 /* main loop */
 366                                 "0:                           \n"
 367
 368                                 /* a zero is useful during unpacking */
 369                                 "pxor %%xmm4, %%xmm4          \n"
 370
 371                                 /* fetch all 16 source bytes */
 372                                 "movups (%0), %%xmm5          \n"
 373                                 "prefetcht0 (%0,%3,4)         \n"
 374
 375                                 /* unpack into words (xmm5, xmm7) */
 376                                 "movaps %%xmm5, %%xmm7        \n"
 377                                 "punpcklbw %%xmm4, %%xmm5     \n"
 378                                 "punpckhbw %%xmm4, %%xmm7     \n"
 379
 380                                 /* unpack xmm5 into dwords (xmm5, xmm6) */
 381                                 "movaps %%xmm5, %%xmm6        \n"
 382                                 "punpcklwd %%xmm4, %%xmm5     \n"
 383                                 "punpckhwd %%xmm4, %%xmm6     \n"
 384
 385                                 /* convert xmm5, xmm6 to floats */
 386                                 "cvtdq2ps %%xmm5, %%xmm5      \n"
 387                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 388
 389                                 /* fetch the coefficient */
 390                                 "movss (%2), %%xmm4           \n"
 391                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 392
 393                                 /* do the muls for xmm5 and xmm6 */
 394                                 "mulps %%xmm4, %%xmm5         \n"
 395                                 "mulps %%xmm4, %%xmm6         \n"
 396                                 "addps %%xmm5, %%xmm0         \n"
 397                                 "addps %%xmm6, %%xmm1         \n"
 398
 399                                 /* get the zero back again */
 400                                 "pxor %%xmm4, %%xmm4          \n"
 401
 402                                 /* unpack xmm7 into dwords (xmm7, xmm6) */
 403                                 "movaps %%xmm7, %%xmm6        \n"
 404                                 "punpcklwd %%xmm4, %%xmm7     \n"
 405                                 "punpckhwd %%xmm4, %%xmm6     \n"
 406
 407                                 /* convert xmm7, xmm6 to floats */
 408                                 "cvtdq2ps %%xmm7, %%xmm7      \n"
 409                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 410
 411                                 /* fetch the coefficient */
 412                                 "movss (%2), %%xmm4           \n"
 413                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 414
 415                                 /* do the second set of muls */
 416                                 "mulps %%xmm4, %%xmm7         \n"
 417                                 "mulps %%xmm4, %%xmm6         \n"
 418                                 "addps %%xmm7, %%xmm2         \n"
 419                                 "addps %%xmm6, %%xmm3         \n"
 420
 421                                 /* move along, and loop */
 422                                 "add $4, %2                   \n"
 423                                 "add %3, %0                   \n"
 424                                 "dec %1                       \n"
 425                                 "jnz 0b                       \n"
 426
 427                                 /* store the values */
 428                                 "movaps %%xmm0, (%4)          \n"
 429                                 "movaps %%xmm1, 16(%4)        \n"
 430                                 "movaps %%xmm2, 32(%4)        \n"
 431                                 "movaps %%xmm3, 48(%4)        \n"
 432                                 : :
 433                                 "r" (&sptr[pd[y].start * w]),        /* 0: srcptr base */
 434                                 "r" (pd[y].end - pd[y].start + 1),   /* 1: filter len */
 435                                 "r" (&coeffs[pd[y].startcoeff]),     /* 2: coeffs base */
 436                                 "r" ((long)w),                       /* 3: stride */
 437                                 "r" (dptr)                           /* 4: dstptr base */
 438                                 : "memory", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7"
 439                         );
 440 #else
 441                         int i;
 442                         float acc[CACHE_LINE_FACTOR];
 443                         for (i = 0; i < CACHE_LINE_FACTOR; ++i)
 444                                 acc[i] = 0.0;
 445                         float *cf = &coeffs[pd[y].startcoeff];
 446                         unsigned sy;
 447
 448                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 449                                 for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 450                                         acc[i] += sptr[sy * w + i] * *cf;
 451                                 }
 452                                 ++cf;
 453                         }
 454
 455                         for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 456                                 dptr[i] = acc[i];
 457                         }
 458 #endif
 459                         dptr += dstride;
 460                 }
 461         }
 462         for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
 463 #else
 464         for (x = 0; x < w; ++x) {
 465 #endif
 466                 unsigned char *sptr = pix + x;
 467                 float *dptr = npix + x;
 468                 for (y = 0; y < nh; ++y) {
 469                         float acc = 0.0;
 470                         float *cf = &coeffs[pd[y].startcoeff];
 471                         unsigned sy;
 472
 473                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 474                                 acc += sptr[sy * w] * *cf++;
 475                         }
 476
 477                         *dptr = acc;
 478                         dptr += dstride;
 479                 }
 480         }
 481 }
 482
 483 qscale_img *qscale_clone(const qscale_img *img)
 484 {
 485         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 486         if (dst == NULL) {
 487                 return NULL;
 488         }
 489
 490         *dst = *img;
 491
 492         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 493         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 494         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 495
 496         /* FIXME: handle out-of-memory gracefully */
 497         {
 498                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 499                 memcpy(dst->data_y, img->data_y, dst->h0 * dstride0);
 500         }
 501         {
 502                 dst->data_cb = (unsigned char *)malloc(dst->h1 * dstride1);
 503                 memcpy(dst->data_cb, img->data_cb, dst->h0 * dstride0);
 504         }
 505         {
 506                 dst->data_cr = (unsigned char *)malloc(dst->h1 * dstride1);
 507                 memcpy(dst->data_cr, img->data_cr, dst->h0 * dstride0);
 508         }
 509
 510         return dst;
 511 }
 512
 513 qscale_img *qscale_scale(qscale_img *src, unsigned width, unsigned height, unsigned samp_h0, unsigned samp_v0, unsigned samp_h1, unsigned samp_v1, unsigned samp_h2, unsigned samp_v2, enum qscale_scaling_filter scaling_filter)
 514 {
 515         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 516         if (dst == NULL) {
 517                 return NULL;
 518         }
 519
 520         dst->width = width;
 521         dst->height = height;
 522
 523         unsigned max_samp_h, max_samp_v;
 524         max_samp_h = samp_h0;
 525         if (samp_h1 > max_samp_h)
 526                 max_samp_h = samp_h1;
 527         if (samp_h2 > max_samp_h)
 528                 max_samp_h = samp_h2;
 529
 530         max_samp_v = samp_v0;
 531         if (samp_v1 > max_samp_v)
 532                 max_samp_v = samp_v1;
 533         if (samp_v2 > max_samp_v)
 534                 max_samp_v = samp_v2;
 535
 536         dst->w0 = width * samp_h0 / max_samp_h;
 537         dst->h0 = height * samp_v0 / max_samp_v;
 538
 539         dst->w1 = width * samp_h1 / max_samp_h;
 540         dst->h1 = height * samp_v1 / max_samp_v;
 541
 542         dst->w2 = width * samp_h2 / max_samp_h;
 543         dst->h2 = height * samp_v2 / max_samp_v;
 544
 545         dst->samp_h0 = samp_h0;
 546         dst->samp_v0 = samp_v0;
 547
 548         dst->samp_h1 = samp_h1;
 549         dst->samp_v1 = samp_v1;
 550
 551         dst->samp_h2 = samp_h2;
 552         dst->samp_v2 = samp_v2;
 553
 554         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 555         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 556         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 557
 558         unsigned sstride0 = (src->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 559         unsigned sstride1 = (src->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 560         unsigned sstride2 = (src->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 561
 562         /* FIXME: handle out-of-memory gracefully */
 563         {
 564                 float *npix = (float*)memalign(16, sstride0 * dst->h0 * sizeof(float));
 565                 vscale(src->data_y, npix, sstride0, src->h0, dst->h0, sstride0);
 566                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 567                 hscale(npix, dst->data_y, src->w0, dst->h0, dst->w0, sstride0, dstride0);
 568                 free(npix);
 569         }
 570         {
 571                 float *npix = (float*)memalign(16, sstride1 * dst->h1 * sizeof(float));
 572                 vscale(src->data_cr, npix, sstride1, src->h1, dst->h1, sstride1);
 573                 dst->data_cr = (unsigned char *)malloc(dst->h1 * dstride1);
 574                 hscale(npix, dst->data_cr, src->w1, dst->h1, dst->w1, sstride1, dstride1);
 575                 free(npix);
 576         }
 577         {
 578                 float *npix = (float*)memalign(16, sstride2 * dst->h2 * sizeof(float));
 579                 vscale(src->data_cb, npix, sstride2, src->h2, dst->h2, sstride2);
 580                 dst->data_cb = (unsigned char *)malloc(dst->h2 * dstride2);
 581                 hscale(npix, dst->data_cb, src->w2, dst->h2, dst->w2, sstride2, dstride2);
 582                 free(npix);
 583         }
 584
 585         return dst;
 586 }
 587
 588 int qscale_save_jpeg(const qscale_img *img, const char *filename, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 589 {
 590         FILE *file = fopen(filename, "wb");
 591         if (file == NULL) {
 592                 return -1;
 593         }
 594
 595         int err = qscale_save_jpeg_to_stdio(img, file, jpeg_quality, jpeg_mode);
 596
 597         fclose(file);
 598         return err;
 599 }
 600
 601 int qscale_save_jpeg_to_stdio(const qscale_img *img, FILE *file, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 602 {
 603         struct jpeg_compress_struct cinfo;
 604         struct jpeg_error_mgr jerr;
 605         cinfo.err = jpeg_std_error(&jerr);
 606         jpeg_create_compress(&cinfo);
 607         jpeg_stdio_dest(&cinfo, file);
 608         cinfo.input_components = 3;
 609         jpeg_set_defaults(&cinfo);
 610         jpeg_set_quality(&cinfo, jpeg_quality, FALSE);
 611
 612         if (jpeg_mode == PROGRESSIVE) {
 613                 jpeg_simple_progression(&cinfo);
 614         }
 615
 616         cinfo.image_width = img->width;
 617         cinfo.image_height = img->height;
 618         cinfo.raw_data_in = TRUE;
 619         jpeg_set_colorspace(&cinfo, JCS_YCbCr);
 620         cinfo.comp_info[0].h_samp_factor = img->samp_h0;
 621         cinfo.comp_info[0].v_samp_factor = img->samp_v0;
 622         cinfo.comp_info[1].h_samp_factor = img->samp_h1;
 623         cinfo.comp_info[1].v_samp_factor = img->samp_v1;
 624         cinfo.comp_info[2].h_samp_factor = img->samp_h2;
 625         cinfo.comp_info[2].v_samp_factor = img->samp_v2;
 626         jpeg_start_compress(&cinfo, TRUE);
 627
 628         unsigned dstride0 = (img->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 629         unsigned dstride1 = (img->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 630         unsigned dstride2 = (img->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 631
 632         int total_lines = 0;
 633         int blocks = 0;
 634         while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 635                 unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
 636
 637                 JSAMPROW y_row_ptrs[max_lines];
 638                 JSAMPROW cb_row_ptrs[max_lines];
 639                 JSAMPROW cr_row_ptrs[max_lines];
 640                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 641                 int i;
 642
 643                 for (i = 0; i < max_lines; ++i) {
 644                         /* simple edge extension */
 645                         int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
 646                         if (yline > img->h0 - 1)
 647                                 yline = img->h0 - 1;
 648
 649                         int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
 650                         if (cbline > img->h1 - 1)
 651                                 cbline = img->h1 - 1;
 652
 653                         int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
 654                         if (crline > img->h2 - 1)
 655                                 crline = img->h2 - 1;
 656
 657                         y_row_ptrs[i]  = img->data_y  + yline * dstride0;
 658                         cb_row_ptrs[i] = img->data_cb + cbline * dstride1;
 659                         cr_row_ptrs[i] = img->data_cr + crline * dstride2;
 660                 }
 661
 662                 total_lines += max_lines;
 663                 ++blocks;
 664
 665                 jpeg_write_raw_data(&cinfo, ptrs, max_lines);
 666         }
 667         jpeg_finish_compress(&cinfo);
 668         jpeg_destroy_compress(&cinfo);
 669
 670         return 0;
 671 }