src/jpeg/jcsample.c

   1 /*
   2  * jcsample.c
   3  *
   4  * Copyright (C) 1991-1996, Thomas G. Lane.
   5  * This file is part of the Independent JPEG Group's software.
   6  * For conditions of distribution and use, see the accompanying README file.
   7  *
   8  * This file contains downsampling routines.
   9  *
  10  * Downsampling input data is counted in "row groups".  A row group
  11  * is defined to be max_v_samp_factor pixel rows of each component,
  12  * from which the downsampler produces v_samp_factor sample rows.
  13  * A single row group is processed in each call to the downsampler module.
  14  *
  15  * The downsampler is responsible for edge-expansion of its output data
  16  * to fill an integral number of DCT blocks horizontally.  The source buffer
  17  * may be modified if it is helpful for this purpose (the source buffer is
  18  * allocated wide enough to correspond to the desired output width).
  19  * The caller (the prep controller) is responsible for vertical padding.
  20  *
  21  * The downsampler may request "context rows" by setting need_context_rows
  22  * during startup.  In this case, the input arrays will contain at least
  23  * one row group's worth of pixels above and below the passed-in data;
  24  * the caller will create dummy rows at image top and bottom by replicating
  25  * the first or last real pixel row.
  26  *
  27  * An excellent reference for image resampling is
  28  *   Digital Image Warping, George Wolberg, 1990.
  29  *   Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
  30  *
  31  * The downsampling algorithm used here is a simple average of the source
  32  * pixels covered by the output pixel.  The hi-falutin sampling literature
  33  * refers to this as a "box filter".  In general the characteristics of a box
  34  * filter are not very good, but for the specific cases we normally use (1:1
  35  * and 2:1 ratios) the box is equivalent to a "triangle filter" which is not
  36  * nearly so bad.  If you intend to use other sampling ratios, you'd be well
  37  * advised to improve this code.
  38  *
  39  * A simple input-smoothing capability is provided.  This is mainly intended
  40  * for cleaning up color-dithered GIF input files (if you find it inadequate,
  41  * we suggest using an external filtering program such as pnmconvol).  When
  42  * enabled, each input pixel P is replaced by a weighted sum of itself and its
  43  * eight neighbors.  P's weight is 1-8*SF and each neighbor's weight is SF,
  44  * where SF = (smoothing_factor / 1024).
  45  * Currently, smoothing is only supported for 2h2v sampling factors.
  46  */
  47
  48 #define JPEG_INTERNALS
  49 #include "jinclude.h"
  50 #include "jpeglib.h"
  51
  52
  53 /* Pointer to routine to downsample a single component */
  54 typedef JMETHOD(void, downsample1_ptr,
  55                 (j_compress_ptr cinfo, jpeg_component_info * compptr,
  56                  JSAMPARRAY input_data, JSAMPARRAY output_data));
  57
  58 /* Private subobject */
  59
  60 typedef struct {
  61   struct jpeg_downsampler pub;  /* public fields */
  62
  63   /* Downsampling method pointers, one per component */
  64   downsample1_ptr methods[MAX_COMPONENTS];
  65 } my_downsampler;
  66
  67 typedef my_downsampler * my_downsample_ptr;
  68
  69
  70 /*
  71  * Initialize for a downsampling pass.
  72  */
  73
  74 METHODDEF(void)
  75 start_pass_downsample (j_compress_ptr cinfo)
  76 {
  77   /* no work for now */
  78 }
  79
  80
  81 /*
  82  * Expand a component horizontally from width input_cols to width output_cols,
  83  * by duplicating the rightmost samples.
  84  */
  85
  86 LOCAL(void)
  87 expand_right_edge (JSAMPARRAY image_data, int num_rows,
  88                    JDIMENSION input_cols, JDIMENSION output_cols)
  89 {
  90   register JSAMPROW ptr;
  91   register JSAMPLE pixval;
  92   register int count;
  93   int row;
  94   int numcols = (int) (output_cols - input_cols);
  95
  96   if (numcols > 0) {
  97     for (row = 0; row < num_rows; row++) {
  98       ptr = image_data[row] + input_cols;
  99       pixval = ptr[-1];         /* don't need GETJSAMPLE() here */
 100       for (count = numcols; count > 0; count--)
 101         *ptr++ = pixval;
 102     }
 103   }
 104 }
 105
 106
 107 /*
 108  * Do downsampling for a whole row group (all components).
 109  *
 110  * In this version we simply downsample each component independently.
 111  */
 112
 113 METHODDEF(void)
 114 sep_downsample (j_compress_ptr cinfo,
 115                 JSAMPIMAGE input_buf, JDIMENSION in_row_index,
 116                 JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)
 117 {
 118   my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;
 119   int ci;
 120   jpeg_component_info * compptr;
 121   JSAMPARRAY in_ptr, out_ptr;
 122
 123   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 124        ci++, compptr++) {
 125     in_ptr = input_buf[ci] + in_row_index;
 126     out_ptr = output_buf[ci] + (out_row_group_index * compptr->v_samp_factor);
 127     (*downsample->methods[ci]) (cinfo, compptr, in_ptr, out_ptr);
 128   }
 129 }
 130
 131
 132 /*
 133  * Downsample pixel values of a single component.
 134  * One row group is processed per call.
 135  * This version handles arbitrary integral sampling ratios, without smoothing.
 136  * Note that this version is not actually used for customary sampling ratios.
 137  */
 138
 139 METHODDEF(void)
 140 int_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
 141                 JSAMPARRAY input_data, JSAMPARRAY output_data)
 142 {
 143   int inrow, outrow, h_expand, v_expand, numpix, numpix2, h, v;
 144   JDIMENSION outcol, outcol_h;  /* outcol_h == outcol*h_expand */
 145   JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
 146   JSAMPROW inptr, outptr;
 147   JPEG_INT32 outvalue;
 148
 149   h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;
 150   v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;
 151   numpix = h_expand * v_expand;
 152   numpix2 = numpix/2;
 153
 154   /* Expand input data enough to let all the output samples be generated
 155    * by the standard loop.  Special-casing padded output would be more
 156    * efficient.
 157    */
 158   expand_right_edge(input_data, cinfo->max_v_samp_factor,
 159                     cinfo->image_width, output_cols * h_expand);
 160
 161   inrow = 0;
 162   for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
 163     outptr = output_data[outrow];
 164     for (outcol = 0, outcol_h = 0; outcol < output_cols;
 165          outcol++, outcol_h += h_expand) {
 166       outvalue = 0;
 167       for (v = 0; v < v_expand; v++) {
 168         inptr = input_data[inrow+v] + outcol_h;
 169         for (h = 0; h < h_expand; h++) {
 170           outvalue += (JPEG_INT32) GETJSAMPLE(*inptr++);
 171         }
 172       }
 173       *outptr++ = (JSAMPLE) ((outvalue + numpix2) / numpix);
 174     }
 175     inrow += v_expand;
 176   }
 177 }
 178
 179
 180 /*
 181  * Downsample pixel values of a single component.
 182  * This version handles the special case of a full-size component,
 183  * without smoothing.
 184  */
 185
 186 METHODDEF(void)
 187 fullsize_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
 188                      JSAMPARRAY input_data, JSAMPARRAY output_data)
 189 {
 190   /* Copy the data */
 191   jcopy_sample_rows(input_data, 0, output_data, 0,
 192                     cinfo->max_v_samp_factor, cinfo->image_width);
 193   /* Edge-expand */
 194   expand_right_edge(output_data, cinfo->max_v_samp_factor,
 195                     cinfo->image_width, compptr->width_in_blocks * DCTSIZE);
 196 }
 197
 198
 199 /*
 200  * Downsample pixel values of a single component.
 201  * This version handles the common case of 2:1 horizontal and 1:1 vertical,
 202  * without smoothing.
 203  *
 204  * A note about the "bias" calculations: when rounding fractional values to
 205  * integer, we do not want to always round 0.5 up to the next integer.
 206  * If we did that, we'd introduce a noticeable bias towards larger values.
 207  * Instead, this code is arranged so that 0.5 will be rounded up or down at
 208  * alternate pixel locations (a simple ordered dither pattern).
 209  */
 210
 211 METHODDEF(void)
 212 h2v1_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
 213                  JSAMPARRAY input_data, JSAMPARRAY output_data)
 214 {
 215   int outrow;
 216   JDIMENSION outcol;
 217   JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
 218   register JSAMPROW inptr, outptr;
 219   register int bias;
 220
 221   /* Expand input data enough to let all the output samples be generated
 222    * by the standard loop.  Special-casing padded output would be more
 223    * efficient.
 224    */
 225   expand_right_edge(input_data, cinfo->max_v_samp_factor,
 226                     cinfo->image_width, output_cols * 2);
 227
 228   for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
 229     outptr = output_data[outrow];
 230     inptr = input_data[outrow];
 231     bias = 0;                   /* bias = 0,1,0,1,... for successive samples */
 232     for (outcol = 0; outcol < output_cols; outcol++) {
 233       *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr) + GETJSAMPLE(inptr[1])
 234                               + bias) >> 1);
 235       bias ^= 1;                /* 0=>1, 1=>0 */
 236       inptr += 2;
 237     }
 238   }
 239 }
 240
 241
 242 /*
 243  * Downsample pixel values of a single component.
 244  * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
 245  * without smoothing.
 246  */
 247
 248 METHODDEF(void)
 249 h2v2_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
 250                  JSAMPARRAY input_data, JSAMPARRAY output_data)
 251 {
 252   int inrow, outrow;
 253   JDIMENSION outcol;
 254   JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
 255   register JSAMPROW inptr0, inptr1, outptr;
 256   register int bias;
 257
 258   /* Expand input data enough to let all the output samples be generated
 259    * by the standard loop.  Special-casing padded output would be more
 260    * efficient.
 261    */
 262   expand_right_edge(input_data, cinfo->max_v_samp_factor,
 263                     cinfo->image_width, output_cols * 2);
 264
 265   inrow = 0;
 266   for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
 267     outptr = output_data[outrow];
 268     inptr0 = input_data[inrow];
 269     inptr1 = input_data[inrow+1];
 270     bias = 1;                   /* bias = 1,2,1,2,... for successive samples */
 271     for (outcol = 0; outcol < output_cols; outcol++) {
 272       *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
 273                               GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1])
 274                               + bias) >> 2);
 275       bias ^= 3;                /* 1=>2, 2=>1 */
 276       inptr0 += 2; inptr1 += 2;
 277     }
 278     inrow += 2;
 279   }
 280 }
 281
 282
 283 #ifdef INPUT_SMOOTHING_SUPPORTED
 284
 285 /*
 286  * Downsample pixel values of a single component.
 287  * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
 288  * with smoothing.  One row of context is required.
 289  */
 290
 291 METHODDEF(void)
 292 h2v2_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
 293                         JSAMPARRAY input_data, JSAMPARRAY output_data)
 294 {
 295   int inrow, outrow;
 296   JDIMENSION colctr;
 297   JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
 298   register JSAMPROW inptr0, inptr1, above_ptr, below_ptr, outptr;
 299   JPEG_INT32 membersum, neighsum, memberscale, neighscale;
 300
 301   /* Expand input data enough to let all the output samples be generated
 302    * by the standard loop.  Special-casing padded output would be more
 303    * efficient.
 304    */
 305   expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
 306                     cinfo->image_width, output_cols * 2);
 307
 308   /* We don't bother to form the individual "smoothed" input pixel values;
 309    * we can directly compute the output which is the average of the four
 310    * smoothed values.  Each of the four member pixels contributes a fraction
 311    * (1-8*SF) to its own smoothed image and a fraction SF to each of the three
 312    * other smoothed pixels, therefore a total fraction (1-5*SF)/4 to the final
 313    * output.  The four corner-adjacent neighbor pixels contribute a fraction
 314    * SF to just one smoothed pixel, or SF/4 to the final output; while the
 315    * eight edge-adjacent neighbors contribute SF to each of two smoothed
 316    * pixels, or SF/2 overall.  In order to use integer arithmetic, these
 317    * factors are scaled by 2^16 = 65536.
 318    * Also recall that SF = smoothing_factor / 1024.
 319    */
 320
 321   memberscale = 16384 - cinfo->smoothing_factor * 80; /* scaled (1-5*SF)/4 */
 322   neighscale = cinfo->smoothing_factor * 16; /* scaled SF/4 */
 323
 324   inrow = 0;
 325   for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
 326     outptr = output_data[outrow];
 327     inptr0 = input_data[inrow];
 328     inptr1 = input_data[inrow+1];
 329     above_ptr = input_data[inrow-1];
 330     below_ptr = input_data[inrow+2];
 331
 332     /* Special case for first column: pretend column -1 is same as column 0 */
 333     membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
 334                 GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
 335     neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
 336                GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
 337                GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[2]) +
 338                GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[2]);
 339     neighsum += neighsum;
 340     neighsum += GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[2]) +
 341                 GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[2]);
 342     membersum = membersum * memberscale + neighsum * neighscale;
 343     *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
 344     inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
 345
 346     for (colctr = output_cols - 2; colctr > 0; colctr--) {
 347       /* sum of pixels directly mapped to this output element */
 348       membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
 349                   GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
 350       /* sum of edge-neighbor pixels */
 351       neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
 352                  GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
 353                  GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[2]) +
 354                  GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[2]);
 355       /* The edge-neighbors count twice as much as corner-neighbors */
 356       neighsum += neighsum;
 357       /* Add in the corner-neighbors */
 358       neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[2]) +
 359                   GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[2]);
 360       /* form final output scaled up by 2^16 */
 361       membersum = membersum * memberscale + neighsum * neighscale;
 362       /* round, descale and output it */
 363       *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
 364       inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
 365     }
 366
 367     /* Special case for last column */
 368     membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
 369                 GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
 370     neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
 371                GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
 372                GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[1]) +
 373                GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[1]);
 374     neighsum += neighsum;
 375     neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[1]) +
 376                 GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[1]);
 377     membersum = membersum * memberscale + neighsum * neighscale;
 378     *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
 379
 380     inrow += 2;
 381   }
 382 }
 383
 384
 385 /*
 386  * Downsample pixel values of a single component.
 387  * This version handles the special case of a full-size component,
 388  * with smoothing.  One row of context is required.
 389  */
 390
 391 METHODDEF(void)
 392 fullsize_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info *compptr,
 393                             JSAMPARRAY input_data, JSAMPARRAY output_data)
 394 {
 395   int outrow;
 396   JDIMENSION colctr;
 397   JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
 398   register JSAMPROW inptr, above_ptr, below_ptr, outptr;
 399   JPEG_INT32 membersum, neighsum, memberscale, neighscale;
 400   int colsum, lastcolsum, nextcolsum;
 401
 402   /* Expand input data enough to let all the output samples be generated
 403    * by the standard loop.  Special-casing padded output would be more
 404    * efficient.
 405    */
 406   expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
 407                     cinfo->image_width, output_cols);
 408
 409   /* Each of the eight neighbor pixels contributes a fraction SF to the
 410    * smoothed pixel, while the main pixel contributes (1-8*SF).  In order
 411    * to use integer arithmetic, these factors are multiplied by 2^16 = 65536.
 412    * Also recall that SF = smoothing_factor / 1024.
 413    */
 414
 415   memberscale = 65536L - cinfo->smoothing_factor * 512L; /* scaled 1-8*SF */
 416   neighscale = cinfo->smoothing_factor * 64; /* scaled SF */
 417
 418   for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
 419     outptr = output_data[outrow];
 420     inptr = input_data[outrow];
 421     above_ptr = input_data[outrow-1];
 422     below_ptr = input_data[outrow+1];
 423
 424     /* Special case for first column */
 425     colsum = GETJSAMPLE(*above_ptr++) + GETJSAMPLE(*below_ptr++) +
 426              GETJSAMPLE(*inptr);
 427     membersum = GETJSAMPLE(*inptr++);
 428     nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
 429                  GETJSAMPLE(*inptr);
 430     neighsum = colsum + (colsum - membersum) + nextcolsum;
 431     membersum = membersum * memberscale + neighsum * neighscale;
 432     *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
 433     lastcolsum = colsum; colsum = nextcolsum;
 434
 435     for (colctr = output_cols - 2; colctr > 0; colctr--) {
 436       membersum = GETJSAMPLE(*inptr++);
 437       above_ptr++; below_ptr++;
 438       nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
 439                    GETJSAMPLE(*inptr);
 440       neighsum = lastcolsum + (colsum - membersum) + nextcolsum;
 441       membersum = membersum * memberscale + neighsum * neighscale;
 442       *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
 443       lastcolsum = colsum; colsum = nextcolsum;
 444     }
 445
 446     /* Special case for last column */
 447     membersum = GETJSAMPLE(*inptr);
 448     neighsum = lastcolsum + (colsum - membersum) + colsum;
 449     membersum = membersum * memberscale + neighsum * neighscale;
 450     *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
 451
 452   }
 453 }
 454
 455 #endif /* INPUT_SMOOTHING_SUPPORTED */
 456
 457
 458 /*
 459  * Module initialization routine for downsampling.
 460  * Note that we must select a routine for each component.
 461  */
 462
 463 GLOBAL(void)
 464 jinit_downsampler (j_compress_ptr cinfo)
 465 {
 466   my_downsample_ptr downsample;
 467   int ci;
 468   jpeg_component_info * compptr;
 469   wxjpeg_boolean smoothok = TRUE;
 470
 471   downsample = (my_downsample_ptr)
 472     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 473                                 SIZEOF(my_downsampler));
 474   cinfo->downsample = (struct jpeg_downsampler *) downsample;
 475   downsample->pub.start_pass = start_pass_downsample;
 476   downsample->pub.downsample = sep_downsample;
 477   downsample->pub.need_context_rows = FALSE;
 478
 479   if (cinfo->CCIR601_sampling)
 480     ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
 481
 482   /* Verify we can handle the sampling factors, and set up method pointers */
 483   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 484        ci++, compptr++) {
 485     if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&
 486         compptr->v_samp_factor == cinfo->max_v_samp_factor) {
 487 #ifdef INPUT_SMOOTHING_SUPPORTED
 488       if (cinfo->smoothing_factor) {
 489         downsample->methods[ci] = fullsize_smooth_downsample;
 490         downsample->pub.need_context_rows = TRUE;
 491       } else
 492 #endif
 493         downsample->methods[ci] = fullsize_downsample;
 494     } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
 495                compptr->v_samp_factor == cinfo->max_v_samp_factor) {
 496       smoothok = FALSE;
 497       downsample->methods[ci] = h2v1_downsample;
 498     } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
 499                compptr->v_samp_factor * 2 == cinfo->max_v_samp_factor) {
 500 #ifdef INPUT_SMOOTHING_SUPPORTED
 501       if (cinfo->smoothing_factor) {
 502         downsample->methods[ci] = h2v2_smooth_downsample;
 503         downsample->pub.need_context_rows = TRUE;
 504       } else
 505 #endif
 506         downsample->methods[ci] = h2v2_downsample;
 507     } else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&
 508                (cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0) {
 509       smoothok = FALSE;
 510       downsample->methods[ci] = int_downsample;
 511     } else
 512       ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
 513   }
 514
 515 #ifdef INPUT_SMOOTHING_SUPPORTED
 516   if (cinfo->smoothing_factor && !smoothok)
 517     TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);
 518 #endif
 519 }