1 /*
2 * jcmaster.c
3 *
4 * Copyright (C) 1991-1995, 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 master control logic for the JPEG compressor.
9 * These routines are concerned with parameter validation, initial setup,
10 * and inter-pass control (determining the number of passes and the work
11 * to be done in each pass).
12 */
13
14 #define JPEG_INTERNALS
15 #include "jinclude.h"
16 #include "jpeglib.h"
17
18
19 /* Private state */
20
21 typedef enum {
22 main_pass, /* input data, also do first output step */
23 huff_opt_pass, /* Huffman code optimization pass */
24 output_pass /* data output pass */
25 } c_pass_type;
26
27 typedef struct {
28 struct jpeg_comp_master pub; /* public fields */
29
30 c_pass_type pass_type; /* the type of the current pass */
31
32 int pass_number; /* # of passes completed */
33 int total_passes; /* total # of passes needed */
34
35 int scan_number; /* current index in scan_info[] */
36 } my_comp_master;
37
38 typedef my_comp_master * my_master_ptr;
39
40
41 /*
42 * Support routines that do various essential calculations.
43 */
44
45 LOCAL void
initial_setup(j_compress_ptr cinfo)46 initial_setup (j_compress_ptr cinfo)
47 /* Do computations that are needed before master selection phase */
48 {
49 int ci;
50 jpeg_component_info *compptr;
51 long samplesperrow;
52 JDIMENSION jd_samplesperrow;
53
54 /* Sanity check on image dimensions */
55 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
56 || cinfo->num_components <= 0 || cinfo->input_components <= 0)
57 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
58
59 /* Make sure image isn't bigger than I can handle */
60 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
61 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
62 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
63
64 /* Width of an input scanline must be representable as JDIMENSION. */
65 samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
66 jd_samplesperrow = (JDIMENSION) samplesperrow;
67 if ((long) jd_samplesperrow != samplesperrow)
68 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
69
70 /* For now, precision must match compiled-in value... */
71 if (cinfo->data_precision != BITS_IN_JSAMPLE)
72 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
73
74 /* Check that number of components won't exceed internal array sizes */
75 if (cinfo->num_components > MAX_COMPONENTS)
76 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
77 MAX_COMPONENTS);
78
79 /* Compute maximum sampling factors; check factor validity */
80 cinfo->max_h_samp_factor = 1;
81 cinfo->max_v_samp_factor = 1;
82 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
83 ci++, compptr++) {
84 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
85 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
86 ERREXIT(cinfo, JERR_BAD_SAMPLING);
87 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
88 compptr->h_samp_factor);
89 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
90 compptr->v_samp_factor);
91 }
92
93 /* Compute dimensions of components */
94 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
95 ci++, compptr++) {
96 /* Fill in the correct component_index value; don't rely on application */
97 compptr->component_index = ci;
98 /* For compression, we never do DCT scaling. */
99 compptr->DCT_scaled_size = DCTSIZE;
100 /* Size in DCT blocks */
101 compptr->width_in_blocks = (JDIMENSION)
102 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
103 (long) (cinfo->max_h_samp_factor * DCTSIZE));
104 compptr->height_in_blocks = (JDIMENSION)
105 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
106 (long) (cinfo->max_v_samp_factor * DCTSIZE));
107 /* Size in samples */
108 compptr->downsampled_width = (JDIMENSION)
109 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
110 (long) cinfo->max_h_samp_factor);
111 compptr->downsampled_height = (JDIMENSION)
112 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
113 (long) cinfo->max_v_samp_factor);
114 /* Mark component needed (this flag isn't actually used for compression) */
115 compptr->component_needed = TRUE;
116 }
117
118 /* Compute number of fully interleaved MCU rows (number of times that
119 * main controller will call coefficient controller).
120 */
121 cinfo->total_iMCU_rows = (JDIMENSION)
122 jdiv_round_up((long) cinfo->image_height,
123 (long) (cinfo->max_v_samp_factor*DCTSIZE));
124 }
125
126
127 #ifdef C_MULTISCAN_FILES_SUPPORTED
128
129 LOCAL void
validate_script(j_compress_ptr cinfo)130 validate_script (j_compress_ptr cinfo)
131 /* Verify that the scan script in cinfo->scan_info[] is valid; also
132 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
133 */
134 {
135 const jpeg_scan_info * scanptr;
136 int scanno, ncomps, ci, coefi, thisi;
137 int Ss, Se, Ah, Al;
138 boolean component_sent[MAX_COMPONENTS];
139 #ifdef C_PROGRESSIVE_SUPPORTED
140 int * last_bitpos_ptr;
141 int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
142 /* -1 until that coefficient has been seen; then last Al for it */
143 #endif
144
145 if (cinfo->num_scans <= 0)
146 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
147
148 /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
149 * for progressive JPEG, no scan can have this.
150 */
151 scanptr = cinfo->scan_info;
152 if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
153 #ifdef C_PROGRESSIVE_SUPPORTED
154 cinfo->progressive_mode = TRUE;
155 last_bitpos_ptr = & last_bitpos[0][0];
156 for (ci = 0; ci < cinfo->num_components; ci++)
157 for (coefi = 0; coefi < DCTSIZE2; coefi++)
158 *last_bitpos_ptr++ = -1;
159 #else
160 ERREXIT(cinfo, JERR_NOT_COMPILED);
161 #endif
162 } else {
163 cinfo->progressive_mode = FALSE;
164 for (ci = 0; ci < cinfo->num_components; ci++)
165 component_sent[ci] = FALSE;
166 }
167
168 for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
169 /* Validate component indexes */
170 ncomps = scanptr->comps_in_scan;
171 if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
172 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
173 for (ci = 0; ci < ncomps; ci++) {
174 thisi = scanptr->component_index[ci];
175 if (thisi < 0 || thisi >= cinfo->num_components)
176 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
177 /* Components must appear in SOF order within each scan */
178 if (ci > 0 && thisi <= scanptr->component_index[ci-1])
179 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
180 }
181 /* Validate progression parameters */
182 Ss = scanptr->Ss;
183 Se = scanptr->Se;
184 Ah = scanptr->Ah;
185 Al = scanptr->Al;
186 if (cinfo->progressive_mode) {
187 #ifdef C_PROGRESSIVE_SUPPORTED
188 if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
189 Ah < 0 || Ah > 13 || Al < 0 || Al > 13)
190 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
191 if (Ss == 0) {
192 if (Se != 0) /* DC and AC together not OK */
193 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
194 } else {
195 if (ncomps != 1) /* AC scans must be for only one component */
196 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
197 }
198 for (ci = 0; ci < ncomps; ci++) {
199 last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
200 if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
201 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
202 for (coefi = Ss; coefi <= Se; coefi++) {
203 if (last_bitpos_ptr[coefi] < 0) {
204 /* first scan of this coefficient */
205 if (Ah != 0)
206 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
207 } else {
208 /* not first scan */
209 if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
210 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
211 }
212 last_bitpos_ptr[coefi] = Al;
213 }
214 }
215 #endif
216 } else {
217 /* For sequential JPEG, all progression parameters must be these: */
218 if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
219 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
220 /* Make sure components are not sent twice */
221 for (ci = 0; ci < ncomps; ci++) {
222 thisi = scanptr->component_index[ci];
223 if (component_sent[thisi])
224 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
225 component_sent[thisi] = TRUE;
226 }
227 }
228 }
229
230 /* Now verify that everything got sent. */
231 if (cinfo->progressive_mode) {
232 #ifdef C_PROGRESSIVE_SUPPORTED
233 /* For progressive mode, we only check that at least some DC data
234 * got sent for each component; the spec does not require that all bits
235 * of all coefficients be transmitted. Would it be wiser to enforce
236 * transmission of all coefficient bits??
237 */
238 for (ci = 0; ci < cinfo->num_components; ci++) {
239 if (last_bitpos[ci][0] < 0)
240 ERREXIT(cinfo, JERR_MISSING_DATA);
241 }
242 #endif
243 } else {
244 for (ci = 0; ci < cinfo->num_components; ci++) {
245 if (! component_sent[ci])
246 ERREXIT(cinfo, JERR_MISSING_DATA);
247 }
248 }
249 }
250
251 #endif /* C_MULTISCAN_FILES_SUPPORTED */
252
253
254 LOCAL void
select_scan_parameters(j_compress_ptr cinfo)255 select_scan_parameters (j_compress_ptr cinfo)
256 /* Set up the scan parameters for the current scan */
257 {
258 int ci;
259
260 #ifdef C_MULTISCAN_FILES_SUPPORTED
261 if (cinfo->scan_info != NULL) {
262 /* Prepare for current scan --- the script is already validated */
263 my_master_ptr master = (my_master_ptr) cinfo->master;
264 const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
265
266 cinfo->comps_in_scan = scanptr->comps_in_scan;
267 for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
268 cinfo->cur_comp_info[ci] =
269 &cinfo->comp_info[scanptr->component_index[ci]];
270 }
271 cinfo->Ss = scanptr->Ss;
272 cinfo->Se = scanptr->Se;
273 cinfo->Ah = scanptr->Ah;
274 cinfo->Al = scanptr->Al;
275 }
276 else
277 #endif
278 {
279 /* Prepare for single sequential-JPEG scan containing all components */
280 if (cinfo->num_components > MAX_COMPS_IN_SCAN)
281 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
282 MAX_COMPS_IN_SCAN);
283 cinfo->comps_in_scan = cinfo->num_components;
284 for (ci = 0; ci < cinfo->num_components; ci++) {
285 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
286 }
287 cinfo->Ss = 0;
288 cinfo->Se = DCTSIZE2-1;
289 cinfo->Ah = 0;
290 cinfo->Al = 0;
291 }
292 }
293
294
295 LOCAL void
per_scan_setup(j_compress_ptr cinfo)296 per_scan_setup (j_compress_ptr cinfo)
297 /* Do computations that are needed before processing a JPEG scan */
298 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
299 {
300 int ci, mcublks, tmp;
301 jpeg_component_info *compptr;
302
303 if (cinfo->comps_in_scan == 1) {
304
305 /* Noninterleaved (single-component) scan */
306 compptr = cinfo->cur_comp_info[0];
307
308 /* Overall image size in MCUs */
309 cinfo->MCUs_per_row = compptr->width_in_blocks;
310 cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
311
312 /* For noninterleaved scan, always one block per MCU */
313 compptr->MCU_width = 1;
314 compptr->MCU_height = 1;
315 compptr->MCU_blocks = 1;
316 compptr->MCU_sample_width = DCTSIZE;
317 compptr->last_col_width = 1;
318 /* For noninterleaved scans, it is convenient to define last_row_height
319 * as the number of block rows present in the last iMCU row.
320 */
321 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
322 if (tmp == 0) tmp = compptr->v_samp_factor;
323 compptr->last_row_height = tmp;
324
325 /* Prepare array describing MCU composition */
326 cinfo->blocks_in_MCU = 1;
327 cinfo->MCU_membership[0] = 0;
328
329 } else {
330
331 /* Interleaved (multi-component) scan */
332 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
333 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
334 MAX_COMPS_IN_SCAN);
335
336 /* Overall image size in MCUs */
337 cinfo->MCUs_per_row = (JDIMENSION)
338 jdiv_round_up((long) cinfo->image_width,
339 (long) (cinfo->max_h_samp_factor*DCTSIZE));
340 cinfo->MCU_rows_in_scan = (JDIMENSION)
341 jdiv_round_up((long) cinfo->image_height,
342 (long) (cinfo->max_v_samp_factor*DCTSIZE));
343
344 cinfo->blocks_in_MCU = 0;
345
346 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
347 compptr = cinfo->cur_comp_info[ci];
348 /* Sampling factors give # of blocks of component in each MCU */
349 compptr->MCU_width = compptr->h_samp_factor;
350 compptr->MCU_height = compptr->v_samp_factor;
351 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
352 compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
353 /* Figure number of non-dummy blocks in last MCU column & row */
354 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
355 if (tmp == 0) tmp = compptr->MCU_width;
356 compptr->last_col_width = tmp;
357 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
358 if (tmp == 0) tmp = compptr->MCU_height;
359 compptr->last_row_height = tmp;
360 /* Prepare array describing MCU composition */
361 mcublks = compptr->MCU_blocks;
362 if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
363 ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
364 while (mcublks-- > 0) {
365 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
366 }
367 }
368
369 }
370
371 /* Convert restart specified in rows to actual MCU count. */
372 /* Note that count must fit in 16 bits, so we provide limiting. */
373 if (cinfo->restart_in_rows > 0) {
374 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
375 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
376 }
377 }
378
379
380 /*
381 * Per-pass setup.
382 * This is called at the beginning of each pass. We determine which modules
383 * will be active during this pass and give them appropriate start_pass calls.
384 * We also set is_last_pass to indicate whether any more passes will be
385 * required.
386 */
387
388 METHODDEF void
prepare_for_pass(j_compress_ptr cinfo)389 prepare_for_pass (j_compress_ptr cinfo)
390 {
391 my_master_ptr master = (my_master_ptr) cinfo->master;
392
393 switch (master->pass_type) {
394 case main_pass:
395 /* Initial pass: will collect input data, and do either Huffman
396 * optimization or data output for the first scan.
397 */
398 select_scan_parameters(cinfo);
399 per_scan_setup(cinfo);
400 if (! cinfo->raw_data_in) {
401 (*cinfo->cconvert->start_pass) (cinfo);
402 (*cinfo->downsample->start_pass) (cinfo);
403 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
404 }
405 (*cinfo->fdct->start_pass) (cinfo);
406 (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
407 (*cinfo->coef->start_pass) (cinfo,
408 (master->total_passes > 1 ?
409 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
410 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
411 if (cinfo->optimize_coding) {
412 /* No immediate data output; postpone writing frame/scan headers */
413 master->pub.call_pass_startup = FALSE;
414 } else {
415 /* Will write frame/scan headers at first jpeg_write_scanlines call */
416 master->pub.call_pass_startup = TRUE;
417 }
418 break;
419 #ifdef ENTROPY_OPT_SUPPORTED
420 case huff_opt_pass:
421 /* Do Huffman optimization for a scan after the first one. */
422 select_scan_parameters(cinfo);
423 per_scan_setup(cinfo);
424 if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) {
425 (*cinfo->entropy->start_pass) (cinfo, TRUE);
426 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
427 master->pub.call_pass_startup = FALSE;
428 break;
429 }
430 /* Special case: Huffman DC refinement scans need no Huffman table
431 * and therefore we can skip the optimization pass for them.
432 */
433 master->pass_type = output_pass;
434 master->pass_number++;
435 /*FALLTHROUGH*/
436 #endif
437 case output_pass:
438 /* Do a data-output pass. */
439 /* We need not repeat per-scan setup if prior optimization pass did it. */
440 if (! cinfo->optimize_coding) {
441 select_scan_parameters(cinfo);
442 per_scan_setup(cinfo);
443 }
444 (*cinfo->entropy->start_pass) (cinfo, FALSE);
445 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
446 /* We emit frame/scan headers now */
447 if (master->scan_number == 0)
448 (*cinfo->marker->write_frame_header) (cinfo);
449 (*cinfo->marker->write_scan_header) (cinfo);
450 master->pub.call_pass_startup = FALSE;
451 break;
452 default:
453 ERREXIT(cinfo, JERR_NOT_COMPILED);
454 }
455
456 master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
457
458 /* Set up progress monitor's pass info if present */
459 if (cinfo->progress != NULL) {
460 cinfo->progress->completed_passes = master->pass_number;
461 cinfo->progress->total_passes = master->total_passes;
462 }
463 }
464
465
466 /*
467 * Special start-of-pass hook.
468 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
469 * In single-pass processing, we need this hook because we don't want to
470 * write frame/scan headers during jpeg_start_compress; we want to let the
471 * application write COM markers etc. between jpeg_start_compress and the
472 * jpeg_write_scanlines loop.
473 * In multi-pass processing, this routine is not used.
474 */
475
476 METHODDEF void
pass_startup(j_compress_ptr cinfo)477 pass_startup (j_compress_ptr cinfo)
478 {
479 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
480
481 (*cinfo->marker->write_frame_header) (cinfo);
482 (*cinfo->marker->write_scan_header) (cinfo);
483 }
484
485
486 /*
487 * Finish up at end of pass.
488 */
489
490 METHODDEF void
finish_pass_master(j_compress_ptr cinfo)491 finish_pass_master (j_compress_ptr cinfo)
492 {
493 my_master_ptr master = (my_master_ptr) cinfo->master;
494
495 /* The entropy coder always needs an end-of-pass call,
496 * either to analyze statistics or to flush its output buffer.
497 */
498 (*cinfo->entropy->finish_pass) (cinfo);
499
500 /* Update state for next pass */
501 switch (master->pass_type) {
502 case main_pass:
503 /* next pass is either output of scan 0 (after optimization)
504 * or output of scan 1 (if no optimization).
505 */
506 master->pass_type = output_pass;
507 if (! cinfo->optimize_coding)
508 master->scan_number++;
509 break;
510 case huff_opt_pass:
511 /* next pass is always output of current scan */
512 master->pass_type = output_pass;
513 break;
514 case output_pass:
515 /* next pass is either optimization or output of next scan */
516 if (cinfo->optimize_coding)
517 master->pass_type = huff_opt_pass;
518 master->scan_number++;
519 break;
520 }
521
522 master->pass_number++;
523 }
524
525
526 /*
527 * Initialize master compression control.
528 */
529
530 GLOBAL void
jinit_c_master_control(j_compress_ptr cinfo,boolean transcode_only)531 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
532 {
533 my_master_ptr master;
534
535 master = (my_master_ptr)
536 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
537 SIZEOF(my_comp_master));
538 cinfo->master = (struct jpeg_comp_master *) master;
539 master->pub.prepare_for_pass = prepare_for_pass;
540 master->pub.pass_startup = pass_startup;
541 master->pub.finish_pass = finish_pass_master;
542 master->pub.is_last_pass = FALSE;
543
544 /* Validate parameters, determine derived values */
545 initial_setup(cinfo);
546
547 if (cinfo->scan_info != NULL) {
548 #ifdef C_MULTISCAN_FILES_SUPPORTED
549 validate_script(cinfo);
550 #else
551 ERREXIT(cinfo, JERR_NOT_COMPILED);
552 #endif
553 } else {
554 cinfo->progressive_mode = FALSE;
555 cinfo->num_scans = 1;
556 }
557
558 if (cinfo->progressive_mode) /* TEMPORARY HACK ??? */
559 cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
560
561 /* Initialize my private state */
562 if (transcode_only) {
563 /* no main pass in transcoding */
564 if (cinfo->optimize_coding)
565 master->pass_type = huff_opt_pass;
566 else
567 master->pass_type = output_pass;
568 } else {
569 /* for normal compression, first pass is always this type: */
570 master->pass_type = main_pass;
571 }
572 master->scan_number = 0;
573 master->pass_number = 0;
574 if (cinfo->optimize_coding)
575 master->total_passes = cinfo->num_scans * 2;
576 else
577 master->total_passes = cinfo->num_scans;
578 }
579