1 /* 2 * jcmaster.c 3 * 4 * Copyright (C) 1991-1997, 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) 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) 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 /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that 189 * seems wrong: the upper bound ought to depend on data precision. 190 * Perhaps they really meant 0..N+1 for N-bit precision. 191 * Here we allow 0..10 for 8-bit data; Al larger than 10 results in 192 * out-of-range reconstructed DC values during the first DC scan, 193 * which might cause problems for some decoders. 194 */ 195 #if BITS_IN_JSAMPLE == 8 196 #define MAX_AH_AL 10 197 #else 198 #define MAX_AH_AL 13 199 #endif 200 if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 || 201 Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL) 202 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 203 if (Ss == 0) { 204 if (Se != 0) /* DC and AC together not OK */ 205 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 206 } else { 207 if (ncomps != 1) /* AC scans must be for only one component */ 208 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 209 } 210 for (ci = 0; ci < ncomps; ci++) { 211 last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0]; 212 if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */ 213 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 214 for (coefi = Ss; coefi <= Se; coefi++) { 215 if (last_bitpos_ptr[coefi] < 0) { 216 /* first scan of this coefficient */ 217 if (Ah != 0) 218 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 219 } else { 220 /* not first scan */ 221 if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1) 222 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 223 } 224 last_bitpos_ptr[coefi] = Al; 225 } 226 } 227 #endif 228 } else { 229 /* For sequential JPEG, all progression parameters must be these: */ 230 if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0) 231 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 232 /* Make sure components are not sent twice */ 233 for (ci = 0; ci < ncomps; ci++) { 234 thisi = scanptr->component_index[ci]; 235 if (component_sent[thisi]) 236 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 237 component_sent[thisi] = TRUE; 238 } 239 } 240 } 241 242 /* Now verify that everything got sent. */ 243 if (cinfo->progressive_mode) { 244 #ifdef C_PROGRESSIVE_SUPPORTED 245 /* For progressive mode, we only check that at least some DC data 246 * got sent for each component; the spec does not require that all bits 247 * of all coefficients be transmitted. Would it be wiser to enforce 248 * transmission of all coefficient bits?? 249 */ 250 for (ci = 0; ci < cinfo->num_components; ci++) { 251 if (last_bitpos[ci][0] < 0) 252 ERREXIT(cinfo, JERR_MISSING_DATA); 253 } 254 #endif 255 } else { 256 for (ci = 0; ci < cinfo->num_components; ci++) { 257 if (! component_sent[ci]) 258 ERREXIT(cinfo, JERR_MISSING_DATA); 259 } 260 } 261 } 262 263 #endif /* C_MULTISCAN_FILES_SUPPORTED */ 264 265 266 LOCAL(void) 267 select_scan_parameters (j_compress_ptr cinfo) 268 /* Set up the scan parameters for the current scan */ 269 { 270 int ci; 271 272 #ifdef C_MULTISCAN_FILES_SUPPORTED 273 if (cinfo->scan_info != NULL) { 274 /* Prepare for current scan --- the script is already validated */ 275 my_master_ptr master = (my_master_ptr) cinfo->master; 276 const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number; 277 278 cinfo->comps_in_scan = scanptr->comps_in_scan; 279 for (ci = 0; ci < scanptr->comps_in_scan; ci++) { 280 cinfo->cur_comp_info[ci] = 281 &cinfo->comp_info[scanptr->component_index[ci]]; 282 } 283 cinfo->Ss = scanptr->Ss; 284 cinfo->Se = scanptr->Se; 285 cinfo->Ah = scanptr->Ah; 286 cinfo->Al = scanptr->Al; 287 } 288 else 289 #endif 290 { 291 /* Prepare for single sequential-JPEG scan containing all components */ 292 if (cinfo->num_components > MAX_COMPS_IN_SCAN) 293 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 294 MAX_COMPS_IN_SCAN); 295 cinfo->comps_in_scan = cinfo->num_components; 296 for (ci = 0; ci < cinfo->num_components; ci++) { 297 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci]; 298 } 299 cinfo->Ss = 0; 300 cinfo->Se = DCTSIZE2-1; 301 cinfo->Ah = 0; 302 cinfo->Al = 0; 303 } 304 } 305 306 307 LOCAL(void) 308 per_scan_setup (j_compress_ptr cinfo) 309 /* Do computations that are needed before processing a JPEG scan */ 310 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */ 311 { 312 int ci, mcublks, tmp; 313 jpeg_component_info *compptr; 314 315 if (cinfo->comps_in_scan == 1) { 316 317 /* Noninterleaved (single-component) scan */ 318 compptr = cinfo->cur_comp_info[0]; 319 320 /* Overall image size in MCUs */ 321 cinfo->MCUs_per_row = compptr->width_in_blocks; 322 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; 323 324 /* For noninterleaved scan, always one block per MCU */ 325 compptr->MCU_width = 1; 326 compptr->MCU_height = 1; 327 compptr->MCU_blocks = 1; 328 compptr->MCU_sample_width = DCTSIZE; 329 compptr->last_col_width = 1; 330 /* For noninterleaved scans, it is convenient to define last_row_height 331 * as the number of block rows present in the last iMCU row. 332 */ 333 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 334 if (tmp == 0) tmp = compptr->v_samp_factor; 335 compptr->last_row_height = tmp; 336 337 /* Prepare array describing MCU composition */ 338 cinfo->blocks_in_MCU = 1; 339 cinfo->MCU_membership[0] = 0; 340 341 } else { 342 343 /* Interleaved (multi-component) scan */ 344 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) 345 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, 346 MAX_COMPS_IN_SCAN); 347 348 /* Overall image size in MCUs */ 349 cinfo->MCUs_per_row = (JDIMENSION) 350 jdiv_round_up((long) cinfo->image_width, 351 (long) (cinfo->max_h_samp_factor*DCTSIZE)); 352 cinfo->MCU_rows_in_scan = (JDIMENSION) 353 jdiv_round_up((long) cinfo->image_height, 354 (long) (cinfo->max_v_samp_factor*DCTSIZE)); 355 356 cinfo->blocks_in_MCU = 0; 357 358 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 359 compptr = cinfo->cur_comp_info[ci]; 360 /* Sampling factors give # of blocks of component in each MCU */ 361 compptr->MCU_width = compptr->h_samp_factor; 362 compptr->MCU_height = compptr->v_samp_factor; 363 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; 364 compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE; 365 /* Figure number of non-dummy blocks in last MCU column & row */ 366 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width); 367 if (tmp == 0) tmp = compptr->MCU_width; 368 compptr->last_col_width = tmp; 369 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height); 370 if (tmp == 0) tmp = compptr->MCU_height; 371 compptr->last_row_height = tmp; 372 /* Prepare array describing MCU composition */ 373 mcublks = compptr->MCU_blocks; 374 if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU) 375 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); 376 while (mcublks-- > 0) { 377 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; 378 } 379 } 380 381 } 382 383 /* Convert restart specified in rows to actual MCU count. */ 384 /* Note that count must fit in 16 bits, so we provide limiting. */ 385 if (cinfo->restart_in_rows > 0) { 386 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row; 387 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L); 388 } 389 } 390 391 392 /* 393 * Per-pass setup. 394 * This is called at the beginning of each pass. We determine which modules 395 * will be active during this pass and give them appropriate start_pass calls. 396 * We also set is_last_pass to indicate whether any more passes will be 397 * required. 398 */ 399 400 METHODDEF(void) 401 prepare_for_pass (j_compress_ptr cinfo) 402 { 403 my_master_ptr master = (my_master_ptr) cinfo->master; 404 405 switch (master->pass_type) { 406 case main_pass: 407 /* Initial pass: will collect input data, and do either Huffman 408 * optimization or data output for the first scan. 409 */ 410 select_scan_parameters(cinfo); 411 per_scan_setup(cinfo); 412 if (! cinfo->raw_data_in) { 413 (*cinfo->cconvert->start_pass) (cinfo); 414 (*cinfo->downsample->start_pass) (cinfo); 415 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU); 416 } 417 (*cinfo->fdct->start_pass) (cinfo); 418 (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding); 419 (*cinfo->coef->start_pass) (cinfo, 420 (master->total_passes > 1 ? 421 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 422 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 423 if (cinfo->optimize_coding) { 424 /* No immediate data output; postpone writing frame/scan headers */ 425 master->pub.call_pass_startup = FALSE; 426 } else { 427 /* Will write frame/scan headers at first jpeg_write_scanlines call */ 428 master->pub.call_pass_startup = TRUE; 429 } 430 break; 431 #ifdef ENTROPY_OPT_SUPPORTED 432 case huff_opt_pass: 433 /* Do Huffman optimization for a scan after the first one. */ 434 select_scan_parameters(cinfo); 435 per_scan_setup(cinfo); 436 if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) { 437 (*cinfo->entropy->start_pass) (cinfo, TRUE); 438 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 439 master->pub.call_pass_startup = FALSE; 440 break; 441 } 442 /* Special case: Huffman DC refinement scans need no Huffman table 443 * and therefore we can skip the optimization pass for them. 444 */ 445 master->pass_type = output_pass; 446 master->pass_number++; 447 /*FALLTHROUGH*/ 448 #endif 449 case output_pass: 450 /* Do a data-output pass. */ 451 /* We need not repeat per-scan setup if prior optimization pass did it. */ 452 if (! cinfo->optimize_coding) { 453 select_scan_parameters(cinfo); 454 per_scan_setup(cinfo); 455 } 456 (*cinfo->entropy->start_pass) (cinfo, FALSE); 457 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 458 /* We emit frame/scan headers now */ 459 if (master->scan_number == 0) 460 (*cinfo->marker->write_frame_header) (cinfo); 461 (*cinfo->marker->write_scan_header) (cinfo); 462 master->pub.call_pass_startup = FALSE; 463 break; 464 default: 465 ERREXIT(cinfo, JERR_NOT_COMPILED); 466 } 467 468 master->pub.is_last_pass = (master->pass_number == master->total_passes-1); 469 470 /* Set up progress monitor's pass info if present */ 471 if (cinfo->progress != NULL) { 472 cinfo->progress->completed_passes = master->pass_number; 473 cinfo->progress->total_passes = master->total_passes; 474 } 475 } 476 477 478 /* 479 * Special start-of-pass hook. 480 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE. 481 * In single-pass processing, we need this hook because we don't want to 482 * write frame/scan headers during jpeg_start_compress; we want to let the 483 * application write COM markers etc. between jpeg_start_compress and the 484 * jpeg_write_scanlines loop. 485 * In multi-pass processing, this routine is not used. 486 */ 487 488 METHODDEF(void) 489 pass_startup (j_compress_ptr cinfo) 490 { 491 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */ 492 493 (*cinfo->marker->write_frame_header) (cinfo); 494 (*cinfo->marker->write_scan_header) (cinfo); 495 } 496 497 498 /* 499 * Finish up at end of pass. 500 */ 501 502 METHODDEF(void) 503 finish_pass_master (j_compress_ptr cinfo) 504 { 505 my_master_ptr master = (my_master_ptr) cinfo->master; 506 507 /* The entropy coder always needs an end-of-pass call, 508 * either to analyze statistics or to flush its output buffer. 509 */ 510 (*cinfo->entropy->finish_pass) (cinfo); 511 512 /* Update state for next pass */ 513 switch (master->pass_type) { 514 case main_pass: 515 /* next pass is either output of scan 0 (after optimization) 516 * or output of scan 1 (if no optimization). 517 */ 518 master->pass_type = output_pass; 519 if (! cinfo->optimize_coding) 520 master->scan_number++; 521 break; 522 case huff_opt_pass: 523 /* next pass is always output of current scan */ 524 master->pass_type = output_pass; 525 break; 526 case output_pass: 527 /* next pass is either optimization or output of next scan */ 528 if (cinfo->optimize_coding) 529 master->pass_type = huff_opt_pass; 530 master->scan_number++; 531 break; 532 } 533 534 master->pass_number++; 535 } 536 537 538 /* 539 * Initialize master compression control. 540 */ 541 542 GLOBAL(void) 543 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only) 544 { 545 my_master_ptr master; 546 547 master = (my_master_ptr) 548 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 549 SIZEOF(my_comp_master)); 550 cinfo->master = (struct jpeg_comp_master *) master; 551 master->pub.prepare_for_pass = prepare_for_pass; 552 master->pub.pass_startup = pass_startup; 553 master->pub.finish_pass = finish_pass_master; 554 master->pub.is_last_pass = FALSE; 555 556 /* Validate parameters, determine derived values */ 557 initial_setup(cinfo); 558 559 if (cinfo->scan_info != NULL) { 560 #ifdef C_MULTISCAN_FILES_SUPPORTED 561 validate_script(cinfo); 562 #else 563 ERREXIT(cinfo, JERR_NOT_COMPILED); 564 #endif 565 } else { 566 cinfo->progressive_mode = FALSE; 567 cinfo->num_scans = 1; 568 } 569 570 if (cinfo->progressive_mode) /* TEMPORARY HACK ??? */ 571 cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */ 572 573 /* Initialize my private state */ 574 if (transcode_only) { 575 /* no main pass in transcoding */ 576 if (cinfo->optimize_coding) 577 master->pass_type = huff_opt_pass; 578 else 579 master->pass_type = output_pass; 580 } else { 581 /* for normal compression, first pass is always this type: */ 582 master->pass_type = main_pass; 583 } 584 master->scan_number = 0; 585 master->pass_number = 0; 586 if (cinfo->optimize_coding) 587 master->total_passes = cinfo->num_scans * 2; 588 else 589 master->total_passes = cinfo->num_scans; 590 } 591
