1 /* 2 * jcparam.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1998, Thomas G. Lane. 6 * Modified 2003-2008 by Guido Vollbeding. 7 * libjpeg-turbo Modifications: 8 * Copyright (C) 2009-2011, D. R. Commander. 9 * For conditions of distribution and use, see the accompanying README.ijg 10 * file. 11 * 12 * This file contains optional default-setting code for the JPEG compressor. 13 * Applications do not have to use this file, but those that don't use it 14 * must know a lot more about the innards of the JPEG code. 15 */ 16 17 #define JPEG_INTERNALS 18 #include "jinclude.h" 19 #include "jpeglib.h" 20 #include "jstdhuff.c" 21 22 23 /* 24 * Quantization table setup routines 25 */ 26 27 GLOBAL(void) 28 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl, 29 const unsigned int *basic_table, 30 int scale_factor, boolean force_baseline) 31 /* Define a quantization table equal to the basic_table times 32 * a scale factor (given as a percentage). 33 * If force_baseline is TRUE, the computed quantization table entries 34 * are limited to 1..255 for JPEG baseline compatibility. 35 */ 36 { 37 JQUANT_TBL **qtblptr; 38 int i; 39 long temp; 40 41 /* Safety check to ensure start_compress not called yet. */ 42 if (cinfo->global_state != CSTATE_START) 43 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 44 45 if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS) 46 ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl); 47 48 qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; 49 50 if (*qtblptr == NULL) 51 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo); 52 53 for (i = 0; i < DCTSIZE2; i++) { 54 temp = ((long) basic_table[i] * scale_factor + 50L) / 100L; 55 /* limit the values to the valid range */ 56 if (temp <= 0L) temp = 1L; 57 if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */ 58 if (force_baseline && temp > 255L) 59 temp = 255L; /* limit to baseline range if requested */ 60 (*qtblptr)->quantval[i] = (UINT16) temp; 61 } 62 63 /* Initialize sent_table FALSE so table will be written to JPEG file. */ 64 (*qtblptr)->sent_table = FALSE; 65 } 66 67 68 /* These are the sample quantization tables given in JPEG spec section K.1. 69 * The spec says that the values given produce "good" quality, and 70 * when divided by 2, "very good" quality. 71 */ 72 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = { 73 16, 11, 10, 16, 24, 40, 51, 61, 74 12, 12, 14, 19, 26, 58, 60, 55, 75 14, 13, 16, 24, 40, 57, 69, 56, 76 14, 17, 22, 29, 51, 87, 80, 62, 77 18, 22, 37, 56, 68, 109, 103, 77, 78 24, 35, 55, 64, 81, 104, 113, 92, 79 49, 64, 78, 87, 103, 121, 120, 101, 80 72, 92, 95, 98, 112, 100, 103, 99 81 }; 82 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = { 83 17, 18, 24, 47, 99, 99, 99, 99, 84 18, 21, 26, 66, 99, 99, 99, 99, 85 24, 26, 56, 99, 99, 99, 99, 99, 86 47, 66, 99, 99, 99, 99, 99, 99, 87 99, 99, 99, 99, 99, 99, 99, 99, 88 99, 99, 99, 99, 99, 99, 99, 99, 89 99, 99, 99, 99, 99, 99, 99, 99, 90 99, 99, 99, 99, 99, 99, 99, 99 91 }; 92 93 94 #if JPEG_LIB_VERSION >= 70 95 GLOBAL(void) 96 jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline) 97 /* Set or change the 'quality' (quantization) setting, using default tables 98 * and straight percentage-scaling quality scales. 99 * This entry point allows different scalings for luminance and chrominance. 100 */ 101 { 102 /* Set up two quantization tables using the specified scaling */ 103 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, 104 cinfo->q_scale_factor[0], force_baseline); 105 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, 106 cinfo->q_scale_factor[1], force_baseline); 107 } 108 #endif 109 110 111 GLOBAL(void) 112 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor, 113 boolean force_baseline) 114 /* Set or change the 'quality' (quantization) setting, using default tables 115 * and a straight percentage-scaling quality scale. In most cases it's better 116 * to use jpeg_set_quality (below); this entry point is provided for 117 * applications that insist on a linear percentage scaling. 118 */ 119 { 120 /* Set up two quantization tables using the specified scaling */ 121 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, 122 scale_factor, force_baseline); 123 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, 124 scale_factor, force_baseline); 125 } 126 127 128 GLOBAL(int) 129 jpeg_quality_scaling (int quality) 130 /* Convert a user-specified quality rating to a percentage scaling factor 131 * for an underlying quantization table, using our recommended scaling curve. 132 * The input 'quality' factor should be 0 (terrible) to 100 (very good). 133 */ 134 { 135 /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */ 136 if (quality <= 0) quality = 1; 137 if (quality > 100) quality = 100; 138 139 /* The basic table is used as-is (scaling 100) for a quality of 50. 140 * Qualities 50..100 are converted to scaling percentage 200 - 2*Q; 141 * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table 142 * to make all the table entries 1 (hence, minimum quantization loss). 143 * Qualities 1..50 are converted to scaling percentage 5000/Q. 144 */ 145 if (quality < 50) 146 quality = 5000 / quality; 147 else 148 quality = 200 - quality*2; 149 150 return quality; 151 } 152 153 154 GLOBAL(void) 155 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline) 156 /* Set or change the 'quality' (quantization) setting, using default tables. 157 * This is the standard quality-adjusting entry point for typical user 158 * interfaces; only those who want detailed control over quantization tables 159 * would use the preceding three routines directly. 160 */ 161 { 162 /* Convert user 0-100 rating to percentage scaling */ 163 quality = jpeg_quality_scaling(quality); 164 165 /* Set up standard quality tables */ 166 jpeg_set_linear_quality(cinfo, quality, force_baseline); 167 } 168 169 170 /* 171 * Default parameter setup for compression. 172 * 173 * Applications that don't choose to use this routine must do their 174 * own setup of all these parameters. Alternately, you can call this 175 * to establish defaults and then alter parameters selectively. This 176 * is the recommended approach since, if we add any new parameters, 177 * your code will still work (they'll be set to reasonable defaults). 178 */ 179 180 GLOBAL(void) 181 jpeg_set_defaults (j_compress_ptr cinfo) 182 { 183 int i; 184 185 /* Safety check to ensure start_compress not called yet. */ 186 if (cinfo->global_state != CSTATE_START) 187 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 188 189 /* Allocate comp_info array large enough for maximum component count. 190 * Array is made permanent in case application wants to compress 191 * multiple images at same param settings. 192 */ 193 if (cinfo->comp_info == NULL) 194 cinfo->comp_info = (jpeg_component_info *) 195 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 196 MAX_COMPONENTS * sizeof(jpeg_component_info)); 197 198 /* Initialize everything not dependent on the color space */ 199 200 #if JPEG_LIB_VERSION >= 70 201 cinfo->scale_num = 1; /* 1:1 scaling */ 202 cinfo->scale_denom = 1; 203 #endif 204 cinfo->data_precision = BITS_IN_JSAMPLE; 205 /* Set up two quantization tables using default quality of 75 */ 206 jpeg_set_quality(cinfo, 75, TRUE); 207 /* Set up two Huffman tables */ 208 std_huff_tables((j_common_ptr) cinfo); 209 210 /* Initialize default arithmetic coding conditioning */ 211 for (i = 0; i < NUM_ARITH_TBLS; i++) { 212 cinfo->arith_dc_L[i] = 0; 213 cinfo->arith_dc_U[i] = 1; 214 cinfo->arith_ac_K[i] = 5; 215 } 216 217 /* Default is no multiple-scan output */ 218 cinfo->scan_info = NULL; 219 cinfo->num_scans = 0; 220 221 /* Expect normal source image, not raw downsampled data */ 222 cinfo->raw_data_in = FALSE; 223 224 /* Use Huffman coding, not arithmetic coding, by default */ 225 cinfo->arith_code = FALSE; 226 227 /* By default, don't do extra passes to optimize entropy coding */ 228 cinfo->optimize_coding = FALSE; 229 /* The standard Huffman tables are only valid for 8-bit data precision. 230 * If the precision is higher, force optimization on so that usable 231 * tables will be computed. This test can be removed if default tables 232 * are supplied that are valid for the desired precision. 233 */ 234 if (cinfo->data_precision > 8) 235 cinfo->optimize_coding = TRUE; 236 237 /* By default, use the simpler non-cosited sampling alignment */ 238 cinfo->CCIR601_sampling = FALSE; 239 240 #if JPEG_LIB_VERSION >= 70 241 /* By default, apply fancy downsampling */ 242 cinfo->do_fancy_downsampling = TRUE; 243 #endif 244 245 /* No input smoothing */ 246 cinfo->smoothing_factor = 0; 247 248 /* DCT algorithm preference */ 249 cinfo->dct_method = JDCT_DEFAULT; 250 251 /* No restart markers */ 252 cinfo->restart_interval = 0; 253 cinfo->restart_in_rows = 0; 254 255 /* Fill in default JFIF marker parameters. Note that whether the marker 256 * will actually be written is determined by jpeg_set_colorspace. 257 * 258 * By default, the library emits JFIF version code 1.01. 259 * An application that wants to emit JFIF 1.02 extension markers should set 260 * JFIF_minor_version to 2. We could probably get away with just defaulting 261 * to 1.02, but there may still be some decoders in use that will complain 262 * about that; saying 1.01 should minimize compatibility problems. 263 */ 264 cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */ 265 cinfo->JFIF_minor_version = 1; 266 cinfo->density_unit = 0; /* Pixel size is unknown by default */ 267 cinfo->X_density = 1; /* Pixel aspect ratio is square by default */ 268 cinfo->Y_density = 1; 269 270 /* Choose JPEG colorspace based on input space, set defaults accordingly */ 271 272 jpeg_default_colorspace(cinfo); 273 } 274 275 276 /* 277 * Select an appropriate JPEG colorspace for in_color_space. 278 */ 279 280 GLOBAL(void) 281 jpeg_default_colorspace (j_compress_ptr cinfo) 282 { 283 switch (cinfo->in_color_space) { 284 case JCS_GRAYSCALE: 285 jpeg_set_colorspace(cinfo, JCS_GRAYSCALE); 286 break; 287 case JCS_RGB: 288 case JCS_EXT_RGB: 289 case JCS_EXT_RGBX: 290 case JCS_EXT_BGR: 291 case JCS_EXT_BGRX: 292 case JCS_EXT_XBGR: 293 case JCS_EXT_XRGB: 294 case JCS_EXT_RGBA: 295 case JCS_EXT_BGRA: 296 case JCS_EXT_ABGR: 297 case JCS_EXT_ARGB: 298 jpeg_set_colorspace(cinfo, JCS_YCbCr); 299 break; 300 case JCS_YCbCr: 301 jpeg_set_colorspace(cinfo, JCS_YCbCr); 302 break; 303 case JCS_CMYK: 304 jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */ 305 break; 306 case JCS_YCCK: 307 jpeg_set_colorspace(cinfo, JCS_YCCK); 308 break; 309 case JCS_UNKNOWN: 310 jpeg_set_colorspace(cinfo, JCS_UNKNOWN); 311 break; 312 default: 313 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 314 } 315 } 316 317 318 /* 319 * Set the JPEG colorspace, and choose colorspace-dependent default values. 320 */ 321 322 GLOBAL(void) 323 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace) 324 { 325 jpeg_component_info *compptr; 326 int ci; 327 328 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \ 329 (compptr = &cinfo->comp_info[index], \ 330 compptr->component_id = (id), \ 331 compptr->h_samp_factor = (hsamp), \ 332 compptr->v_samp_factor = (vsamp), \ 333 compptr->quant_tbl_no = (quant), \ 334 compptr->dc_tbl_no = (dctbl), \ 335 compptr->ac_tbl_no = (actbl) ) 336 337 /* Safety check to ensure start_compress not called yet. */ 338 if (cinfo->global_state != CSTATE_START) 339 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 340 341 /* For all colorspaces, we use Q and Huff tables 0 for luminance components, 342 * tables 1 for chrominance components. 343 */ 344 345 cinfo->jpeg_color_space = colorspace; 346 347 cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */ 348 cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */ 349 350 switch (colorspace) { 351 case JCS_GRAYSCALE: 352 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ 353 cinfo->num_components = 1; 354 /* JFIF specifies component ID 1 */ 355 SET_COMP(0, 1, 1,1, 0, 0,0); 356 break; 357 case JCS_RGB: 358 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */ 359 cinfo->num_components = 3; 360 SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0); 361 SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0); 362 SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0); 363 break; 364 case JCS_YCbCr: 365 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ 366 cinfo->num_components = 3; 367 /* JFIF specifies component IDs 1,2,3 */ 368 /* We default to 2x2 subsamples of chrominance */ 369 SET_COMP(0, 1, 2,2, 0, 0,0); 370 SET_COMP(1, 2, 1,1, 1, 1,1); 371 SET_COMP(2, 3, 1,1, 1, 1,1); 372 break; 373 case JCS_CMYK: 374 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */ 375 cinfo->num_components = 4; 376 SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0); 377 SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0); 378 SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0); 379 SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0); 380 break; 381 case JCS_YCCK: 382 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */ 383 cinfo->num_components = 4; 384 SET_COMP(0, 1, 2,2, 0, 0,0); 385 SET_COMP(1, 2, 1,1, 1, 1,1); 386 SET_COMP(2, 3, 1,1, 1, 1,1); 387 SET_COMP(3, 4, 2,2, 0, 0,0); 388 break; 389 case JCS_UNKNOWN: 390 cinfo->num_components = cinfo->input_components; 391 if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS) 392 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 393 MAX_COMPONENTS); 394 for (ci = 0; ci < cinfo->num_components; ci++) { 395 SET_COMP(ci, ci, 1,1, 0, 0,0); 396 } 397 break; 398 default: 399 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 400 } 401 } 402 403 404 #ifdef C_PROGRESSIVE_SUPPORTED 405 406 LOCAL(jpeg_scan_info *) 407 fill_a_scan (jpeg_scan_info *scanptr, int ci, 408 int Ss, int Se, int Ah, int Al) 409 /* Support routine: generate one scan for specified component */ 410 { 411 scanptr->comps_in_scan = 1; 412 scanptr->component_index[0] = ci; 413 scanptr->Ss = Ss; 414 scanptr->Se = Se; 415 scanptr->Ah = Ah; 416 scanptr->Al = Al; 417 scanptr++; 418 return scanptr; 419 } 420 421 LOCAL(jpeg_scan_info *) 422 fill_scans (jpeg_scan_info *scanptr, int ncomps, 423 int Ss, int Se, int Ah, int Al) 424 /* Support routine: generate one scan for each component */ 425 { 426 int ci; 427 428 for (ci = 0; ci < ncomps; ci++) { 429 scanptr->comps_in_scan = 1; 430 scanptr->component_index[0] = ci; 431 scanptr->Ss = Ss; 432 scanptr->Se = Se; 433 scanptr->Ah = Ah; 434 scanptr->Al = Al; 435 scanptr++; 436 } 437 return scanptr; 438 } 439 440 LOCAL(jpeg_scan_info *) 441 fill_dc_scans (jpeg_scan_info *scanptr, int ncomps, int Ah, int Al) 442 /* Support routine: generate interleaved DC scan if possible, else N scans */ 443 { 444 int ci; 445 446 if (ncomps <= MAX_COMPS_IN_SCAN) { 447 /* Single interleaved DC scan */ 448 scanptr->comps_in_scan = ncomps; 449 for (ci = 0; ci < ncomps; ci++) 450 scanptr->component_index[ci] = ci; 451 scanptr->Ss = scanptr->Se = 0; 452 scanptr->Ah = Ah; 453 scanptr->Al = Al; 454 scanptr++; 455 } else { 456 /* Noninterleaved DC scan for each component */ 457 scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al); 458 } 459 return scanptr; 460 } 461 462 463 /* 464 * Create a recommended progressive-JPEG script. 465 * cinfo->num_components and cinfo->jpeg_color_space must be correct. 466 */ 467 468 GLOBAL(void) 469 jpeg_simple_progression (j_compress_ptr cinfo) 470 { 471 int ncomps = cinfo->num_components; 472 int nscans; 473 jpeg_scan_info *scanptr; 474 475 /* Safety check to ensure start_compress not called yet. */ 476 if (cinfo->global_state != CSTATE_START) 477 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 478 479 /* Figure space needed for script. Calculation must match code below! */ 480 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { 481 /* Custom script for YCbCr color images. */ 482 nscans = 10; 483 } else { 484 /* All-purpose script for other color spaces. */ 485 if (ncomps > MAX_COMPS_IN_SCAN) 486 nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */ 487 else 488 nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */ 489 } 490 491 /* Allocate space for script. 492 * We need to put it in the permanent pool in case the application performs 493 * multiple compressions without changing the settings. To avoid a memory 494 * leak if jpeg_simple_progression is called repeatedly for the same JPEG 495 * object, we try to re-use previously allocated space, and we allocate 496 * enough space to handle YCbCr even if initially asked for grayscale. 497 */ 498 if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) { 499 cinfo->script_space_size = MAX(nscans, 10); 500 cinfo->script_space = (jpeg_scan_info *) 501 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 502 cinfo->script_space_size * sizeof(jpeg_scan_info)); 503 } 504 scanptr = cinfo->script_space; 505 cinfo->scan_info = scanptr; 506 cinfo->num_scans = nscans; 507 508 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { 509 /* Custom script for YCbCr color images. */ 510 /* Initial DC scan */ 511 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); 512 /* Initial AC scan: get some luma data out in a hurry */ 513 scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2); 514 /* Chroma data is too small to be worth expending many scans on */ 515 scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1); 516 scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1); 517 /* Complete spectral selection for luma AC */ 518 scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2); 519 /* Refine next bit of luma AC */ 520 scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1); 521 /* Finish DC successive approximation */ 522 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); 523 /* Finish AC successive approximation */ 524 scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0); 525 scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0); 526 /* Luma bottom bit comes last since it's usually largest scan */ 527 scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0); 528 } else { 529 /* All-purpose script for other color spaces. */ 530 /* Successive approximation first pass */ 531 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); 532 scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2); 533 scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2); 534 /* Successive approximation second pass */ 535 scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1); 536 /* Successive approximation final pass */ 537 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); 538 scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0); 539 } 540 } 541 542 #endif /* C_PROGRESSIVE_SUPPORTED */ 543
