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