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)
jpeg_add_quant_table(j_compress_ptr cinfo,int which_tbl,const unsigned int * basic_table,int scale_factor,boolean force_baseline)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)
jpeg_default_qtables(j_compress_ptr cinfo,boolean force_baseline)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)
jpeg_set_linear_quality(j_compress_ptr cinfo,int scale_factor,boolean force_baseline)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)
jpeg_quality_scaling(int quality)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)
jpeg_set_quality(j_compress_ptr cinfo,int quality,boolean force_baseline)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)
jpeg_set_defaults(j_compress_ptr cinfo)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)
jpeg_default_colorspace(j_compress_ptr cinfo)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)
jpeg_set_colorspace(j_compress_ptr cinfo,J_COLOR_SPACE colorspace)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 *)
fill_a_scan(jpeg_scan_info * scanptr,int ci,int Ss,int Se,int Ah,int Al)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 *)
fill_scans(jpeg_scan_info * scanptr,int ncomps,int Ss,int Se,int Ah,int Al)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 *)
fill_dc_scans(jpeg_scan_info * scanptr,int ncomps,int Ah,int Al)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)
jpeg_simple_progression(j_compress_ptr cinfo)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