1 /*
2 * jctrans.c
3 *
4 * Copyright (C) 1995-1998, Thomas G. Lane.
5 * Modified 2000-2017 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
8 *
9 * This file contains library routines for transcoding compression,
10 * that is, writing raw DCT coefficient arrays to an output JPEG file.
11 * The routines in jcapimin.c will also be needed by a transcoder.
12 */
13
14 #define JPEG_INTERNALS
15 #include "jinclude.h"
16 #include "jpeglib.h"
17
18
19 /* Forward declarations */
20 LOCAL(void) transencode_master_selection
21 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
22 LOCAL(void) transencode_coef_controller
23 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
24
25
26 /*
27 * Compression initialization for writing raw-coefficient data.
28 * Before calling this, all parameters and a data destination must be set up.
29 * Call jpeg_finish_compress() to actually write the data.
30 *
31 * The number of passed virtual arrays must match cinfo->num_components.
32 * Note that the virtual arrays need not be filled or even realized at
33 * the time write_coefficients is called; indeed, if the virtual arrays
34 * were requested from this compression object's memory manager, they
35 * typically will be realized during this routine and filled afterwards.
36 */
37
38 GLOBAL(void)
39 jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
40 {
41 if (cinfo->global_state != CSTATE_START)
42 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
43 /* Mark all tables to be written */
44 jpeg_suppress_tables(cinfo, FALSE);
45 /* (Re)initialize error mgr and destination modules */
46 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
47 (*cinfo->dest->init_destination) (cinfo);
48 /* Perform master selection of active modules */
49 transencode_master_selection(cinfo, coef_arrays);
50 /* Wait for jpeg_finish_compress() call */
51 cinfo->next_scanline = 0; /* so jpeg_write_marker works */
52 cinfo->global_state = CSTATE_WRCOEFS;
53 }
54
55
56 /*
57 * Initialize the compression object with default parameters,
58 * then copy from the source object all parameters needed for lossless
59 * transcoding. Parameters that can be varied without loss (such as
60 * scan script and Huffman optimization) are left in their default states.
61 */
62
63 GLOBAL(void)
64 jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
65 j_compress_ptr dstinfo)
66 {
67 JQUANT_TBL ** qtblptr;
68 jpeg_component_info *incomp, *outcomp;
69 JQUANT_TBL *c_quant, *slot_quant;
70 int tblno, ci, coefi;
71
72 /* Safety check to ensure start_compress not called yet. */
73 if (dstinfo->global_state != CSTATE_START)
74 ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
75 /* Copy fundamental image dimensions */
76 dstinfo->image_width = srcinfo->image_width;
77 dstinfo->image_height = srcinfo->image_height;
78 dstinfo->input_components = srcinfo->num_components;
79 dstinfo->in_color_space = srcinfo->jpeg_color_space;
80 dstinfo->jpeg_width = srcinfo->output_width;
81 dstinfo->jpeg_height = srcinfo->output_height;
82 dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size;
83 dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size;
84 /* Initialize all parameters to default values */
85 jpeg_set_defaults(dstinfo);
86 /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
87 * Fix it to get the right header markers for the image colorspace.
88 * Note: Entropy table assignment in jpeg_set_colorspace
89 * depends on color_transform.
90 * Adaption is also required for setting the appropriate
91 * entropy coding mode dependent on image data precision.
92 */
93 dstinfo->color_transform = srcinfo->color_transform;
94 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
95 dstinfo->data_precision = srcinfo->data_precision;
96 dstinfo->arith_code = srcinfo->data_precision > 8 ? TRUE : FALSE;
97 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
98 /* Copy the source's quantization tables. */
99 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
100 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
101 qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
102 if (*qtblptr == NULL)
103 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
104 MEMCOPY((*qtblptr)->quantval,
105 srcinfo->quant_tbl_ptrs[tblno]->quantval,
106 SIZEOF((*qtblptr)->quantval));
107 (*qtblptr)->sent_table = FALSE;
108 }
109 }
110 /* Copy the source's per-component info.
111 * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
112 */
113 dstinfo->num_components = srcinfo->num_components;
114 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
115 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
116 MAX_COMPONENTS);
117 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
118 ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
119 outcomp->component_id = incomp->component_id;
120 outcomp->h_samp_factor = incomp->h_samp_factor;
121 outcomp->v_samp_factor = incomp->v_samp_factor;
122 outcomp->quant_tbl_no = incomp->quant_tbl_no;
123 /* Make sure saved quantization table for component matches the qtable
124 * slot. If not, the input file re-used this qtable slot.
125 * IJG encoder currently cannot duplicate this.
126 */
127 tblno = outcomp->quant_tbl_no;
128 if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
129 srcinfo->quant_tbl_ptrs[tblno] == NULL)
130 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
131 slot_quant = srcinfo->quant_tbl_ptrs[tblno];
132 c_quant = incomp->quant_table;
133 if (c_quant != NULL) {
134 for (coefi = 0; coefi < DCTSIZE2; coefi++) {
135 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
136 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
137 }
138 }
139 /* Note: we do not copy the source's entropy table assignments;
140 * instead we rely on jpeg_set_colorspace to have made a suitable choice.
141 */
142 }
143 /* Also copy JFIF version and resolution information, if available.
144 * Strictly speaking this isn't "critical" info, but it's nearly
145 * always appropriate to copy it if available. In particular,
146 * if the application chooses to copy JFIF 1.02 extension markers from
147 * the source file, we need to copy the version to make sure we don't
148 * emit a file that has 1.02 extensions but a claimed version of 1.01.
149 */
150 if (srcinfo->saw_JFIF_marker) {
151 if (srcinfo->JFIF_major_version == 1 ||
152 srcinfo->JFIF_major_version == 2) {
153 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
154 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
155 }
156 dstinfo->density_unit = srcinfo->density_unit;
157 dstinfo->X_density = srcinfo->X_density;
158 dstinfo->Y_density = srcinfo->Y_density;
159 }
160 }
161
162
163 LOCAL(void)
164 jpeg_calc_trans_dimensions (j_compress_ptr cinfo)
165 /* Do computations that are needed before master selection phase */
166 {
167 if (cinfo->min_DCT_h_scaled_size != cinfo->min_DCT_v_scaled_size)
168 ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
169 cinfo->min_DCT_h_scaled_size, cinfo->min_DCT_v_scaled_size);
170
171 cinfo->block_size = cinfo->min_DCT_h_scaled_size;
172 }
173
174
175 /*
176 * Master selection of compression modules for transcoding.
177 * This substitutes for jcinit.c's initialization of the full compressor.
178 */
179
180 LOCAL(void)
181 transencode_master_selection (j_compress_ptr cinfo,
182 jvirt_barray_ptr * coef_arrays)
183 {
184 /* Do computations that are needed before master selection phase */
185 jpeg_calc_trans_dimensions(cinfo);
186
187 /* Initialize master control (includes parameter checking/processing) */
188 jinit_c_master_control(cinfo, TRUE /* transcode only */);
189
190 /* Entropy encoding: either Huffman or arithmetic coding. */
191 if (cinfo->arith_code) {
192 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
193 } else {
194 jinit_huff_encoder(cinfo);
195 }
196
197 /* We need a special coefficient buffer controller. */
198 transencode_coef_controller(cinfo, coef_arrays);
199
200 jinit_marker_writer(cinfo);
201
202 /* We can now tell the memory manager to allocate virtual arrays. */
203 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
204
205 /* Write the datastream header (SOI, JFIF) immediately.
206 * Frame and scan headers are postponed till later.
207 * This lets application insert special markers after the SOI.
208 */
209 (*cinfo->marker->write_file_header) (cinfo);
210 }
211
212
213 /*
214 * The rest of this file is a special implementation of the coefficient
215 * buffer controller. This is similar to jccoefct.c, but it handles only
216 * output from presupplied virtual arrays. Furthermore, we generate any
217 * dummy padding blocks on-the-fly rather than expecting them to be present
218 * in the arrays.
219 */
220
221 /* Private buffer controller object */
222
223 typedef struct {
224 struct jpeg_c_coef_controller pub; /* public fields */
225
226 JDIMENSION iMCU_row_num; /* iMCU row # within image */
227 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
228 int MCU_vert_offset; /* counts MCU rows within iMCU row */
229 int MCU_rows_per_iMCU_row; /* number of such rows needed */
230
231 /* Virtual block array for each component. */
232 jvirt_barray_ptr * whole_image;
233
234 /* Workspace for constructing dummy blocks at right/bottom edges. */
235 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
236 } my_coef_controller;
237
238 typedef my_coef_controller * my_coef_ptr;
239
240
241 LOCAL(void)
242 start_iMCU_row (j_compress_ptr cinfo)
243 /* Reset within-iMCU-row counters for a new row */
244 {
245 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
246
247 /* In an interleaved scan, an MCU row is the same as an iMCU row.
248 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
249 * But at the bottom of the image, process only what's left.
250 */
251 if (cinfo->comps_in_scan > 1) {
252 coef->MCU_rows_per_iMCU_row = 1;
253 } else {
254 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
255 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
256 else
257 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
258 }
259
260 coef->mcu_ctr = 0;
261 coef->MCU_vert_offset = 0;
262 }
263
264
265 /*
266 * Initialize for a processing pass.
267 */
268
269 METHODDEF(void)
270 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
271 {
272 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
273
274 if (pass_mode != JBUF_CRANK_DEST)
275 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
276
277 coef->iMCU_row_num = 0;
278 start_iMCU_row(cinfo);
279 }
280
281
282 /*
283 * Process some data.
284 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
285 * per call, ie, v_samp_factor block rows for each component in the scan.
286 * The data is obtained from the virtual arrays and fed to the entropy coder.
287 * Returns TRUE if the iMCU row is completed, FALSE if suspended.
288 *
289 * NB: input_buf is ignored; it is likely to be a NULL pointer.
290 */
291
292 METHODDEF(boolean)
293 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
294 {
295 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
296 JDIMENSION MCU_col_num; /* index of current MCU within row */
297 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
298 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
299 int blkn, ci, xindex, yindex, yoffset, blockcnt;
300 JDIMENSION start_col;
301 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
302 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
303 JBLOCKROW buffer_ptr;
304 jpeg_component_info *compptr;
305
306 /* Align the virtual buffers for the components used in this scan. */
307 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
308 compptr = cinfo->cur_comp_info[ci];
309 buffer[ci] = (*cinfo->mem->access_virt_barray)
310 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
311 coef->iMCU_row_num * compptr->v_samp_factor,
312 (JDIMENSION) compptr->v_samp_factor, FALSE);
313 }
314
315 /* Loop to process one whole iMCU row */
316 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
317 yoffset++) {
318 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
319 MCU_col_num++) {
320 /* Construct list of pointers to DCT blocks belonging to this MCU */
321 blkn = 0; /* index of current DCT block within MCU */
322 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
323 compptr = cinfo->cur_comp_info[ci];
324 start_col = MCU_col_num * compptr->MCU_width;
325 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
326 : compptr->last_col_width;
327 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
328 if (coef->iMCU_row_num < last_iMCU_row ||
329 yindex+yoffset < compptr->last_row_height) {
330 /* Fill in pointers to real blocks in this row */
331 buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
332 for (xindex = 0; xindex < blockcnt; xindex++)
333 MCU_buffer[blkn++] = buffer_ptr++;
334 } else {
335 /* At bottom of image, need a whole row of dummy blocks */
336 xindex = 0;
337 }
338 /* Fill in any dummy blocks needed in this row.
339 * Dummy blocks are filled in the same way as in jccoefct.c:
340 * all zeroes in the AC entries, DC entries equal to previous
341 * block's DC value. The init routine has already zeroed the
342 * AC entries, so we need only set the DC entries correctly.
343 */
344 for (; xindex < compptr->MCU_width; xindex++) {
345 MCU_buffer[blkn] = coef->dummy_buffer[blkn];
346 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
347 blkn++;
348 }
349 }
350 }
351 /* Try to write the MCU. */
352 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
353 /* Suspension forced; update state counters and exit */
354 coef->MCU_vert_offset = yoffset;
355 coef->mcu_ctr = MCU_col_num;
356 return FALSE;
357 }
358 }
359 /* Completed an MCU row, but perhaps not an iMCU row */
360 coef->mcu_ctr = 0;
361 }
362 /* Completed the iMCU row, advance counters for next one */
363 coef->iMCU_row_num++;
364 start_iMCU_row(cinfo);
365 return TRUE;
366 }
367
368
369 /*
370 * Initialize coefficient buffer controller.
371 *
372 * Each passed coefficient array must be the right size for that
373 * coefficient: width_in_blocks wide and height_in_blocks high,
374 * with unitheight at least v_samp_factor.
375 */
376
377 LOCAL(void)
378 transencode_coef_controller (j_compress_ptr cinfo,
379 jvirt_barray_ptr * coef_arrays)
380 {
381 my_coef_ptr coef;
382 JBLOCKROW buffer;
383 int i;
384
385 coef = (my_coef_ptr)
386 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
387 SIZEOF(my_coef_controller));
388 cinfo->coef = &coef->pub;
389 coef->pub.start_pass = start_pass_coef;
390 coef->pub.compress_data = compress_output;
391
392 /* Save pointer to virtual arrays */
393 coef->whole_image = coef_arrays;
394
395 /* Allocate and pre-zero space for dummy DCT blocks. */
396 buffer = (JBLOCKROW)
397 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
398 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
399 FMEMZERO((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
400 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
401 coef->dummy_buffer[i] = buffer + i;
402 }
403 }