1 /*
2 * jctrans.c
3 *
4 * Copyright (C) 1995-1998, Thomas G. Lane.
5 * Modified 2000-2009 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)
jpeg_write_coefficients(j_compress_ptr cinfo,jvirt_barray_ptr * coef_arrays)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)
jpeg_copy_critical_parameters(j_decompress_ptr srcinfo,j_compress_ptr dstinfo)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 */
89 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
90 dstinfo->data_precision = srcinfo->data_precision;
91 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
92 /* Copy the source's quantization tables. */
93 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
94 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
95 qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
96 if (*qtblptr == NULL)
97 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
98 MEMCOPY((*qtblptr)->quantval,
99 srcinfo->quant_tbl_ptrs[tblno]->quantval,
100 SIZEOF((*qtblptr)->quantval));
101 (*qtblptr)->sent_table = FALSE;
102 }
103 }
104 /* Copy the source's per-component info.
105 * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
106 */
107 dstinfo->num_components = srcinfo->num_components;
108 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
109 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
110 MAX_COMPONENTS);
111 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
112 ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
113 outcomp->component_id = incomp->component_id;
114 outcomp->h_samp_factor = incomp->h_samp_factor;
115 outcomp->v_samp_factor = incomp->v_samp_factor;
116 outcomp->quant_tbl_no = incomp->quant_tbl_no;
117 /* Make sure saved quantization table for component matches the qtable
118 * slot. If not, the input file re-used this qtable slot.
119 * IJG encoder currently cannot duplicate this.
120 */
121 tblno = outcomp->quant_tbl_no;
122 if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
123 srcinfo->quant_tbl_ptrs[tblno] == NULL)
124 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
125 slot_quant = srcinfo->quant_tbl_ptrs[tblno];
126 c_quant = incomp->quant_table;
127 if (c_quant != NULL) {
128 for (coefi = 0; coefi < DCTSIZE2; coefi++) {
129 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
130 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
131 }
132 }
133 /* Note: we do not copy the source's Huffman table assignments;
134 * instead we rely on jpeg_set_colorspace to have made a suitable choice.
135 */
136 }
137 /* Also copy JFIF version and resolution information, if available.
138 * Strictly speaking this isn't "critical" info, but it's nearly
139 * always appropriate to copy it if available. In particular,
140 * if the application chooses to copy JFIF 1.02 extension markers from
141 * the source file, we need to copy the version to make sure we don't
142 * emit a file that has 1.02 extensions but a claimed version of 1.01.
143 * We will *not*, however, copy version info from mislabeled "2.01" files.
144 */
145 if (srcinfo->saw_JFIF_marker) {
146 if (srcinfo->JFIF_major_version == 1) {
147 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
148 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
149 }
150 dstinfo->density_unit = srcinfo->density_unit;
151 dstinfo->X_density = srcinfo->X_density;
152 dstinfo->Y_density = srcinfo->Y_density;
153 }
154 }
155
156
157 /*
158 * Master selection of compression modules for transcoding.
159 * This substitutes for jcinit.c's initialization of the full compressor.
160 */
161
162 LOCAL(void)
transencode_master_selection(j_compress_ptr cinfo,jvirt_barray_ptr * coef_arrays)163 transencode_master_selection (j_compress_ptr cinfo,
164 jvirt_barray_ptr * coef_arrays)
165 {
166 /* Initialize master control (includes parameter checking/processing) */
167 jinit_c_master_control(cinfo, TRUE /* transcode only */);
168
169 /* Entropy encoding: either Huffman or arithmetic coding. */
170 if (cinfo->arith_code)
171 jinit_arith_encoder(cinfo);
172 else {
173 jinit_huff_encoder(cinfo);
174 }
175
176 /* We need a special coefficient buffer controller. */
177 transencode_coef_controller(cinfo, coef_arrays);
178
179 jinit_marker_writer(cinfo);
180
181 /* We can now tell the memory manager to allocate virtual arrays. */
182 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
183
184 /* Write the datastream header (SOI, JFIF) immediately.
185 * Frame and scan headers are postponed till later.
186 * This lets application insert special markers after the SOI.
187 */
188 (*cinfo->marker->write_file_header) (cinfo);
189 }
190
191
192 /*
193 * The rest of this file is a special implementation of the coefficient
194 * buffer controller. This is similar to jccoefct.c, but it handles only
195 * output from presupplied virtual arrays. Furthermore, we generate any
196 * dummy padding blocks on-the-fly rather than expecting them to be present
197 * in the arrays.
198 */
199
200 /* Private buffer controller object */
201
202 typedef struct {
203 struct jpeg_c_coef_controller pub; /* public fields */
204
205 JDIMENSION iMCU_row_num; /* iMCU row # within image */
206 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
207 int MCU_vert_offset; /* counts MCU rows within iMCU row */
208 int MCU_rows_per_iMCU_row; /* number of such rows needed */
209
210 /* Virtual block array for each component. */
211 jvirt_barray_ptr * whole_image;
212
213 /* Workspace for constructing dummy blocks at right/bottom edges. */
214 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
215 } my_coef_controller;
216
217 typedef my_coef_controller * my_coef_ptr;
218
219
220 LOCAL(void)
start_iMCU_row(j_compress_ptr cinfo)221 start_iMCU_row (j_compress_ptr cinfo)
222 /* Reset within-iMCU-row counters for a new row */
223 {
224 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
225
226 /* In an interleaved scan, an MCU row is the same as an iMCU row.
227 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
228 * But at the bottom of the image, process only what's left.
229 */
230 if (cinfo->comps_in_scan > 1) {
231 coef->MCU_rows_per_iMCU_row = 1;
232 } else {
233 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
234 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
235 else
236 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
237 }
238
239 coef->mcu_ctr = 0;
240 coef->MCU_vert_offset = 0;
241 }
242
243
244 /*
245 * Initialize for a processing pass.
246 */
247
248 METHODDEF(void)
start_pass_coef(j_compress_ptr cinfo,J_BUF_MODE pass_mode)249 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
250 {
251 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
252
253 if (pass_mode != JBUF_CRANK_DEST)
254 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
255
256 coef->iMCU_row_num = 0;
257 start_iMCU_row(cinfo);
258 }
259
260
261 /*
262 * Process some data.
263 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
264 * per call, ie, v_samp_factor block rows for each component in the scan.
265 * The data is obtained from the virtual arrays and fed to the entropy coder.
266 * Returns TRUE if the iMCU row is completed, FALSE if suspended.
267 *
268 * NB: input_buf is ignored; it is likely to be a NULL pointer.
269 */
270
271 METHODDEF(boolean)
compress_output(j_compress_ptr cinfo,JSAMPIMAGE input_buf)272 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
273 {
274 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
275 JDIMENSION MCU_col_num; /* index of current MCU within row */
276 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
277 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
278 int blkn, ci, xindex, yindex, yoffset, blockcnt;
279 JDIMENSION start_col;
280 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
281 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
282 JBLOCKROW buffer_ptr;
283 jpeg_component_info *compptr;
284
285 /* Align the virtual buffers for the components used in this scan. */
286 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
287 compptr = cinfo->cur_comp_info[ci];
288 buffer[ci] = (*cinfo->mem->access_virt_barray)
289 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
290 coef->iMCU_row_num * compptr->v_samp_factor,
291 (JDIMENSION) compptr->v_samp_factor, FALSE);
292 }
293
294 /* Loop to process one whole iMCU row */
295 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
296 yoffset++) {
297 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
298 MCU_col_num++) {
299 /* Construct list of pointers to DCT blocks belonging to this MCU */
300 blkn = 0; /* index of current DCT block within MCU */
301 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
302 compptr = cinfo->cur_comp_info[ci];
303 start_col = MCU_col_num * compptr->MCU_width;
304 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
305 : compptr->last_col_width;
306 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
307 if (coef->iMCU_row_num < last_iMCU_row ||
308 yindex+yoffset < compptr->last_row_height) {
309 /* Fill in pointers to real blocks in this row */
310 buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
311 for (xindex = 0; xindex < blockcnt; xindex++)
312 MCU_buffer[blkn++] = buffer_ptr++;
313 } else {
314 /* At bottom of image, need a whole row of dummy blocks */
315 xindex = 0;
316 }
317 /* Fill in any dummy blocks needed in this row.
318 * Dummy blocks are filled in the same way as in jccoefct.c:
319 * all zeroes in the AC entries, DC entries equal to previous
320 * block's DC value. The init routine has already zeroed the
321 * AC entries, so we need only set the DC entries correctly.
322 */
323 for (; xindex < compptr->MCU_width; xindex++) {
324 MCU_buffer[blkn] = coef->dummy_buffer[blkn];
325 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
326 blkn++;
327 }
328 }
329 }
330 /* Try to write the MCU. */
331 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
332 /* Suspension forced; update state counters and exit */
333 coef->MCU_vert_offset = yoffset;
334 coef->mcu_ctr = MCU_col_num;
335 return FALSE;
336 }
337 }
338 /* Completed an MCU row, but perhaps not an iMCU row */
339 coef->mcu_ctr = 0;
340 }
341 /* Completed the iMCU row, advance counters for next one */
342 coef->iMCU_row_num++;
343 start_iMCU_row(cinfo);
344 return TRUE;
345 }
346
347
348 /*
349 * Initialize coefficient buffer controller.
350 *
351 * Each passed coefficient array must be the right size for that
352 * coefficient: width_in_blocks wide and height_in_blocks high,
353 * with unitheight at least v_samp_factor.
354 */
355
356 LOCAL(void)
transencode_coef_controller(j_compress_ptr cinfo,jvirt_barray_ptr * coef_arrays)357 transencode_coef_controller (j_compress_ptr cinfo,
358 jvirt_barray_ptr * coef_arrays)
359 {
360 my_coef_ptr coef;
361 JBLOCKROW buffer;
362 int i;
363
364 coef = (my_coef_ptr)
365 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
366 SIZEOF(my_coef_controller));
367 cinfo->coef = (struct jpeg_c_coef_controller *) coef;
368 coef->pub.start_pass = start_pass_coef;
369 coef->pub.compress_data = compress_output;
370
371 /* Save pointer to virtual arrays */
372 coef->whole_image = coef_arrays;
373
374 /* Allocate and pre-zero space for dummy DCT blocks. */
375 buffer = (JBLOCKROW)
376 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
377 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
378 jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
379 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
380 coef->dummy_buffer[i] = buffer + i;
381 }
382 }
383