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1 | /* |
2 | * jctrans.c | |
3 | * | |
4 | * Copyright (C) 1995-1998, Thomas G. Lane. | |
5 | * This file is part of the Independent JPEG Group's software. | |
6 | * For conditions of distribution and use, see the accompanying README file. | |
7 | * | |
8 | * This file contains library routines for transcoding compression, | |
9 | * that is, writing raw DCT coefficient arrays to an output JPEG file. | |
10 | * The routines in jcapimin.c will also be needed by a transcoder. | |
11 | */ | |
12 | ||
13 | #define JPEG_INTERNALS | |
14 | #include "jinclude.h" | |
15 | #include "jpeglib.h" | |
16 | ||
17 | ||
18 | /* Forward declarations */ | |
19 | LOCAL(void) transencode_master_selection | |
20 | JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); | |
21 | LOCAL(void) transencode_coef_controller | |
22 | JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); | |
23 | ||
24 | ||
25 | /* | |
26 | * Compression initialization for writing raw-coefficient data. | |
27 | * Before calling this, all parameters and a data destination must be set up. | |
28 | * Call jpeg_finish_compress() to actually write the data. | |
29 | * | |
30 | * The number of passed virtual arrays must match cinfo->num_components. | |
31 | * Note that the virtual arrays need not be filled or even realized at | |
32 | * the time write_coefficients is called; indeed, if the virtual arrays | |
33 | * were requested from this compression object's memory manager, they | |
34 | * typically will be realized during this routine and filled afterwards. | |
35 | */ | |
36 | ||
37 | GLOBAL(void) | |
38 | jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays) | |
39 | { | |
40 | if (cinfo->global_state != CSTATE_START) | |
41 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
42 | /* Mark all tables to be written */ | |
43 | jpeg_suppress_tables(cinfo, FALSE); | |
44 | /* (Re)initialize error mgr and destination modules */ | |
45 | (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); | |
46 | (*cinfo->dest->init_destination) (cinfo); | |
47 | /* Perform master selection of active modules */ | |
48 | transencode_master_selection(cinfo, coef_arrays); | |
49 | /* Wait for jpeg_finish_compress() call */ | |
50 | cinfo->next_scanline = 0; /* so jpeg_write_marker works */ | |
51 | cinfo->global_state = CSTATE_WRCOEFS; | |
52 | } | |
53 | ||
54 | ||
55 | /* | |
56 | * Initialize the compression object with default parameters, | |
57 | * then copy from the source object all parameters needed for lossless | |
58 | * transcoding. Parameters that can be varied without loss (such as | |
59 | * scan script and Huffman optimization) are left in their default states. | |
60 | */ | |
61 | ||
62 | GLOBAL(void) | |
63 | jpeg_copy_critical_parameters (j_decompress_ptr srcinfo, | |
64 | j_compress_ptr dstinfo) | |
65 | { | |
66 | JQUANT_TBL ** qtblptr; | |
67 | jpeg_component_info *incomp, *outcomp; | |
68 | JQUANT_TBL *c_quant, *slot_quant; | |
69 | int tblno, ci, coefi; | |
70 | ||
71 | /* Safety check to ensure start_compress not called yet. */ | |
72 | if (dstinfo->global_state != CSTATE_START) | |
73 | ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state); | |
74 | /* Copy fundamental image dimensions */ | |
75 | dstinfo->image_width = srcinfo->image_width; | |
76 | dstinfo->image_height = srcinfo->image_height; | |
77 | dstinfo->input_components = srcinfo->num_components; | |
78 | dstinfo->in_color_space = srcinfo->jpeg_color_space; | |
79 | /* Initialize all parameters to default values */ | |
80 | jpeg_set_defaults(dstinfo); | |
81 | /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB. | |
82 | * Fix it to get the right header markers for the image colorspace. | |
83 | */ | |
84 | jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); | |
85 | dstinfo->data_precision = srcinfo->data_precision; | |
86 | dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; | |
87 | /* Copy the source's quantization tables. */ | |
88 | for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { | |
89 | if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { | |
90 | qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; | |
91 | if (*qtblptr == NULL) | |
92 | *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); | |
93 | MEMCOPY((*qtblptr)->quantval, | |
94 | srcinfo->quant_tbl_ptrs[tblno]->quantval, | |
95 | SIZEOF((*qtblptr)->quantval)); | |
96 | (*qtblptr)->sent_table = FALSE; | |
97 | } | |
98 | } | |
99 | /* Copy the source's per-component info. | |
100 | * Note we assume jpeg_set_defaults has allocated the dest comp_info array. | |
101 | */ | |
102 | dstinfo->num_components = srcinfo->num_components; | |
103 | if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) | |
104 | ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, | |
105 | MAX_COMPONENTS); | |
106 | for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; | |
107 | ci < dstinfo->num_components; ci++, incomp++, outcomp++) { | |
108 | outcomp->component_id = incomp->component_id; | |
109 | outcomp->h_samp_factor = incomp->h_samp_factor; | |
110 | outcomp->v_samp_factor = incomp->v_samp_factor; | |
111 | outcomp->quant_tbl_no = incomp->quant_tbl_no; | |
112 | /* Make sure saved quantization table for component matches the qtable | |
113 | * slot. If not, the input file re-used this qtable slot. | |
114 | * IJG encoder currently cannot duplicate this. | |
115 | */ | |
116 | tblno = outcomp->quant_tbl_no; | |
117 | if (tblno < 0 || tblno >= NUM_QUANT_TBLS || | |
118 | srcinfo->quant_tbl_ptrs[tblno] == NULL) | |
119 | ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); | |
120 | slot_quant = srcinfo->quant_tbl_ptrs[tblno]; | |
121 | c_quant = incomp->quant_table; | |
122 | if (c_quant != NULL) { | |
123 | for (coefi = 0; coefi < DCTSIZE2; coefi++) { | |
124 | if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) | |
125 | ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); | |
126 | } | |
127 | } | |
128 | /* Note: we do not copy the source's Huffman table assignments; | |
129 | * instead we rely on jpeg_set_colorspace to have made a suitable choice. | |
130 | */ | |
131 | } | |
132 | /* Also copy JFIF version and resolution information, if available. | |
133 | * Strictly speaking this isn't "critical" info, but it's nearly | |
134 | * always appropriate to copy it if available. In particular, | |
135 | * if the application chooses to copy JFIF 1.02 extension markers from | |
136 | * the source file, we need to copy the version to make sure we don't | |
137 | * emit a file that has 1.02 extensions but a claimed version of 1.01. | |
138 | * We will *not*, however, copy version info from mislabeled "2.01" files. | |
139 | */ | |
140 | if (srcinfo->saw_JFIF_marker) { | |
141 | if (srcinfo->JFIF_major_version == 1) { | |
142 | dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; | |
143 | dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; | |
144 | } | |
145 | dstinfo->density_unit = srcinfo->density_unit; | |
146 | dstinfo->X_density = srcinfo->X_density; | |
147 | dstinfo->Y_density = srcinfo->Y_density; | |
148 | } | |
149 | } | |
150 | ||
151 | ||
152 | /* | |
153 | * Master selection of compression modules for transcoding. | |
154 | * This substitutes for jcinit.c's initialization of the full compressor. | |
155 | */ | |
156 | ||
157 | LOCAL(void) | |
158 | transencode_master_selection (j_compress_ptr cinfo, | |
159 | jvirt_barray_ptr * coef_arrays) | |
160 | { | |
161 | /* Although we don't actually use input_components for transcoding, | |
162 | * jcmaster.c's initial_setup will complain if input_components is 0. | |
163 | */ | |
164 | cinfo->input_components = 1; | |
165 | /* Initialize master control (includes parameter checking/processing) */ | |
166 | jinit_c_master_control(cinfo, TRUE /* transcode only */); | |
167 | ||
168 | /* Entropy encoding: either Huffman or arithmetic coding. */ | |
169 | if (cinfo->arith_code) { | |
170 | ERREXIT(cinfo, JERR_ARITH_NOTIMPL); | |
171 | } else { | |
172 | if (cinfo->progressive_mode) { | |
173 | #ifdef C_PROGRESSIVE_SUPPORTED | |
174 | jinit_phuff_encoder(cinfo); | |
175 | #else | |
176 | ERREXIT(cinfo, JERR_NOT_COMPILED); | |
177 | #endif | |
178 | } else | |
179 | jinit_huff_encoder(cinfo); | |
180 | } | |
181 | ||
182 | /* We need a special coefficient buffer controller. */ | |
183 | transencode_coef_controller(cinfo, coef_arrays); | |
184 | ||
185 | jinit_marker_writer(cinfo); | |
186 | ||
187 | /* We can now tell the memory manager to allocate virtual arrays. */ | |
188 | (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); | |
189 | ||
190 | /* Write the datastream header (SOI, JFIF) immediately. | |
191 | * Frame and scan headers are postponed till later. | |
192 | * This lets application insert special markers after the SOI. | |
193 | */ | |
194 | (*cinfo->marker->write_file_header) (cinfo); | |
195 | } | |
196 | ||
197 | ||
198 | /* | |
199 | * The rest of this file is a special implementation of the coefficient | |
200 | * buffer controller. This is similar to jccoefct.c, but it handles only | |
201 | * output from presupplied virtual arrays. Furthermore, we generate any | |
202 | * dummy padding blocks on-the-fly rather than expecting them to be present | |
203 | * in the arrays. | |
204 | */ | |
205 | ||
206 | /* Private buffer controller object */ | |
207 | ||
208 | typedef struct { | |
209 | struct jpeg_c_coef_controller pub; /* public fields */ | |
210 | ||
211 | JDIMENSION iMCU_row_num; /* iMCU row # within image */ | |
212 | JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ | |
213 | int MCU_vert_offset; /* counts MCU rows within iMCU row */ | |
214 | int MCU_rows_per_iMCU_row; /* number of such rows needed */ | |
215 | ||
216 | /* Virtual block array for each component. */ | |
217 | jvirt_barray_ptr * whole_image; | |
218 | ||
219 | /* Workspace for constructing dummy blocks at right/bottom edges. */ | |
220 | JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; | |
221 | } my_coef_controller; | |
222 | ||
223 | typedef my_coef_controller * my_coef_ptr; | |
224 | ||
225 | ||
226 | LOCAL(void) | |
227 | start_iMCU_row (j_compress_ptr cinfo) | |
228 | /* Reset within-iMCU-row counters for a new row */ | |
229 | { | |
230 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; | |
231 | ||
232 | /* In an interleaved scan, an MCU row is the same as an iMCU row. | |
233 | * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. | |
234 | * But at the bottom of the image, process only what's left. | |
235 | */ | |
236 | if (cinfo->comps_in_scan > 1) { | |
237 | coef->MCU_rows_per_iMCU_row = 1; | |
238 | } else { | |
239 | if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) | |
240 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; | |
241 | else | |
242 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; | |
243 | } | |
244 | ||
245 | coef->mcu_ctr = 0; | |
246 | coef->MCU_vert_offset = 0; | |
247 | } | |
248 | ||
249 | ||
250 | /* | |
251 | * Initialize for a processing pass. | |
252 | */ | |
253 | ||
254 | METHODDEF(void) | |
255 | start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) | |
256 | { | |
257 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; | |
258 | ||
259 | if (pass_mode != JBUF_CRANK_DEST) | |
260 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); | |
261 | ||
262 | coef->iMCU_row_num = 0; | |
263 | start_iMCU_row(cinfo); | |
264 | } | |
265 | ||
266 | ||
267 | /* | |
268 | * Process some data. | |
269 | * We process the equivalent of one fully interleaved MCU row ("iMCU" row) | |
270 | * per call, ie, v_samp_factor block rows for each component in the scan. | |
271 | * The data is obtained from the virtual arrays and fed to the entropy coder. | |
272 | * Returns TRUE if the iMCU row is completed, FALSE if suspended. | |
273 | * | |
274 | * NB: input_buf is ignored; it is likely to be a NULL pointer. | |
275 | */ | |
276 | ||
277 | METHODDEF(boolean) | |
278 | compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) | |
279 | { | |
280 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; | |
281 | JDIMENSION MCU_col_num; /* index of current MCU within row */ | |
282 | JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; | |
283 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; | |
284 | int blkn, ci, xindex, yindex, yoffset, blockcnt; | |
285 | JDIMENSION start_col; | |
286 | JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; | |
287 | JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; | |
288 | JBLOCKROW buffer_ptr; | |
289 | jpeg_component_info *compptr; | |
290 | ||
291 | /* Align the virtual buffers for the components used in this scan. */ | |
292 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | |
293 | compptr = cinfo->cur_comp_info[ci]; | |
294 | buffer[ci] = (*cinfo->mem->access_virt_barray) | |
295 | ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], | |
296 | coef->iMCU_row_num * compptr->v_samp_factor, | |
297 | (JDIMENSION) compptr->v_samp_factor, FALSE); | |
298 | } | |
299 | ||
300 | /* Loop to process one whole iMCU row */ | |
301 | for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; | |
302 | yoffset++) { | |
303 | for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; | |
304 | MCU_col_num++) { | |
305 | /* Construct list of pointers to DCT blocks belonging to this MCU */ | |
306 | blkn = 0; /* index of current DCT block within MCU */ | |
307 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | |
308 | compptr = cinfo->cur_comp_info[ci]; | |
309 | start_col = MCU_col_num * compptr->MCU_width; | |
310 | blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width | |
311 | : compptr->last_col_width; | |
312 | for (yindex = 0; yindex < compptr->MCU_height; yindex++) { | |
313 | if (coef->iMCU_row_num < last_iMCU_row || | |
314 | yindex+yoffset < compptr->last_row_height) { | |
315 | /* Fill in pointers to real blocks in this row */ | |
316 | buffer_ptr = buffer[ci][yindex+yoffset] + start_col; | |
317 | for (xindex = 0; xindex < blockcnt; xindex++) | |
318 | MCU_buffer[blkn++] = buffer_ptr++; | |
319 | } else { | |
320 | /* At bottom of image, need a whole row of dummy blocks */ | |
321 | xindex = 0; | |
322 | } | |
323 | /* Fill in any dummy blocks needed in this row. | |
324 | * Dummy blocks are filled in the same way as in jccoefct.c: | |
325 | * all zeroes in the AC entries, DC entries equal to previous | |
326 | * block's DC value. The init routine has already zeroed the | |
327 | * AC entries, so we need only set the DC entries correctly. | |
328 | */ | |
329 | for (; xindex < compptr->MCU_width; xindex++) { | |
330 | MCU_buffer[blkn] = coef->dummy_buffer[blkn]; | |
331 | MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; | |
332 | blkn++; | |
333 | } | |
334 | } | |
335 | } | |
336 | /* Try to write the MCU. */ | |
337 | if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { | |
338 | /* Suspension forced; update state counters and exit */ | |
339 | coef->MCU_vert_offset = yoffset; | |
340 | coef->mcu_ctr = MCU_col_num; | |
341 | return FALSE; | |
342 | } | |
343 | } | |
344 | /* Completed an MCU row, but perhaps not an iMCU row */ | |
345 | coef->mcu_ctr = 0; | |
346 | } | |
347 | /* Completed the iMCU row, advance counters for next one */ | |
348 | coef->iMCU_row_num++; | |
349 | start_iMCU_row(cinfo); | |
350 | return TRUE; | |
351 | } | |
352 | ||
353 | ||
354 | /* | |
355 | * Initialize coefficient buffer controller. | |
356 | * | |
357 | * Each passed coefficient array must be the right size for that | |
358 | * coefficient: width_in_blocks wide and height_in_blocks high, | |
359 | * with unitheight at least v_samp_factor. | |
360 | */ | |
361 | ||
362 | LOCAL(void) | |
363 | transencode_coef_controller (j_compress_ptr cinfo, | |
364 | jvirt_barray_ptr * coef_arrays) | |
365 | { | |
366 | my_coef_ptr coef; | |
367 | JBLOCKROW buffer; | |
368 | int i; | |
369 | ||
370 | coef = (my_coef_ptr) | |
371 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
372 | SIZEOF(my_coef_controller)); | |
373 | cinfo->coef = (struct jpeg_c_coef_controller *) coef; | |
374 | coef->pub.start_pass = start_pass_coef; | |
375 | coef->pub.compress_data = compress_output; | |
376 | ||
377 | /* Save pointer to virtual arrays */ | |
378 | coef->whole_image = coef_arrays; | |
379 | ||
380 | /* Allocate and pre-zero space for dummy DCT blocks. */ | |
381 | buffer = (JBLOCKROW) | |
382 | (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
383 | C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); | |
384 | jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); | |
385 | for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { | |
386 | coef->dummy_buffer[i] = buffer + i; | |
387 | } | |
388 | } |