1 | /* |
2 | * jctrans.c |
3 | * |
4 | * This file was part of the Independent JPEG Group's software: |
5 | * Copyright (C) 1995-1998, Thomas G. Lane. |
6 | * Modified 2000-2009 by Guido Vollbeding. |
7 | * libjpeg-turbo Modifications: |
8 | * Copyright (C) 2020, D. R. Commander. |
9 | * For conditions of distribution and use, see the accompanying README.ijg |
10 | * file. |
11 | * |
12 | * This file contains library routines for transcoding compression, |
13 | * that is, writing raw DCT coefficient arrays to an output JPEG file. |
14 | * The routines in jcapimin.c will also be needed by a transcoder. |
15 | */ |
16 | |
17 | #define JPEG_INTERNALS |
18 | #include "jinclude.h" |
19 | #include "jpeglib.h" |
20 | #include "jpegcomp.h" |
21 | |
22 | |
23 | /* Forward declarations */ |
24 | LOCAL(void) transencode_master_selection(j_compress_ptr cinfo, |
25 | jvirt_barray_ptr *coef_arrays); |
26 | LOCAL(void) transencode_coef_controller(j_compress_ptr cinfo, |
27 | jvirt_barray_ptr *coef_arrays); |
28 | |
29 | |
30 | /* |
31 | * Compression initialization for writing raw-coefficient data. |
32 | * Before calling this, all parameters and a data destination must be set up. |
33 | * Call jpeg_finish_compress() to actually write the data. |
34 | * |
35 | * The number of passed virtual arrays must match cinfo->num_components. |
36 | * Note that the virtual arrays need not be filled or even realized at |
37 | * the time write_coefficients is called; indeed, if the virtual arrays |
38 | * were requested from this compression object's memory manager, they |
39 | * typically will be realized during this routine and filled afterwards. |
40 | */ |
41 | |
42 | GLOBAL(void) |
43 | jpeg_write_coefficients(j_compress_ptr cinfo, jvirt_barray_ptr *coef_arrays) |
44 | { |
45 | if (cinfo->global_state != CSTATE_START) |
46 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
47 | /* Mark all tables to be written */ |
48 | jpeg_suppress_tables(cinfo, FALSE); |
49 | /* (Re)initialize error mgr and destination modules */ |
50 | (*cinfo->err->reset_error_mgr) ((j_common_ptr)cinfo); |
51 | (*cinfo->dest->init_destination) (cinfo); |
52 | /* Perform master selection of active modules */ |
53 | transencode_master_selection(cinfo, coef_arrays); |
54 | /* Wait for jpeg_finish_compress() call */ |
55 | cinfo->next_scanline = 0; /* so jpeg_write_marker works */ |
56 | cinfo->global_state = CSTATE_WRCOEFS; |
57 | } |
58 | |
59 | |
60 | /* |
61 | * Initialize the compression object with default parameters, |
62 | * then copy from the source object all parameters needed for lossless |
63 | * transcoding. Parameters that can be varied without loss (such as |
64 | * scan script and Huffman optimization) are left in their default states. |
65 | */ |
66 | |
67 | GLOBAL(void) |
68 | jpeg_copy_critical_parameters(j_decompress_ptr srcinfo, j_compress_ptr dstinfo) |
69 | { |
70 | JQUANT_TBL **qtblptr; |
71 | jpeg_component_info *incomp, *outcomp; |
72 | JQUANT_TBL *c_quant, *slot_quant; |
73 | int tblno, ci, coefi; |
74 | |
75 | /* Safety check to ensure start_compress not called yet. */ |
76 | if (dstinfo->global_state != CSTATE_START) |
77 | ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state); |
78 | /* Copy fundamental image dimensions */ |
79 | dstinfo->image_width = srcinfo->image_width; |
80 | dstinfo->image_height = srcinfo->image_height; |
81 | dstinfo->input_components = srcinfo->num_components; |
82 | dstinfo->in_color_space = srcinfo->jpeg_color_space; |
83 | #if JPEG_LIB_VERSION >= 70 |
84 | dstinfo->jpeg_width = srcinfo->output_width; |
85 | dstinfo->jpeg_height = srcinfo->output_height; |
86 | dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size; |
87 | dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size; |
88 | #endif |
89 | /* Initialize all parameters to default values */ |
90 | jpeg_set_defaults(dstinfo); |
91 | /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB. |
92 | * Fix it to get the right header markers for the image colorspace. |
93 | */ |
94 | jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); |
95 | dstinfo->data_precision = srcinfo->data_precision; |
96 | dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; |
97 | /* Copy the source's quantization tables. */ |
98 | for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { |
99 | if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { |
100 | qtblptr = &dstinfo->quant_tbl_ptrs[tblno]; |
101 | if (*qtblptr == NULL) |
102 | *qtblptr = jpeg_alloc_quant_table((j_common_ptr)dstinfo); |
103 | MEMCOPY((*qtblptr)->quantval, srcinfo->quant_tbl_ptrs[tblno]->quantval, |
104 | sizeof((*qtblptr)->quantval)); |
105 | (*qtblptr)->sent_table = FALSE; |
106 | } |
107 | } |
108 | /* Copy the source's per-component info. |
109 | * Note we assume jpeg_set_defaults has allocated the dest comp_info array. |
110 | */ |
111 | dstinfo->num_components = srcinfo->num_components; |
112 | if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) |
113 | ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, |
114 | MAX_COMPONENTS); |
115 | for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; |
116 | ci < dstinfo->num_components; ci++, incomp++, outcomp++) { |
117 | outcomp->component_id = incomp->component_id; |
118 | outcomp->h_samp_factor = incomp->h_samp_factor; |
119 | outcomp->v_samp_factor = incomp->v_samp_factor; |
120 | outcomp->quant_tbl_no = incomp->quant_tbl_no; |
121 | /* Make sure saved quantization table for component matches the qtable |
122 | * slot. If not, the input file re-used this qtable slot. |
123 | * IJG encoder currently cannot duplicate this. |
124 | */ |
125 | tblno = outcomp->quant_tbl_no; |
126 | if (tblno < 0 || tblno >= NUM_QUANT_TBLS || |
127 | srcinfo->quant_tbl_ptrs[tblno] == NULL) |
128 | ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); |
129 | slot_quant = srcinfo->quant_tbl_ptrs[tblno]; |
130 | c_quant = incomp->quant_table; |
131 | if (c_quant != NULL) { |
132 | for (coefi = 0; coefi < DCTSIZE2; coefi++) { |
133 | if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) |
134 | ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); |
135 | } |
136 | } |
137 | /* Note: we do not copy the source's Huffman table assignments; |
138 | * instead we rely on jpeg_set_colorspace to have made a suitable choice. |
139 | */ |
140 | } |
141 | /* Also copy JFIF version and resolution information, if available. |
142 | * Strictly speaking this isn't "critical" info, but it's nearly |
143 | * always appropriate to copy it if available. In particular, |
144 | * if the application chooses to copy JFIF 1.02 extension markers from |
145 | * the source file, we need to copy the version to make sure we don't |
146 | * emit a file that has 1.02 extensions but a claimed version of 1.01. |
147 | * We will *not*, however, copy version info from mislabeled "2.01" files. |
148 | */ |
149 | if (srcinfo->saw_JFIF_marker) { |
150 | if (srcinfo->JFIF_major_version == 1) { |
151 | dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; |
152 | dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; |
153 | } |
154 | dstinfo->density_unit = srcinfo->density_unit; |
155 | dstinfo->X_density = srcinfo->X_density; |
156 | dstinfo->Y_density = srcinfo->Y_density; |
157 | } |
158 | } |
159 | |
160 | |
161 | /* |
162 | * Master selection of compression modules for transcoding. |
163 | * This substitutes for jcinit.c's initialization of the full compressor. |
164 | */ |
165 | |
166 | LOCAL(void) |
167 | transencode_master_selection(j_compress_ptr cinfo, |
168 | jvirt_barray_ptr *coef_arrays) |
169 | { |
170 | /* Although we don't actually use input_components for transcoding, |
171 | * jcmaster.c's initial_setup will complain if input_components is 0. |
172 | */ |
173 | cinfo->input_components = 1; |
174 | /* Initialize master control (includes parameter checking/processing) */ |
175 | jinit_c_master_control(cinfo, TRUE /* transcode only */); |
176 | |
177 | /* Entropy encoding: either Huffman or arithmetic coding. */ |
178 | if (cinfo->arith_code) { |
179 | #ifdef C_ARITH_CODING_SUPPORTED |
180 | jinit_arith_encoder(cinfo); |
181 | #else |
182 | ERREXIT(cinfo, JERR_ARITH_NOTIMPL); |
183 | #endif |
184 | } else { |
185 | if (cinfo->progressive_mode) { |
186 | #ifdef C_PROGRESSIVE_SUPPORTED |
187 | jinit_phuff_encoder(cinfo); |
188 | #else |
189 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
190 | #endif |
191 | } else |
192 | jinit_huff_encoder(cinfo); |
193 | } |
194 | |
195 | /* We need a special coefficient buffer controller. */ |
196 | transencode_coef_controller(cinfo, coef_arrays); |
197 | |
198 | jinit_marker_writer(cinfo); |
199 | |
200 | /* We can now tell the memory manager to allocate virtual arrays. */ |
201 | (*cinfo->mem->realize_virt_arrays) ((j_common_ptr)cinfo); |
202 | |
203 | /* Write the datastream header (SOI, JFIF) immediately. |
204 | * Frame and scan headers are postponed till later. |
205 | * This lets application insert special markers after the SOI. |
206 | */ |
207 | (*cinfo->marker->write_file_header) (cinfo); |
208 | } |
209 | |
210 | |
211 | /* |
212 | * The rest of this file is a special implementation of the coefficient |
213 | * buffer controller. This is similar to jccoefct.c, but it handles only |
214 | * output from presupplied virtual arrays. Furthermore, we generate any |
215 | * dummy padding blocks on-the-fly rather than expecting them to be present |
216 | * in the arrays. |
217 | */ |
218 | |
219 | /* Private buffer controller object */ |
220 | |
221 | typedef struct { |
222 | struct jpeg_c_coef_controller pub; /* public fields */ |
223 | |
224 | JDIMENSION iMCU_row_num; /* iMCU row # within image */ |
225 | JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ |
226 | int MCU_vert_offset; /* counts MCU rows within iMCU row */ |
227 | int MCU_rows_per_iMCU_row; /* number of such rows needed */ |
228 | |
229 | /* Virtual block array for each component. */ |
230 | jvirt_barray_ptr *whole_image; |
231 | |
232 | /* Workspace for constructing dummy blocks at right/bottom edges. */ |
233 | JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; |
234 | } my_coef_controller; |
235 | |
236 | typedef my_coef_controller *my_coef_ptr; |
237 | |
238 | |
239 | LOCAL(void) |
240 | start_iMCU_row(j_compress_ptr cinfo) |
241 | /* Reset within-iMCU-row counters for a new row */ |
242 | { |
243 | my_coef_ptr coef = (my_coef_ptr)cinfo->coef; |
244 | |
245 | /* In an interleaved scan, an MCU row is the same as an iMCU row. |
246 | * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. |
247 | * But at the bottom of the image, process only what's left. |
248 | */ |
249 | if (cinfo->comps_in_scan > 1) { |
250 | coef->MCU_rows_per_iMCU_row = 1; |
251 | } else { |
252 | if (coef->iMCU_row_num < (cinfo->total_iMCU_rows - 1)) |
253 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; |
254 | else |
255 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; |
256 | } |
257 | |
258 | coef->mcu_ctr = 0; |
259 | coef->MCU_vert_offset = 0; |
260 | } |
261 | |
262 | |
263 | /* |
264 | * Initialize for a processing pass. |
265 | */ |
266 | |
267 | METHODDEF(void) |
268 | start_pass_coef(j_compress_ptr cinfo, J_BUF_MODE pass_mode) |
269 | { |
270 | my_coef_ptr coef = (my_coef_ptr)cinfo->coef; |
271 | |
272 | if (pass_mode != JBUF_CRANK_DEST) |
273 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
274 | |
275 | coef->iMCU_row_num = 0; |
276 | start_iMCU_row(cinfo); |
277 | } |
278 | |
279 | |
280 | /* |
281 | * Process some data. |
282 | * We process the equivalent of one fully interleaved MCU row ("iMCU" row) |
283 | * per call, ie, v_samp_factor block rows for each component in the scan. |
284 | * The data is obtained from the virtual arrays and fed to the entropy coder. |
285 | * Returns TRUE if the iMCU row is completed, FALSE if suspended. |
286 | * |
287 | * NB: input_buf is ignored; it is likely to be a NULL pointer. |
288 | */ |
289 | |
290 | METHODDEF(boolean) |
291 | compress_output(j_compress_ptr cinfo, JSAMPIMAGE input_buf) |
292 | { |
293 | my_coef_ptr coef = (my_coef_ptr)cinfo->coef; |
294 | JDIMENSION MCU_col_num; /* index of current MCU within row */ |
295 | JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; |
296 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; |
297 | int blkn, ci, xindex, yindex, yoffset, blockcnt; |
298 | JDIMENSION start_col; |
299 | JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; |
300 | JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; |
301 | JBLOCKROW buffer_ptr; |
302 | jpeg_component_info *compptr; |
303 | |
304 | /* Align the virtual buffers for the components used in this scan. */ |
305 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
306 | compptr = cinfo->cur_comp_info[ci]; |
307 | buffer[ci] = (*cinfo->mem->access_virt_barray) |
308 | ((j_common_ptr)cinfo, coef->whole_image[compptr->component_index], |
309 | coef->iMCU_row_num * compptr->v_samp_factor, |
310 | (JDIMENSION)compptr->v_samp_factor, FALSE); |
311 | } |
312 | |
313 | /* Loop to process one whole iMCU row */ |
314 | for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; |
315 | yoffset++) { |
316 | for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; |
317 | MCU_col_num++) { |
318 | /* Construct list of pointers to DCT blocks belonging to this MCU */ |
319 | blkn = 0; /* index of current DCT block within MCU */ |
320 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
321 | compptr = cinfo->cur_comp_info[ci]; |
322 | start_col = MCU_col_num * compptr->MCU_width; |
323 | blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width : |
324 | compptr->last_col_width; |
325 | for (yindex = 0; yindex < compptr->MCU_height; yindex++) { |
326 | if (coef->iMCU_row_num < last_iMCU_row || |
327 | yindex + yoffset < compptr->last_row_height) { |
328 | /* Fill in pointers to real blocks in this row */ |
329 | buffer_ptr = buffer[ci][yindex + yoffset] + start_col; |
330 | for (xindex = 0; xindex < blockcnt; xindex++) |
331 | MCU_buffer[blkn++] = buffer_ptr++; |
332 | } else { |
333 | /* At bottom of image, need a whole row of dummy blocks */ |
334 | xindex = 0; |
335 | } |
336 | /* Fill in any dummy blocks needed in this row. |
337 | * Dummy blocks are filled in the same way as in jccoefct.c: |
338 | * all zeroes in the AC entries, DC entries equal to previous |
339 | * block's DC value. The init routine has already zeroed the |
340 | * AC entries, so we need only set the DC entries correctly. |
341 | */ |
342 | for (; xindex < compptr->MCU_width; xindex++) { |
343 | MCU_buffer[blkn] = coef->dummy_buffer[blkn]; |
344 | MCU_buffer[blkn][0][0] = MCU_buffer[blkn - 1][0][0]; |
345 | blkn++; |
346 | } |
347 | } |
348 | } |
349 | /* Try to write the MCU. */ |
350 | if (!(*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { |
351 | /* Suspension forced; update state counters and exit */ |
352 | coef->MCU_vert_offset = yoffset; |
353 | coef->mcu_ctr = MCU_col_num; |
354 | return FALSE; |
355 | } |
356 | } |
357 | /* Completed an MCU row, but perhaps not an iMCU row */ |
358 | coef->mcu_ctr = 0; |
359 | } |
360 | /* Completed the iMCU row, advance counters for next one */ |
361 | coef->iMCU_row_num++; |
362 | start_iMCU_row(cinfo); |
363 | return TRUE; |
364 | } |
365 | |
366 | |
367 | /* |
368 | * Initialize coefficient buffer controller. |
369 | * |
370 | * Each passed coefficient array must be the right size for that |
371 | * coefficient: width_in_blocks wide and height_in_blocks high, |
372 | * with unitheight at least v_samp_factor. |
373 | */ |
374 | |
375 | LOCAL(void) |
376 | transencode_coef_controller(j_compress_ptr cinfo, |
377 | jvirt_barray_ptr *coef_arrays) |
378 | { |
379 | my_coef_ptr coef; |
380 | JBLOCKROW buffer; |
381 | int i; |
382 | |
383 | coef = (my_coef_ptr) |
384 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
385 | sizeof(my_coef_controller)); |
386 | cinfo->coef = (struct jpeg_c_coef_controller *)coef; |
387 | coef->pub.start_pass = start_pass_coef; |
388 | coef->pub.compress_data = compress_output; |
389 | |
390 | /* Save pointer to virtual arrays */ |
391 | coef->whole_image = coef_arrays; |
392 | |
393 | /* Allocate and pre-zero space for dummy DCT blocks. */ |
394 | buffer = (JBLOCKROW) |
395 | (*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
396 | C_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK)); |
397 | jzero_far((void *)buffer, C_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK)); |
398 | for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { |
399 | coef->dummy_buffer[i] = buffer + i; |
400 | } |
401 | } |
402 | |