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