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 */
19LOCAL(void) transencode_master_selection
20 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
21LOCAL(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
37GLOBAL(void)
38jpeg_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
62GLOBAL(void)
63jpeg_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
157LOCAL(void)
158transencode_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
208typedef 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
223typedef my_coef_controller * my_coef_ptr;
224
225
226LOCAL(void)
227start_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
254METHODDEF(void)
255start_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
277METHODDEF(boolean)
278compress_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
362LOCAL(void)
363transencode_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}
389