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