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