1 /* 2 * jctrans.c 3 * 4 * Copyright (C) 1995-1998, Thomas G. Lane. 5 * Modified 2000-2017 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 dstinfo->jpeg_width = srcinfo->output_width; 81 dstinfo->jpeg_height = srcinfo->output_height; 82 dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size; 83 dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size; 84 /* Initialize all parameters to default values */ 85 jpeg_set_defaults(dstinfo); 86 /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB. 87 * Fix it to get the right header markers for the image colorspace. 88 * Note: Entropy table assignment in jpeg_set_colorspace 89 * depends on color_transform. 90 * Adaption is also required for setting the appropriate 91 * entropy coding mode dependent on image data precision. 92 */ 93 dstinfo->color_transform = srcinfo->color_transform; 94 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); 95 dstinfo->data_precision = srcinfo->data_precision; 96 dstinfo->arith_code = srcinfo->data_precision > 8 ? TRUE : FALSE; 97 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; 98 /* Copy the source's quantization tables. */ 99 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { 100 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { 101 qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; 102 if (*qtblptr == NULL) 103 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); 104 MEMCOPY((*qtblptr)->quantval, 105 srcinfo->quant_tbl_ptrs[tblno]->quantval, 106 SIZEOF((*qtblptr)->quantval)); 107 (*qtblptr)->sent_table = FALSE; 108 } 109 } 110 /* Copy the source's per-component info. 111 * Note we assume jpeg_set_defaults has allocated the dest comp_info array. 112 */ 113 dstinfo->num_components = srcinfo->num_components; 114 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) 115 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, 116 MAX_COMPONENTS); 117 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; 118 ci < dstinfo->num_components; ci++, incomp++, outcomp++) { 119 outcomp->component_id = incomp->component_id; 120 outcomp->h_samp_factor = incomp->h_samp_factor; 121 outcomp->v_samp_factor = incomp->v_samp_factor; 122 outcomp->quant_tbl_no = incomp->quant_tbl_no; 123 /* Make sure saved quantization table for component matches the qtable 124 * slot. If not, the input file re-used this qtable slot. 125 * IJG encoder currently cannot duplicate this. 126 */ 127 tblno = outcomp->quant_tbl_no; 128 if (tblno < 0 || tblno >= NUM_QUANT_TBLS || 129 srcinfo->quant_tbl_ptrs[tblno] == NULL) 130 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); 131 slot_quant = srcinfo->quant_tbl_ptrs[tblno]; 132 c_quant = incomp->quant_table; 133 if (c_quant != NULL) { 134 for (coefi = 0; coefi < DCTSIZE2; coefi++) { 135 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) 136 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); 137 } 138 } 139 /* Note: we do not copy the source's entropy table assignments; 140 * instead we rely on jpeg_set_colorspace to have made a suitable choice. 141 */ 142 } 143 /* Also copy JFIF version and resolution information, if available. 144 * Strictly speaking this isn't "critical" info, but it's nearly 145 * always appropriate to copy it if available. In particular, 146 * if the application chooses to copy JFIF 1.02 extension markers from 147 * the source file, we need to copy the version to make sure we don't 148 * emit a file that has 1.02 extensions but a claimed version of 1.01. 149 */ 150 if (srcinfo->saw_JFIF_marker) { 151 if (srcinfo->JFIF_major_version == 1 || 152 srcinfo->JFIF_major_version == 2) { 153 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; 154 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; 155 } 156 dstinfo->density_unit = srcinfo->density_unit; 157 dstinfo->X_density = srcinfo->X_density; 158 dstinfo->Y_density = srcinfo->Y_density; 159 } 160 } 161 162 163 LOCAL(void) 164 jpeg_calc_trans_dimensions (j_compress_ptr cinfo) 165 /* Do computations that are needed before master selection phase */ 166 { 167 if (cinfo->min_DCT_h_scaled_size != cinfo->min_DCT_v_scaled_size) 168 ERREXIT2(cinfo, JERR_BAD_DCTSIZE, 169 cinfo->min_DCT_h_scaled_size, cinfo->min_DCT_v_scaled_size); 170 171 cinfo->block_size = cinfo->min_DCT_h_scaled_size; 172 } 173 174 175 /* 176 * Master selection of compression modules for transcoding. 177 * This substitutes for jcinit.c's initialization of the full compressor. 178 */ 179 180 LOCAL(void) 181 transencode_master_selection (j_compress_ptr cinfo, 182 jvirt_barray_ptr * coef_arrays) 183 { 184 /* Do computations that are needed before master selection phase */ 185 jpeg_calc_trans_dimensions(cinfo); 186 187 /* Initialize master control (includes parameter checking/processing) */ 188 jinit_c_master_control(cinfo, TRUE /* transcode only */); 189 190 /* Entropy encoding: either Huffman or arithmetic coding. */ 191 if (cinfo->arith_code) 192 jinit_arith_encoder(cinfo); 193 else { 194 jinit_huff_encoder(cinfo); 195 } 196 197 /* We need a special coefficient buffer controller. */ 198 transencode_coef_controller(cinfo, coef_arrays); 199 200 jinit_marker_writer(cinfo); 201 202 /* We can now tell the memory manager to allocate virtual arrays. */ 203 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 204 205 /* Write the datastream header (SOI, JFIF) immediately. 206 * Frame and scan headers are postponed till later. 207 * This lets application insert special markers after the SOI. 208 */ 209 (*cinfo->marker->write_file_header) (cinfo); 210 } 211 212 213 /* 214 * The rest of this file is a special implementation of the coefficient 215 * buffer controller. This is similar to jccoefct.c, but it handles only 216 * output from presupplied virtual arrays. Furthermore, we generate any 217 * dummy padding blocks on-the-fly rather than expecting them to be present 218 * in the arrays. 219 */ 220 221 /* Private buffer controller object */ 222 223 typedef struct { 224 struct jpeg_c_coef_controller pub; /* public fields */ 225 226 JDIMENSION iMCU_row_num; /* iMCU row # within image */ 227 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ 228 int MCU_vert_offset; /* counts MCU rows within iMCU row */ 229 int MCU_rows_per_iMCU_row; /* number of such rows needed */ 230 231 /* Virtual block array for each component. */ 232 jvirt_barray_ptr * whole_image; 233 234 /* Workspace for constructing dummy blocks at right/bottom edges. */ 235 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; 236 } my_coef_controller; 237 238 typedef my_coef_controller * my_coef_ptr; 239 240 241 LOCAL(void) 242 start_iMCU_row (j_compress_ptr cinfo) 243 /* Reset within-iMCU-row counters for a new row */ 244 { 245 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 246 247 /* In an interleaved scan, an MCU row is the same as an iMCU row. 248 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. 249 * But at the bottom of the image, process only what's left. 250 */ 251 if (cinfo->comps_in_scan > 1) { 252 coef->MCU_rows_per_iMCU_row = 1; 253 } else { 254 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) 255 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; 256 else 257 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; 258 } 259 260 coef->mcu_ctr = 0; 261 coef->MCU_vert_offset = 0; 262 } 263 264 265 /* 266 * Initialize for a processing pass. 267 */ 268 269 METHODDEF(void) 270 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) 271 { 272 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 273 274 if (pass_mode != JBUF_CRANK_DEST) 275 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 276 277 coef->iMCU_row_num = 0; 278 start_iMCU_row(cinfo); 279 } 280 281 282 /* 283 * Process some data. 284 * We process the equivalent of one fully interleaved MCU row ("iMCU" row) 285 * per call, ie, v_samp_factor block rows for each component in the scan. 286 * The data is obtained from the virtual arrays and fed to the entropy coder. 287 * Returns TRUE if the iMCU row is completed, FALSE if suspended. 288 * 289 * NB: input_buf is ignored; it is likely to be a NULL pointer. 290 */ 291 292 METHODDEF(boolean) 293 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) 294 { 295 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 296 JDIMENSION MCU_col_num; /* index of current MCU within row */ 297 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; 298 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 299 int blkn, ci, xindex, yindex, yoffset, blockcnt; 300 JDIMENSION start_col; 301 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 302 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; 303 JBLOCKROW buffer_ptr; 304 jpeg_component_info *compptr; 305 306 /* Align the virtual buffers for the components used in this scan. */ 307 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 308 compptr = cinfo->cur_comp_info[ci]; 309 buffer[ci] = (*cinfo->mem->access_virt_barray) 310 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 311 coef->iMCU_row_num * compptr->v_samp_factor, 312 (JDIMENSION) compptr->v_samp_factor, FALSE); 313 } 314 315 /* Loop to process one whole iMCU row */ 316 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 317 yoffset++) { 318 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; 319 MCU_col_num++) { 320 /* Construct list of pointers to DCT blocks belonging to this MCU */ 321 blkn = 0; /* index of current DCT block within MCU */ 322 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 323 compptr = cinfo->cur_comp_info[ci]; 324 start_col = MCU_col_num * compptr->MCU_width; 325 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width 326 : compptr->last_col_width; 327 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 328 if (coef->iMCU_row_num < last_iMCU_row || 329 yindex+yoffset < compptr->last_row_height) { 330 /* Fill in pointers to real blocks in this row */ 331 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 332 for (xindex = 0; xindex < blockcnt; xindex++) 333 MCU_buffer[blkn++] = buffer_ptr++; 334 } else { 335 /* At bottom of image, need a whole row of dummy blocks */ 336 xindex = 0; 337 } 338 /* Fill in any dummy blocks needed in this row. 339 * Dummy blocks are filled in the same way as in jccoefct.c: 340 * all zeroes in the AC entries, DC entries equal to previous 341 * block's DC value. The init routine has already zeroed the 342 * AC entries, so we need only set the DC entries correctly. 343 */ 344 for (; xindex < compptr->MCU_width; xindex++) { 345 MCU_buffer[blkn] = coef->dummy_buffer[blkn]; 346 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; 347 blkn++; 348 } 349 } 350 } 351 /* Try to write the MCU. */ 352 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { 353 /* Suspension forced; update state counters and exit */ 354 coef->MCU_vert_offset = yoffset; 355 coef->mcu_ctr = MCU_col_num; 356 return FALSE; 357 } 358 } 359 /* Completed an MCU row, but perhaps not an iMCU row */ 360 coef->mcu_ctr = 0; 361 } 362 /* Completed the iMCU row, advance counters for next one */ 363 coef->iMCU_row_num++; 364 start_iMCU_row(cinfo); 365 return TRUE; 366 } 367 368 369 /* 370 * Initialize coefficient buffer controller. 371 * 372 * Each passed coefficient array must be the right size for that 373 * coefficient: width_in_blocks wide and height_in_blocks high, 374 * with unitheight at least v_samp_factor. 375 */ 376 377 LOCAL(void) 378 transencode_coef_controller (j_compress_ptr cinfo, 379 jvirt_barray_ptr * coef_arrays) 380 { 381 my_coef_ptr coef; 382 JBLOCKROW buffer; 383 int i; 384 385 coef = (my_coef_ptr) 386 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 387 SIZEOF(my_coef_controller)); 388 cinfo->coef = &coef->pub; 389 coef->pub.start_pass = start_pass_coef; 390 coef->pub.compress_data = compress_output; 391 392 /* Save pointer to virtual arrays */ 393 coef->whole_image = coef_arrays; 394 395 /* Allocate and pre-zero space for dummy DCT blocks. */ 396 buffer = (JBLOCKROW) 397 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 398 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 399 FMEMZERO((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 400 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { 401 coef->dummy_buffer[i] = buffer + i; 402 } 403 } 404