1 /* 2 * jctrans.c 3 * 4 * Copyright (C) 1995-1998, Thomas G. Lane. 5 * Modified 2000-2012 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 depends 89 * on color_transform. 90 */ 91 dstinfo->color_transform = srcinfo->color_transform; 92 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); 93 dstinfo->data_precision = srcinfo->data_precision; 94 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; 95 /* Copy the source's quantization tables. */ 96 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { 97 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { 98 qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; 99 if (*qtblptr == NULL) 100 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); 101 MEMCOPY((*qtblptr)->quantval, 102 srcinfo->quant_tbl_ptrs[tblno]->quantval, 103 SIZEOF((*qtblptr)->quantval)); 104 (*qtblptr)->sent_table = FALSE; 105 } 106 } 107 /* Copy the source's per-component info. 108 * Note we assume jpeg_set_defaults has allocated the dest comp_info array. 109 */ 110 dstinfo->num_components = srcinfo->num_components; 111 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) 112 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, 113 MAX_COMPONENTS); 114 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; 115 ci < dstinfo->num_components; ci++, incomp++, outcomp++) { 116 outcomp->component_id = incomp->component_id; 117 outcomp->h_samp_factor = incomp->h_samp_factor; 118 outcomp->v_samp_factor = incomp->v_samp_factor; 119 outcomp->quant_tbl_no = incomp->quant_tbl_no; 120 /* Make sure saved quantization table for component matches the qtable 121 * slot. If not, the input file re-used this qtable slot. 122 * IJG encoder currently cannot duplicate this. 123 */ 124 tblno = outcomp->quant_tbl_no; 125 if (tblno < 0 || tblno >= NUM_QUANT_TBLS || 126 srcinfo->quant_tbl_ptrs[tblno] == NULL) 127 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); 128 slot_quant = srcinfo->quant_tbl_ptrs[tblno]; 129 c_quant = incomp->quant_table; 130 if (c_quant != NULL) { 131 for (coefi = 0; coefi < DCTSIZE2; coefi++) { 132 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) 133 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); 134 } 135 } 136 /* Note: we do not copy the source's entropy table assignments; 137 * instead we rely on jpeg_set_colorspace to have made a suitable choice. 138 */ 139 } 140 /* Also copy JFIF version and resolution information, if available. 141 * Strictly speaking this isn't "critical" info, but it's nearly 142 * always appropriate to copy it if available. In particular, 143 * if the application chooses to copy JFIF 1.02 extension markers from 144 * the source file, we need to copy the version to make sure we don't 145 * emit a file that has 1.02 extensions but a claimed version of 1.01. 146 * We will *not*, however, copy version info from mislabeled "2.01" files. 147 */ 148 if (srcinfo->saw_JFIF_marker) { 149 if (srcinfo->JFIF_major_version == 1) { 150 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; 151 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; 152 } 153 dstinfo->density_unit = srcinfo->density_unit; 154 dstinfo->X_density = srcinfo->X_density; 155 dstinfo->Y_density = srcinfo->Y_density; 156 } 157 } 158 159 160 /* 161 * Master selection of compression modules for transcoding. 162 * This substitutes for jcinit.c's initialization of the full compressor. 163 */ 164 165 LOCAL(void) 166 transencode_master_selection (j_compress_ptr cinfo, 167 jvirt_barray_ptr * coef_arrays) 168 { 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 jinit_arith_encoder(cinfo); 175 else { 176 jinit_huff_encoder(cinfo); 177 } 178 179 /* We need a special coefficient buffer controller. */ 180 transencode_coef_controller(cinfo, coef_arrays); 181 182 jinit_marker_writer(cinfo); 183 184 /* We can now tell the memory manager to allocate virtual arrays. */ 185 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 186 187 /* Write the datastream header (SOI, JFIF) immediately. 188 * Frame and scan headers are postponed till later. 189 * This lets application insert special markers after the SOI. 190 */ 191 (*cinfo->marker->write_file_header) (cinfo); 192 } 193 194 195 /* 196 * The rest of this file is a special implementation of the coefficient 197 * buffer controller. This is similar to jccoefct.c, but it handles only 198 * output from presupplied virtual arrays. Furthermore, we generate any 199 * dummy padding blocks on-the-fly rather than expecting them to be present 200 * in the arrays. 201 */ 202 203 /* Private buffer controller object */ 204 205 typedef struct { 206 struct jpeg_c_coef_controller pub; /* public fields */ 207 208 JDIMENSION iMCU_row_num; /* iMCU row # within image */ 209 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ 210 int MCU_vert_offset; /* counts MCU rows within iMCU row */ 211 int MCU_rows_per_iMCU_row; /* number of such rows needed */ 212 213 /* Virtual block array for each component. */ 214 jvirt_barray_ptr * whole_image; 215 216 /* Workspace for constructing dummy blocks at right/bottom edges. */ 217 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; 218 } my_coef_controller; 219 220 typedef my_coef_controller * my_coef_ptr; 221 222 223 LOCAL(void) 224 start_iMCU_row (j_compress_ptr cinfo) 225 /* Reset within-iMCU-row counters for a new row */ 226 { 227 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 228 229 /* In an interleaved scan, an MCU row is the same as an iMCU row. 230 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. 231 * But at the bottom of the image, process only what's left. 232 */ 233 if (cinfo->comps_in_scan > 1) { 234 coef->MCU_rows_per_iMCU_row = 1; 235 } else { 236 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) 237 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; 238 else 239 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; 240 } 241 242 coef->mcu_ctr = 0; 243 coef->MCU_vert_offset = 0; 244 } 245 246 247 /* 248 * Initialize for a processing pass. 249 */ 250 251 METHODDEF(void) 252 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) 253 { 254 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 255 256 if (pass_mode != JBUF_CRANK_DEST) 257 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 258 259 coef->iMCU_row_num = 0; 260 start_iMCU_row(cinfo); 261 } 262 263 264 /* 265 * Process some data. 266 * We process the equivalent of one fully interleaved MCU row ("iMCU" row) 267 * per call, ie, v_samp_factor block rows for each component in the scan. 268 * The data is obtained from the virtual arrays and fed to the entropy coder. 269 * Returns TRUE if the iMCU row is completed, FALSE if suspended. 270 * 271 * NB: input_buf is ignored; it is likely to be a NULL pointer. 272 */ 273 274 METHODDEF(boolean) 275 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) 276 { 277 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 278 JDIMENSION MCU_col_num; /* index of current MCU within row */ 279 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; 280 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 281 int blkn, ci, xindex, yindex, yoffset, blockcnt; 282 JDIMENSION start_col; 283 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 284 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; 285 JBLOCKROW buffer_ptr; 286 jpeg_component_info *compptr; 287 288 /* Align the virtual buffers for the components used in this scan. */ 289 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 290 compptr = cinfo->cur_comp_info[ci]; 291 buffer[ci] = (*cinfo->mem->access_virt_barray) 292 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 293 coef->iMCU_row_num * compptr->v_samp_factor, 294 (JDIMENSION) compptr->v_samp_factor, FALSE); 295 } 296 297 /* Loop to process one whole iMCU row */ 298 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 299 yoffset++) { 300 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; 301 MCU_col_num++) { 302 /* Construct list of pointers to DCT blocks belonging to this MCU */ 303 blkn = 0; /* index of current DCT block within MCU */ 304 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 305 compptr = cinfo->cur_comp_info[ci]; 306 start_col = MCU_col_num * compptr->MCU_width; 307 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width 308 : compptr->last_col_width; 309 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 310 if (coef->iMCU_row_num < last_iMCU_row || 311 yindex+yoffset < compptr->last_row_height) { 312 /* Fill in pointers to real blocks in this row */ 313 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 314 for (xindex = 0; xindex < blockcnt; xindex++) 315 MCU_buffer[blkn++] = buffer_ptr++; 316 } else { 317 /* At bottom of image, need a whole row of dummy blocks */ 318 xindex = 0; 319 } 320 /* Fill in any dummy blocks needed in this row. 321 * Dummy blocks are filled in the same way as in jccoefct.c: 322 * all zeroes in the AC entries, DC entries equal to previous 323 * block's DC value. The init routine has already zeroed the 324 * AC entries, so we need only set the DC entries correctly. 325 */ 326 for (; xindex < compptr->MCU_width; xindex++) { 327 MCU_buffer[blkn] = coef->dummy_buffer[blkn]; 328 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; 329 blkn++; 330 } 331 } 332 } 333 /* Try to write the MCU. */ 334 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { 335 /* Suspension forced; update state counters and exit */ 336 coef->MCU_vert_offset = yoffset; 337 coef->mcu_ctr = MCU_col_num; 338 return FALSE; 339 } 340 } 341 /* Completed an MCU row, but perhaps not an iMCU row */ 342 coef->mcu_ctr = 0; 343 } 344 /* Completed the iMCU row, advance counters for next one */ 345 coef->iMCU_row_num++; 346 start_iMCU_row(cinfo); 347 return TRUE; 348 } 349 350 351 /* 352 * Initialize coefficient buffer controller. 353 * 354 * Each passed coefficient array must be the right size for that 355 * coefficient: width_in_blocks wide and height_in_blocks high, 356 * with unitheight at least v_samp_factor. 357 */ 358 359 LOCAL(void) 360 transencode_coef_controller (j_compress_ptr cinfo, 361 jvirt_barray_ptr * coef_arrays) 362 { 363 my_coef_ptr coef; 364 JBLOCKROW buffer; 365 int i; 366 367 coef = (my_coef_ptr) 368 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 369 SIZEOF(my_coef_controller)); 370 cinfo->coef = &coef->pub; 371 coef->pub.start_pass = start_pass_coef; 372 coef->pub.compress_data = compress_output; 373 374 /* Save pointer to virtual arrays */ 375 coef->whole_image = coef_arrays; 376 377 /* Allocate and pre-zero space for dummy DCT blocks. */ 378 buffer = (JBLOCKROW) 379 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 380 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 381 FMEMZERO((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 382 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { 383 coef->dummy_buffer[i] = buffer + i; 384 } 385 } 386
