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 */ 20LOCAL(void) transencode_master_selection 21 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); 22LOCAL(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 38GLOBAL(void) 39jpeg_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 63GLOBAL(void) 64jpeg_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 */ 89 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); 90 dstinfo->data_precision = srcinfo->data_precision; 91 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; 92 /* Copy the source's quantization tables. */ 93 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { 94 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { 95 qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; 96 if (*qtblptr == NULL) 97 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); 98 MEMCOPY((*qtblptr)->quantval, 99 srcinfo->quant_tbl_ptrs[tblno]->quantval, 100 SIZEOF((*qtblptr)->quantval)); 101 (*qtblptr)->sent_table = FALSE; 102 } 103 } 104 /* Copy the source's per-component info. 105 * Note we assume jpeg_set_defaults has allocated the dest comp_info array. 106 */ 107 dstinfo->num_components = srcinfo->num_components; 108 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) 109 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, 110 MAX_COMPONENTS); 111 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; 112 ci < dstinfo->num_components; ci++, incomp++, outcomp++) { 113 outcomp->component_id = incomp->component_id; 114 outcomp->h_samp_factor = incomp->h_samp_factor; 115 outcomp->v_samp_factor = incomp->v_samp_factor; 116 outcomp->quant_tbl_no = incomp->quant_tbl_no; 117 /* Make sure saved quantization table for component matches the qtable 118 * slot. If not, the input file re-used this qtable slot. 119 * IJG encoder currently cannot duplicate this. 120 */ 121 tblno = outcomp->quant_tbl_no; 122 if (tblno < 0 || tblno >= NUM_QUANT_TBLS || 123 srcinfo->quant_tbl_ptrs[tblno] == NULL) 124 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); 125 slot_quant = srcinfo->quant_tbl_ptrs[tblno]; 126 c_quant = incomp->quant_table; 127 if (c_quant != NULL) { 128 for (coefi = 0; coefi < DCTSIZE2; coefi++) { 129 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) 130 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); 131 } 132 } 133 /* Note: we do not copy the source's Huffman table assignments; 134 * instead we rely on jpeg_set_colorspace to have made a suitable choice. 135 */ 136 } 137 /* Also copy JFIF version and resolution information, if available. 138 * Strictly speaking this isn't "critical" info, but it's nearly 139 * always appropriate to copy it if available. In particular, 140 * if the application chooses to copy JFIF 1.02 extension markers from 141 * the source file, we need to copy the version to make sure we don't 142 * emit a file that has 1.02 extensions but a claimed version of 1.01. 143 * We will *not*, however, copy version info from mislabeled "2.01" files. 144 */ 145 if (srcinfo->saw_JFIF_marker) { 146 if (srcinfo->JFIF_major_version == 1) { 147 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; 148 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; 149 } 150 dstinfo->density_unit = srcinfo->density_unit; 151 dstinfo->X_density = srcinfo->X_density; 152 dstinfo->Y_density = srcinfo->Y_density; 153 } 154} 155 156 157/* 158 * Master selection of compression modules for transcoding. 159 * This substitutes for jcinit.c's initialization of the full compressor. 160 */ 161 162LOCAL(void) 163transencode_master_selection (j_compress_ptr cinfo, 164 jvirt_barray_ptr * coef_arrays) 165{ 166 /* Initialize master control (includes parameter checking/processing) */ 167 jinit_c_master_control(cinfo, TRUE /* transcode only */); 168 169 /* Entropy encoding: either Huffman or arithmetic coding. */ 170 if (cinfo->arith_code) 171 jinit_arith_encoder(cinfo); 172 else { 173 jinit_huff_encoder(cinfo); 174 } 175 176 /* We need a special coefficient buffer controller. */ 177 transencode_coef_controller(cinfo, coef_arrays); 178 179 jinit_marker_writer(cinfo); 180 181 /* We can now tell the memory manager to allocate virtual arrays. */ 182 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 183 184 /* Write the datastream header (SOI, JFIF) immediately. 185 * Frame and scan headers are postponed till later. 186 * This lets application insert special markers after the SOI. 187 */ 188 (*cinfo->marker->write_file_header) (cinfo); 189} 190 191 192/* 193 * The rest of this file is a special implementation of the coefficient 194 * buffer controller. This is similar to jccoefct.c, but it handles only 195 * output from presupplied virtual arrays. Furthermore, we generate any 196 * dummy padding blocks on-the-fly rather than expecting them to be present 197 * in the arrays. 198 */ 199 200/* Private buffer controller object */ 201 202typedef struct { 203 struct jpeg_c_coef_controller pub; /* public fields */ 204 205 JDIMENSION iMCU_row_num; /* iMCU row # within image */ 206 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ 207 int MCU_vert_offset; /* counts MCU rows within iMCU row */ 208 int MCU_rows_per_iMCU_row; /* number of such rows needed */ 209 210 /* Virtual block array for each component. */ 211 jvirt_barray_ptr * whole_image; 212 213 /* Workspace for constructing dummy blocks at right/bottom edges. */ 214 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; 215} my_coef_controller; 216 217typedef my_coef_controller * my_coef_ptr; 218 219 220LOCAL(void) 221start_iMCU_row (j_compress_ptr cinfo) 222/* Reset within-iMCU-row counters for a new row */ 223{ 224 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 225 226 /* In an interleaved scan, an MCU row is the same as an iMCU row. 227 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. 228 * But at the bottom of the image, process only what's left. 229 */ 230 if (cinfo->comps_in_scan > 1) { 231 coef->MCU_rows_per_iMCU_row = 1; 232 } else { 233 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) 234 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; 235 else 236 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; 237 } 238 239 coef->mcu_ctr = 0; 240 coef->MCU_vert_offset = 0; 241} 242 243 244/* 245 * Initialize for a processing pass. 246 */ 247 248METHODDEF(void) 249start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) 250{ 251 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 252 253 if (pass_mode != JBUF_CRANK_DEST) 254 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 255 256 coef->iMCU_row_num = 0; 257 start_iMCU_row(cinfo); 258} 259 260 261/* 262 * Process some data. 263 * We process the equivalent of one fully interleaved MCU row ("iMCU" row) 264 * per call, ie, v_samp_factor block rows for each component in the scan. 265 * The data is obtained from the virtual arrays and fed to the entropy coder. 266 * Returns TRUE if the iMCU row is completed, FALSE if suspended. 267 * 268 * NB: input_buf is ignored; it is likely to be a NULL pointer. 269 */ 270 271METHODDEF(boolean) 272compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) 273{ 274 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 275 JDIMENSION MCU_col_num; /* index of current MCU within row */ 276 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; 277 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 278 int blkn, ci, xindex, yindex, yoffset, blockcnt; 279 JDIMENSION start_col; 280 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 281 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; 282 JBLOCKROW buffer_ptr; 283 jpeg_component_info *compptr; 284 285 /* Align the virtual buffers for the components used in this scan. */ 286 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 287 compptr = cinfo->cur_comp_info[ci]; 288 buffer[ci] = (*cinfo->mem->access_virt_barray) 289 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 290 coef->iMCU_row_num * compptr->v_samp_factor, 291 (JDIMENSION) compptr->v_samp_factor, FALSE); 292 } 293 294 /* Loop to process one whole iMCU row */ 295 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 296 yoffset++) { 297 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; 298 MCU_col_num++) { 299 /* Construct list of pointers to DCT blocks belonging to this MCU */ 300 blkn = 0; /* index of current DCT block within MCU */ 301 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 302 compptr = cinfo->cur_comp_info[ci]; 303 start_col = MCU_col_num * compptr->MCU_width; 304 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width 305 : compptr->last_col_width; 306 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 307 if (coef->iMCU_row_num < last_iMCU_row || 308 yindex+yoffset < compptr->last_row_height) { 309 /* Fill in pointers to real blocks in this row */ 310 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 311 for (xindex = 0; xindex < blockcnt; xindex++) 312 MCU_buffer[blkn++] = buffer_ptr++; 313 } else { 314 /* At bottom of image, need a whole row of dummy blocks */ 315 xindex = 0; 316 } 317 /* Fill in any dummy blocks needed in this row. 318 * Dummy blocks are filled in the same way as in jccoefct.c: 319 * all zeroes in the AC entries, DC entries equal to previous 320 * block's DC value. The init routine has already zeroed the 321 * AC entries, so we need only set the DC entries correctly. 322 */ 323 for (; xindex < compptr->MCU_width; xindex++) { 324 MCU_buffer[blkn] = coef->dummy_buffer[blkn]; 325 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; 326 blkn++; 327 } 328 } 329 } 330 /* Try to write the MCU. */ 331 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { 332 /* Suspension forced; update state counters and exit */ 333 coef->MCU_vert_offset = yoffset; 334 coef->mcu_ctr = MCU_col_num; 335 return FALSE; 336 } 337 } 338 /* Completed an MCU row, but perhaps not an iMCU row */ 339 coef->mcu_ctr = 0; 340 } 341 /* Completed the iMCU row, advance counters for next one */ 342 coef->iMCU_row_num++; 343 start_iMCU_row(cinfo); 344 return TRUE; 345} 346 347 348/* 349 * Initialize coefficient buffer controller. 350 * 351 * Each passed coefficient array must be the right size for that 352 * coefficient: width_in_blocks wide and height_in_blocks high, 353 * with unitheight at least v_samp_factor. 354 */ 355 356LOCAL(void) 357transencode_coef_controller (j_compress_ptr cinfo, 358 jvirt_barray_ptr * coef_arrays) 359{ 360 my_coef_ptr coef; 361 JBLOCKROW buffer; 362 int i; 363 364 coef = (my_coef_ptr) 365 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 366 SIZEOF(my_coef_controller)); 367 cinfo->coef = (struct jpeg_c_coef_controller *) coef; 368 coef->pub.start_pass = start_pass_coef; 369 coef->pub.compress_data = compress_output; 370 371 /* Save pointer to virtual arrays */ 372 coef->whole_image = coef_arrays; 373 374 /* Allocate and pre-zero space for dummy DCT blocks. */ 375 buffer = (JBLOCKROW) 376 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 377 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 378 jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 379 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { 380 coef->dummy_buffer[i] = buffer + i; 381 } 382} 383