media/libjpeg/jctrans.c

   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 }