jctrans.c 15 KB

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