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| 1 /* |
| 2 * jdmerge.c |
| 3 * |
| 4 * Copyright (C) 1994-1996, Thomas G. Lane. |
| 5 * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB |
| 6 * Copyright (C) 2009, D. R. Commander. |
| 7 * This file is part of the Independent JPEG Group's software. |
| 8 * For conditions of distribution and use, see the accompanying README file. |
| 9 * |
| 10 * This file contains code for merged upsampling/color conversion. |
| 11 * |
| 12 * This file combines functions from jdsample.c and jdcolor.c; |
| 13 * read those files first to understand what's going on. |
| 14 * |
| 15 * When the chroma components are to be upsampled by simple replication |
| 16 * (ie, box filtering), we can save some work in color conversion by |
| 17 * calculating all the output pixels corresponding to a pair of chroma |
| 18 * samples at one time. In the conversion equations |
| 19 * R = Y + K1 * Cr |
| 20 * G = Y + K2 * Cb + K3 * Cr |
| 21 * B = Y + K4 * Cb |
| 22 * only the Y term varies among the group of pixels corresponding to a pair |
| 23 * of chroma samples, so the rest of the terms can be calculated just once. |
| 24 * At typical sampling ratios, this eliminates half or three-quarters of the |
| 25 * multiplications needed for color conversion. |
| 26 * |
| 27 * This file currently provides implementations for the following cases: |
| 28 * YCbCr => RGB color conversion only. |
| 29 * Sampling ratios of 2h1v or 2h2v. |
| 30 * No scaling needed at upsample time. |
| 31 * Corner-aligned (non-CCIR601) sampling alignment. |
| 32 * Other special cases could be added, but in most applications these are |
| 33 * the only common cases. (For uncommon cases we fall back on the more |
| 34 * general code in jdsample.c and jdcolor.c.) |
| 35 */ |
| 36 |
| 37 #define JPEG_INTERNALS |
| 38 #include "jinclude.h" |
| 39 #include "jpeglib.h" |
| 40 #include "jsimd.h" |
| 41 |
| 42 #ifdef UPSAMPLE_MERGING_SUPPORTED |
| 43 |
| 44 |
| 45 /* Private subobject */ |
| 46 |
| 47 typedef struct { |
| 48 struct jpeg_upsampler pub; /* public fields */ |
| 49 |
| 50 /* Pointer to routine to do actual upsampling/conversion of one row group */ |
| 51 JMETHOD(void, upmethod, (j_decompress_ptr cinfo, |
| 52 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, |
| 53 JSAMPARRAY output_buf)); |
| 54 |
| 55 /* Private state for YCC->RGB conversion */ |
| 56 int * Cr_r_tab; /* => table for Cr to R conversion */ |
| 57 int * Cb_b_tab; /* => table for Cb to B conversion */ |
| 58 INT32 * Cr_g_tab; /* => table for Cr to G conversion */ |
| 59 INT32 * Cb_g_tab; /* => table for Cb to G conversion */ |
| 60 |
| 61 /* For 2:1 vertical sampling, we produce two output rows at a time. |
| 62 * We need a "spare" row buffer to hold the second output row if the |
| 63 * application provides just a one-row buffer; we also use the spare |
| 64 * to discard the dummy last row if the image height is odd. |
| 65 */ |
| 66 JSAMPROW spare_row; |
| 67 boolean spare_full; /* T if spare buffer is occupied */ |
| 68 |
| 69 JDIMENSION out_row_width; /* samples per output row */ |
| 70 JDIMENSION rows_to_go; /* counts rows remaining in image */ |
| 71 } my_upsampler; |
| 72 |
| 73 typedef my_upsampler * my_upsample_ptr; |
| 74 |
| 75 #define SCALEBITS 16 /* speediest right-shift on some machines */ |
| 76 #define ONE_HALF ((INT32) 1 << (SCALEBITS-1)) |
| 77 #define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5)) |
| 78 |
| 79 |
| 80 /* |
| 81 * Initialize tables for YCC->RGB colorspace conversion. |
| 82 * This is taken directly from jdcolor.c; see that file for more info. |
| 83 */ |
| 84 |
| 85 LOCAL(void) |
| 86 build_ycc_rgb_table (j_decompress_ptr cinfo) |
| 87 { |
| 88 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 89 int i; |
| 90 INT32 x; |
| 91 SHIFT_TEMPS |
| 92 |
| 93 upsample->Cr_r_tab = (int *) |
| 94 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 95 (MAXJSAMPLE+1) * SIZEOF(int)); |
| 96 upsample->Cb_b_tab = (int *) |
| 97 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 98 (MAXJSAMPLE+1) * SIZEOF(int)); |
| 99 upsample->Cr_g_tab = (INT32 *) |
| 100 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 101 (MAXJSAMPLE+1) * SIZEOF(INT32)); |
| 102 upsample->Cb_g_tab = (INT32 *) |
| 103 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 104 (MAXJSAMPLE+1) * SIZEOF(INT32)); |
| 105 |
| 106 for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) { |
| 107 /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */ |
| 108 /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */ |
| 109 /* Cr=>R value is nearest int to 1.40200 * x */ |
| 110 upsample->Cr_r_tab[i] = (int) |
| 111 RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS); |
| 112 /* Cb=>B value is nearest int to 1.77200 * x */ |
| 113 upsample->Cb_b_tab[i] = (int) |
| 114 RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS); |
| 115 /* Cr=>G value is scaled-up -0.71414 * x */ |
| 116 upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x; |
| 117 /* Cb=>G value is scaled-up -0.34414 * x */ |
| 118 /* We also add in ONE_HALF so that need not do it in inner loop */ |
| 119 upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF; |
| 120 } |
| 121 } |
| 122 |
| 123 |
| 124 /* |
| 125 * Initialize for an upsampling pass. |
| 126 */ |
| 127 |
| 128 METHODDEF(void) |
| 129 start_pass_merged_upsample (j_decompress_ptr cinfo) |
| 130 { |
| 131 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 132 |
| 133 /* Mark the spare buffer empty */ |
| 134 upsample->spare_full = FALSE; |
| 135 /* Initialize total-height counter for detecting bottom of image */ |
| 136 upsample->rows_to_go = cinfo->output_height; |
| 137 } |
| 138 |
| 139 |
| 140 /* |
| 141 * Control routine to do upsampling (and color conversion). |
| 142 * |
| 143 * The control routine just handles the row buffering considerations. |
| 144 */ |
| 145 |
| 146 METHODDEF(void) |
| 147 merged_2v_upsample (j_decompress_ptr cinfo, |
| 148 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
| 149 JDIMENSION in_row_groups_avail, |
| 150 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
| 151 JDIMENSION out_rows_avail) |
| 152 /* 2:1 vertical sampling case: may need a spare row. */ |
| 153 { |
| 154 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 155 JSAMPROW work_ptrs[2]; |
| 156 JDIMENSION num_rows; /* number of rows returned to caller */ |
| 157 |
| 158 if (upsample->spare_full) { |
| 159 /* If we have a spare row saved from a previous cycle, just return it. */ |
| 160 jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0, |
| 161 1, upsample->out_row_width); |
| 162 num_rows = 1; |
| 163 upsample->spare_full = FALSE; |
| 164 } else { |
| 165 /* Figure number of rows to return to caller. */ |
| 166 num_rows = 2; |
| 167 /* Not more than the distance to the end of the image. */ |
| 168 if (num_rows > upsample->rows_to_go) |
| 169 num_rows = upsample->rows_to_go; |
| 170 /* And not more than what the client can accept: */ |
| 171 out_rows_avail -= *out_row_ctr; |
| 172 if (num_rows > out_rows_avail) |
| 173 num_rows = out_rows_avail; |
| 174 /* Create output pointer array for upsampler. */ |
| 175 work_ptrs[0] = output_buf[*out_row_ctr]; |
| 176 if (num_rows > 1) { |
| 177 work_ptrs[1] = output_buf[*out_row_ctr + 1]; |
| 178 } else { |
| 179 work_ptrs[1] = upsample->spare_row; |
| 180 upsample->spare_full = TRUE; |
| 181 } |
| 182 /* Now do the upsampling. */ |
| 183 (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs); |
| 184 } |
| 185 |
| 186 /* Adjust counts */ |
| 187 *out_row_ctr += num_rows; |
| 188 upsample->rows_to_go -= num_rows; |
| 189 /* When the buffer is emptied, declare this input row group consumed */ |
| 190 if (! upsample->spare_full) |
| 191 (*in_row_group_ctr)++; |
| 192 } |
| 193 |
| 194 |
| 195 METHODDEF(void) |
| 196 merged_1v_upsample (j_decompress_ptr cinfo, |
| 197 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
| 198 JDIMENSION in_row_groups_avail, |
| 199 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
| 200 JDIMENSION out_rows_avail) |
| 201 /* 1:1 vertical sampling case: much easier, never need a spare row. */ |
| 202 { |
| 203 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 204 |
| 205 /* Just do the upsampling. */ |
| 206 (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, |
| 207 output_buf + *out_row_ctr); |
| 208 /* Adjust counts */ |
| 209 (*out_row_ctr)++; |
| 210 (*in_row_group_ctr)++; |
| 211 } |
| 212 |
| 213 |
| 214 /* |
| 215 * These are the routines invoked by the control routines to do |
| 216 * the actual upsampling/conversion. One row group is processed per call. |
| 217 * |
| 218 * Note: since we may be writing directly into application-supplied buffers, |
| 219 * we have to be honest about the output width; we can't assume the buffer |
| 220 * has been rounded up to an even width. |
| 221 */ |
| 222 |
| 223 |
| 224 /* |
| 225 * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical. |
| 226 */ |
| 227 |
| 228 METHODDEF(void) |
| 229 h2v1_merged_upsample (j_decompress_ptr cinfo, |
| 230 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, |
| 231 JSAMPARRAY output_buf) |
| 232 { |
| 233 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 234 register int y, cred, cgreen, cblue; |
| 235 int cb, cr; |
| 236 register JSAMPROW outptr; |
| 237 JSAMPROW inptr0, inptr1, inptr2; |
| 238 JDIMENSION col; |
| 239 /* copy these pointers into registers if possible */ |
| 240 register JSAMPLE * range_limit = cinfo->sample_range_limit; |
| 241 int * Crrtab = upsample->Cr_r_tab; |
| 242 int * Cbbtab = upsample->Cb_b_tab; |
| 243 INT32 * Crgtab = upsample->Cr_g_tab; |
| 244 INT32 * Cbgtab = upsample->Cb_g_tab; |
| 245 SHIFT_TEMPS |
| 246 |
| 247 inptr0 = input_buf[0][in_row_group_ctr]; |
| 248 inptr1 = input_buf[1][in_row_group_ctr]; |
| 249 inptr2 = input_buf[2][in_row_group_ctr]; |
| 250 outptr = output_buf[0]; |
| 251 /* Loop for each pair of output pixels */ |
| 252 for (col = cinfo->output_width >> 1; col > 0; col--) { |
| 253 /* Do the chroma part of the calculation */ |
| 254 cb = GETJSAMPLE(*inptr1++); |
| 255 cr = GETJSAMPLE(*inptr2++); |
| 256 cred = Crrtab[cr]; |
| 257 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); |
| 258 cblue = Cbbtab[cb]; |
| 259 /* Fetch 2 Y values and emit 2 pixels */ |
| 260 y = GETJSAMPLE(*inptr0++); |
| 261 outptr[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 262 outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 263 outptr[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 264 outptr += rgb_pixelsize[cinfo->out_color_space]; |
| 265 y = GETJSAMPLE(*inptr0++); |
| 266 outptr[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 267 outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 268 outptr[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 269 outptr += rgb_pixelsize[cinfo->out_color_space]; |
| 270 } |
| 271 /* If image width is odd, do the last output column separately */ |
| 272 if (cinfo->output_width & 1) { |
| 273 cb = GETJSAMPLE(*inptr1); |
| 274 cr = GETJSAMPLE(*inptr2); |
| 275 cred = Crrtab[cr]; |
| 276 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); |
| 277 cblue = Cbbtab[cb]; |
| 278 y = GETJSAMPLE(*inptr0); |
| 279 outptr[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 280 outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 281 outptr[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 282 } |
| 283 } |
| 284 |
| 285 |
| 286 /* |
| 287 * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical. |
| 288 */ |
| 289 |
| 290 METHODDEF(void) |
| 291 h2v2_merged_upsample (j_decompress_ptr cinfo, |
| 292 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, |
| 293 JSAMPARRAY output_buf) |
| 294 { |
| 295 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
| 296 register int y, cred, cgreen, cblue; |
| 297 int cb, cr; |
| 298 register JSAMPROW outptr0, outptr1; |
| 299 JSAMPROW inptr00, inptr01, inptr1, inptr2; |
| 300 JDIMENSION col; |
| 301 /* copy these pointers into registers if possible */ |
| 302 register JSAMPLE * range_limit = cinfo->sample_range_limit; |
| 303 int * Crrtab = upsample->Cr_r_tab; |
| 304 int * Cbbtab = upsample->Cb_b_tab; |
| 305 INT32 * Crgtab = upsample->Cr_g_tab; |
| 306 INT32 * Cbgtab = upsample->Cb_g_tab; |
| 307 SHIFT_TEMPS |
| 308 |
| 309 inptr00 = input_buf[0][in_row_group_ctr*2]; |
| 310 inptr01 = input_buf[0][in_row_group_ctr*2 + 1]; |
| 311 inptr1 = input_buf[1][in_row_group_ctr]; |
| 312 inptr2 = input_buf[2][in_row_group_ctr]; |
| 313 outptr0 = output_buf[0]; |
| 314 outptr1 = output_buf[1]; |
| 315 /* Loop for each group of output pixels */ |
| 316 for (col = cinfo->output_width >> 1; col > 0; col--) { |
| 317 /* Do the chroma part of the calculation */ |
| 318 cb = GETJSAMPLE(*inptr1++); |
| 319 cr = GETJSAMPLE(*inptr2++); |
| 320 cred = Crrtab[cr]; |
| 321 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); |
| 322 cblue = Cbbtab[cb]; |
| 323 /* Fetch 4 Y values and emit 4 pixels */ |
| 324 y = GETJSAMPLE(*inptr00++); |
| 325 outptr0[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 326 outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 327 outptr0[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 328 outptr0 += RGB_PIXELSIZE; |
| 329 y = GETJSAMPLE(*inptr00++); |
| 330 outptr0[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 331 outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 332 outptr0[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 333 outptr0 += RGB_PIXELSIZE; |
| 334 y = GETJSAMPLE(*inptr01++); |
| 335 outptr1[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 336 outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 337 outptr1[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 338 outptr1 += RGB_PIXELSIZE; |
| 339 y = GETJSAMPLE(*inptr01++); |
| 340 outptr1[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 341 outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 342 outptr1[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 343 outptr1 += RGB_PIXELSIZE; |
| 344 } |
| 345 /* If image width is odd, do the last output column separately */ |
| 346 if (cinfo->output_width & 1) { |
| 347 cb = GETJSAMPLE(*inptr1); |
| 348 cr = GETJSAMPLE(*inptr2); |
| 349 cred = Crrtab[cr]; |
| 350 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS); |
| 351 cblue = Cbbtab[cb]; |
| 352 y = GETJSAMPLE(*inptr00); |
| 353 outptr0[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 354 outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 355 outptr0[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 356 y = GETJSAMPLE(*inptr01); |
| 357 outptr1[rgb_red[cinfo->out_color_space]] = range_limit[y + cred]; |
| 358 outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen]; |
| 359 outptr1[rgb_blue[cinfo->out_color_space]] = range_limit[y + cblue]; |
| 360 } |
| 361 } |
| 362 |
| 363 |
| 364 /* |
| 365 * Module initialization routine for merged upsampling/color conversion. |
| 366 * |
| 367 * NB: this is called under the conditions determined by use_merged_upsample() |
| 368 * in jdmaster.c. That routine MUST correspond to the actual capabilities |
| 369 * of this module; no safety checks are made here. |
| 370 */ |
| 371 |
| 372 GLOBAL(void) |
| 373 jinit_merged_upsampler (j_decompress_ptr cinfo) |
| 374 { |
| 375 my_upsample_ptr upsample; |
| 376 |
| 377 upsample = (my_upsample_ptr) |
| 378 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 379 SIZEOF(my_upsampler)); |
| 380 cinfo->upsample = (struct jpeg_upsampler *) upsample; |
| 381 upsample->pub.start_pass = start_pass_merged_upsample; |
| 382 upsample->pub.need_context_rows = FALSE; |
| 383 |
| 384 upsample->out_row_width = cinfo->output_width * cinfo->out_color_components; |
| 385 |
| 386 if (cinfo->max_v_samp_factor == 2) { |
| 387 upsample->pub.upsample = merged_2v_upsample; |
| 388 if (jsimd_can_h2v2_merged_upsample()) |
| 389 upsample->upmethod = jsimd_h2v2_merged_upsample; |
| 390 else |
| 391 upsample->upmethod = h2v2_merged_upsample; |
| 392 /* Allocate a spare row buffer */ |
| 393 upsample->spare_row = (JSAMPROW) |
| 394 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 395 (size_t) (upsample->out_row_width * SIZEOF(JSAMPLE))); |
| 396 } else { |
| 397 upsample->pub.upsample = merged_1v_upsample; |
| 398 if (jsimd_can_h2v1_merged_upsample()) |
| 399 upsample->upmethod = jsimd_h2v1_merged_upsample; |
| 400 else |
| 401 upsample->upmethod = h2v1_merged_upsample; |
| 402 /* No spare row needed */ |
| 403 upsample->spare_row = NULL; |
| 404 } |
| 405 |
| 406 build_ycc_rgb_table(cinfo); |
| 407 } |
| 408 |
| 409 #endif /* UPSAMPLE_MERGING_SUPPORTED */ |
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