1 /*
2 * jdmerge.c
3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains code for merged upsampling/color conversion.
9 *
10 * This file combines functions from jdsample.c and jdcolor.c;
11 * read those files first to understand what's going on.
12 *
13 * When the chroma components are to be upsampled by simple replication
14 * (ie, box filtering), we can save some work in color conversion by
15 * calculating all the output pixels corresponding to a pair of chroma
16 * samples at one time. In the conversion equations
17 * R = Y + K1 * Cr
18 * G = Y + K2 * Cb + K3 * Cr
19 * B = Y + K4 * Cb
20 * only the Y term varies among the group of pixels corresponding to a pair
21 * of chroma samples, so the rest of the terms can be calculated just once.
22 * At typical sampling ratios, this eliminates half or three-quarters of the
23 * multiplications needed for color conversion.
24 *
25 * This file currently provides implementations for the following cases:
26 * YCbCr => RGB color conversion only.
27 * Sampling ratios of 2h1v or 2h2v.
28 * No scaling needed at upsample time.
29 * Corner-aligned (non-CCIR601) sampling alignment.
30 * Other special cases could be added, but in most applications these are
31 * the only common cases. (For uncommon cases we fall back on the more
32 * general code in jdsample.c and jdcolor.c.)
33 */
34
35 #define JPEG_INTERNALS
36 #include "dcmtk/config/osconfig.h"
37 #include "jinclude16.h"
38 #include "jpeglib16.h"
39
40 /* check if we have a 64-bit integer type */
41 #if SIZEOF_LONG == 8
42 typedef long jdmerge_sint64;
43 #elif defined(_WIN32)
44 typedef __int64 jdmerge_sint64;
45 #elif defined(HAVE_LONG_LONG)
46 typedef long long jdmerge_sint64;
47 #elif defined (HAVE_LONGLONG)
48 typedef longlong jdmerge_sint64;
49 #else
50 #define JDMERGE_NO_SINT64
51 #endif
52
53 #ifdef UPSAMPLE_MERGING_SUPPORTED
54
55
56 /* Private subobject */
57
58 typedef struct {
59 struct jpeg_upsampler pub; /* public fields */
60
61 /* Pointer to routine to do actual upsampling/conversion of one row group */
62 JMETHOD(void, upmethod, (j_decompress_ptr cinfo,
63 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
64 JSAMPARRAY output_buf));
65
66 /* Private state for YCC->RGB conversion */
67 int * Cr_r_tab; /* => table for Cr to R conversion */
68 int * Cb_b_tab; /* => table for Cb to B conversion */
69 IJG_INT32 * Cr_g_tab; /* => table for Cr to G conversion */
70 IJG_INT32 * Cb_g_tab; /* => table for Cb to G conversion */
71
72 /* For 2:1 vertical sampling, we produce two output rows at a time.
73 * We need a "spare" row buffer to hold the second output row if the
74 * application provides just a one-row buffer; we also use the spare
75 * to discard the dummy last row if the image height is odd.
76 */
77 JSAMPROW spare_row;
78 boolean spare_full; /* T if spare buffer is occupied */
79
80 JDIMENSION out_row_width; /* samples per output row */
81 JDIMENSION rows_to_go; /* counts rows remaining in image */
82 } my_upsampler;
83
84 typedef my_upsampler * my_upsample_ptr;
85
86 #define SCALEBITS 16 /* speediest right-shift on some machines */
87 #define ONE_HALF ((IJG_INT32) 1 << (SCALEBITS-1))
88 #define FIX(x) ((IJG_INT32) ((x) * (1L<<SCALEBITS) + 0.5))
89
90
91 /*
92 * Initialize tables for YCC->RGB colorspace conversion.
93 * This is taken directly from jdcolor.c; see that file for more info.
94 */
95
96 LOCAL(void)
build_ycc_rgb_table(j_decompress_ptr cinfo)97 build_ycc_rgb_table (j_decompress_ptr cinfo)
98 {
99 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
100 int i;
101 IJG_INT32 x;
102 SHIFT_TEMPS
103
104 upsample->Cr_r_tab = (int *)
105 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
106 (MAXJSAMPLE+1) * SIZEOF(int));
107 upsample->Cb_b_tab = (int *)
108 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
109 (MAXJSAMPLE+1) * SIZEOF(int));
110 upsample->Cr_g_tab = (IJG_INT32 *)
111 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
112 (MAXJSAMPLE+1) * SIZEOF(IJG_INT32));
113 upsample->Cb_g_tab = (IJG_INT32 *)
114 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
115 (MAXJSAMPLE+1) * SIZEOF(IJG_INT32));
116
117 for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
118 /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
119 /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
120 #ifdef JDMERGE_NO_SINT64
121 /* Cr=>R value is nearest int to 1.40200 * x */
122 upsample->Cr_r_tab[i] = (int)
123 RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
124 /* Cb=>B value is nearest int to 1.77200 * x */
125 upsample->Cb_b_tab[i] = (int)
126 RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
127 #else
128 /* Cr=>R value is nearest int to 1.40200 * x */
129 upsample->Cr_r_tab[i] = (int)
130 RIGHT_SHIFT((jdmerge_sint64) FIX(1.40200) * x + ONE_HALF, SCALEBITS);
131 /* Cb=>B value is nearest int to 1.77200 * x */
132 upsample->Cb_b_tab[i] = (int)
133 RIGHT_SHIFT((jdmerge_sint64) FIX(1.77200) * x + ONE_HALF, SCALEBITS);
134 #endif
135 /* Cr=>G value is scaled-up -0.71414 * x */
136 upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x;
137 /* Cb=>G value is scaled-up -0.34414 * x */
138 /* We also add in ONE_HALF so that need not do it in inner loop */
139 upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
140 }
141 }
142
143
144 /*
145 * Initialize for an upsampling pass.
146 */
147
148 METHODDEF(void)
start_pass_merged_upsample(j_decompress_ptr cinfo)149 start_pass_merged_upsample (j_decompress_ptr cinfo)
150 {
151 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
152
153 /* Mark the spare buffer empty */
154 upsample->spare_full = FALSE;
155 /* Initialize total-height counter for detecting bottom of image */
156 upsample->rows_to_go = cinfo->output_height;
157 }
158
159
160 /*
161 * Control routine to do upsampling (and color conversion).
162 *
163 * The control routine just handles the row buffering considerations.
164 */
165
166 METHODDEF(void)
merged_2v_upsample(j_decompress_ptr cinfo,JSAMPIMAGE input_buf,JDIMENSION * in_row_group_ctr,JDIMENSION in_row_groups_avail,JSAMPARRAY output_buf,JDIMENSION * out_row_ctr,JDIMENSION out_rows_avail)167 merged_2v_upsample (j_decompress_ptr cinfo,
168 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
169 JDIMENSION in_row_groups_avail,
170 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
171 JDIMENSION out_rows_avail)
172 /* 2:1 vertical sampling case: may need a spare row. */
173 {
174 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
175 JSAMPROW work_ptrs[2];
176 JDIMENSION num_rows; /* number of rows returned to caller */
177
178 if (upsample->spare_full) {
179 /* If we have a spare row saved from a previous cycle, just return it. */
180 jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0,
181 1, upsample->out_row_width);
182 num_rows = 1;
183 upsample->spare_full = FALSE;
184 } else {
185 /* Figure number of rows to return to caller. */
186 num_rows = 2;
187 /* Not more than the distance to the end of the image. */
188 if (num_rows > upsample->rows_to_go)
189 num_rows = upsample->rows_to_go;
190 /* And not more than what the client can accept: */
191 out_rows_avail -= *out_row_ctr;
192 if (num_rows > out_rows_avail)
193 num_rows = out_rows_avail;
194 /* Create output pointer array for upsampler. */
195 work_ptrs[0] = output_buf[*out_row_ctr];
196 if (num_rows > 1) {
197 work_ptrs[1] = output_buf[*out_row_ctr + 1];
198 } else {
199 work_ptrs[1] = upsample->spare_row;
200 upsample->spare_full = TRUE;
201 }
202 /* Now do the upsampling. */
203 (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs);
204 }
205
206 /* Adjust counts */
207 *out_row_ctr += num_rows;
208 upsample->rows_to_go -= num_rows;
209 /* When the buffer is emptied, declare this input row group consumed */
210 if (! upsample->spare_full)
211 (*in_row_group_ctr)++;
212 }
213
214
215 METHODDEF(void)
merged_1v_upsample(j_decompress_ptr cinfo,JSAMPIMAGE input_buf,JDIMENSION * in_row_group_ctr,JDIMENSION in_row_groups_avail,JSAMPARRAY output_buf,JDIMENSION * out_row_ctr,JDIMENSION out_rows_avail)216 merged_1v_upsample (j_decompress_ptr cinfo,
217 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
218 JDIMENSION in_row_groups_avail,
219 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
220 JDIMENSION out_rows_avail)
221 /* 1:1 vertical sampling case: much easier, never need a spare row. */
222 {
223 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
224
225 /* Just do the upsampling. */
226 (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr,
227 output_buf + *out_row_ctr);
228 /* Adjust counts */
229 (*out_row_ctr)++;
230 (*in_row_group_ctr)++;
231 }
232
233
234 /*
235 * These are the routines invoked by the control routines to do
236 * the actual upsampling/conversion. One row group is processed per call.
237 *
238 * Note: since we may be writing directly into application-supplied buffers,
239 * we have to be honest about the output width; we can't assume the buffer
240 * has been rounded up to an even width.
241 */
242
243
244 /*
245 * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
246 */
247
248 METHODDEF(void)
h2v1_merged_upsample(j_decompress_ptr cinfo,JSAMPIMAGE input_buf,JDIMENSION in_row_group_ctr,JSAMPARRAY output_buf)249 h2v1_merged_upsample (j_decompress_ptr cinfo,
250 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
251 JSAMPARRAY output_buf)
252 {
253 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
254 register int y, cred, cgreen, cblue;
255 int cb, cr;
256 register JSAMPROW outptr;
257 JSAMPROW inptr0, inptr1, inptr2;
258 JDIMENSION col;
259 /* copy these pointers into registers if possible */
260 register JSAMPLE * range_limit = cinfo->sample_range_limit;
261 int * Crrtab = upsample->Cr_r_tab;
262 int * Cbbtab = upsample->Cb_b_tab;
263 IJG_INT32 * Crgtab = upsample->Cr_g_tab;
264 IJG_INT32 * Cbgtab = upsample->Cb_g_tab;
265 SHIFT_TEMPS
266
267 inptr0 = input_buf[0][in_row_group_ctr];
268 inptr1 = input_buf[1][in_row_group_ctr];
269 inptr2 = input_buf[2][in_row_group_ctr];
270 outptr = output_buf[0];
271 /* Loop for each pair of output pixels */
272 for (col = cinfo->output_width >> 1; col > 0; col--) {
273 /* Do the chroma part of the calculation */
274 cb = GETJSAMPLE(*inptr1++);
275 cr = GETJSAMPLE(*inptr2++);
276 cred = Crrtab[cr];
277 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
278 cblue = Cbbtab[cb];
279 /* Fetch 2 Y values and emit 2 pixels */
280 y = GETJSAMPLE(*inptr0++);
281 outptr[RGB_RED] = range_limit[y + cred];
282 outptr[RGB_GREEN] = range_limit[y + cgreen];
283 outptr[RGB_BLUE] = range_limit[y + cblue];
284 outptr += RGB_PIXELSIZE;
285 y = GETJSAMPLE(*inptr0++);
286 outptr[RGB_RED] = range_limit[y + cred];
287 outptr[RGB_GREEN] = range_limit[y + cgreen];
288 outptr[RGB_BLUE] = range_limit[y + cblue];
289 outptr += RGB_PIXELSIZE;
290 }
291 /* If image width is odd, do the last output column separately */
292 if (cinfo->output_width & 1) {
293 cb = GETJSAMPLE(*inptr1);
294 cr = GETJSAMPLE(*inptr2);
295 cred = Crrtab[cr];
296 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
297 cblue = Cbbtab[cb];
298 y = GETJSAMPLE(*inptr0);
299 outptr[RGB_RED] = range_limit[y + cred];
300 outptr[RGB_GREEN] = range_limit[y + cgreen];
301 outptr[RGB_BLUE] = range_limit[y + cblue];
302 }
303 }
304
305
306 /*
307 * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
308 */
309
310 METHODDEF(void)
h2v2_merged_upsample(j_decompress_ptr cinfo,JSAMPIMAGE input_buf,JDIMENSION in_row_group_ctr,JSAMPARRAY output_buf)311 h2v2_merged_upsample (j_decompress_ptr cinfo,
312 JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
313 JSAMPARRAY output_buf)
314 {
315 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
316 register int y, cred, cgreen, cblue;
317 int cb, cr;
318 register JSAMPROW outptr0, outptr1;
319 JSAMPROW inptr00, inptr01, inptr1, inptr2;
320 JDIMENSION col;
321 /* copy these pointers into registers if possible */
322 register JSAMPLE * range_limit = cinfo->sample_range_limit;
323 int * Crrtab = upsample->Cr_r_tab;
324 int * Cbbtab = upsample->Cb_b_tab;
325 IJG_INT32 * Crgtab = upsample->Cr_g_tab;
326 IJG_INT32 * Cbgtab = upsample->Cb_g_tab;
327 SHIFT_TEMPS
328
329 inptr00 = input_buf[0][in_row_group_ctr*2];
330 inptr01 = input_buf[0][in_row_group_ctr*2 + 1];
331 inptr1 = input_buf[1][in_row_group_ctr];
332 inptr2 = input_buf[2][in_row_group_ctr];
333 outptr0 = output_buf[0];
334 outptr1 = output_buf[1];
335 /* Loop for each group of output pixels */
336 for (col = cinfo->output_width >> 1; col > 0; col--) {
337 /* Do the chroma part of the calculation */
338 cb = GETJSAMPLE(*inptr1++);
339 cr = GETJSAMPLE(*inptr2++);
340 cred = Crrtab[cr];
341 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
342 cblue = Cbbtab[cb];
343 /* Fetch 4 Y values and emit 4 pixels */
344 y = GETJSAMPLE(*inptr00++);
345 outptr0[RGB_RED] = range_limit[y + cred];
346 outptr0[RGB_GREEN] = range_limit[y + cgreen];
347 outptr0[RGB_BLUE] = range_limit[y + cblue];
348 outptr0 += RGB_PIXELSIZE;
349 y = GETJSAMPLE(*inptr00++);
350 outptr0[RGB_RED] = range_limit[y + cred];
351 outptr0[RGB_GREEN] = range_limit[y + cgreen];
352 outptr0[RGB_BLUE] = range_limit[y + cblue];
353 outptr0 += RGB_PIXELSIZE;
354 y = GETJSAMPLE(*inptr01++);
355 outptr1[RGB_RED] = range_limit[y + cred];
356 outptr1[RGB_GREEN] = range_limit[y + cgreen];
357 outptr1[RGB_BLUE] = range_limit[y + cblue];
358 outptr1 += RGB_PIXELSIZE;
359 y = GETJSAMPLE(*inptr01++);
360 outptr1[RGB_RED] = range_limit[y + cred];
361 outptr1[RGB_GREEN] = range_limit[y + cgreen];
362 outptr1[RGB_BLUE] = range_limit[y + cblue];
363 outptr1 += RGB_PIXELSIZE;
364 }
365 /* If image width is odd, do the last output column separately */
366 if (cinfo->output_width & 1) {
367 cb = GETJSAMPLE(*inptr1);
368 cr = GETJSAMPLE(*inptr2);
369 cred = Crrtab[cr];
370 cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
371 cblue = Cbbtab[cb];
372 y = GETJSAMPLE(*inptr00);
373 outptr0[RGB_RED] = range_limit[y + cred];
374 outptr0[RGB_GREEN] = range_limit[y + cgreen];
375 outptr0[RGB_BLUE] = range_limit[y + cblue];
376 y = GETJSAMPLE(*inptr01);
377 outptr1[RGB_RED] = range_limit[y + cred];
378 outptr1[RGB_GREEN] = range_limit[y + cgreen];
379 outptr1[RGB_BLUE] = range_limit[y + cblue];
380 }
381 }
382
383
384 /*
385 * Module initialization routine for merged upsampling/color conversion.
386 *
387 * NB: this is called under the conditions determined by use_merged_upsample()
388 * in jdmaster.c. That routine MUST correspond to the actual capabilities
389 * of this module; no safety checks are made here.
390 */
391
392 GLOBAL(void)
jinit_merged_upsampler(j_decompress_ptr cinfo)393 jinit_merged_upsampler (j_decompress_ptr cinfo)
394 {
395 my_upsample_ptr upsample;
396
397 upsample = (my_upsample_ptr)
398 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
399 SIZEOF(my_upsampler));
400 cinfo->upsample = (struct jpeg_upsampler *) upsample;
401 upsample->pub.start_pass = start_pass_merged_upsample;
402 upsample->pub.need_context_rows = FALSE;
403
404 upsample->out_row_width = cinfo->output_width * (JDIMENSION)cinfo->out_color_components;
405
406 if (cinfo->max_v_samp_factor == 2) {
407 upsample->pub.upsample = merged_2v_upsample;
408 upsample->upmethod = h2v2_merged_upsample;
409 /* Allocate a spare row buffer */
410 upsample->spare_row = (JSAMPROW)
411 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
412 (size_t) (upsample->out_row_width * SIZEOF(JSAMPLE)));
413 } else {
414 upsample->pub.upsample = merged_1v_upsample;
415 upsample->upmethod = h2v1_merged_upsample;
416 /* No spare row needed */
417 upsample->spare_row = NULL;
418 }
419
420 build_ycc_rgb_table(cinfo);
421 }
422
423 #endif /* UPSAMPLE_MERGING_SUPPORTED */
424