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