1// Copyright 2011 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// functions for sample output.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include <assert.h>
15#include <stdlib.h>
16#include "src/dec/vp8i_dec.h"
17#include "src/dec/webpi_dec.h"
18#include "src/dsp/dsp.h"
19#include "src/dsp/yuv.h"
20#include "src/utils/utils.h"
21
22//------------------------------------------------------------------------------
23// Main YUV<->RGB conversion functions
24
25static int EmitYUV(const VP8Io* const io, WebPDecParams* const p) {
26 WebPDecBuffer* output = p->output;
27 const WebPYUVABuffer* const buf = &output->u.YUVA;
28 uint8_t* const y_dst = buf->y + io->mb_y * buf->y_stride;
29 uint8_t* const u_dst = buf->u + (io->mb_y >> 1) * buf->u_stride;
30 uint8_t* const v_dst = buf->v + (io->mb_y >> 1) * buf->v_stride;
31 const int mb_w = io->mb_w;
32 const int mb_h = io->mb_h;
33 const int uv_w = (mb_w + 1) / 2;
34 const int uv_h = (mb_h + 1) / 2;
35 int j;
36 for (j = 0; j < mb_h; ++j) {
37 memcpy(y_dst + j * buf->y_stride, io->y + j * io->y_stride, mb_w);
38 }
39 for (j = 0; j < uv_h; ++j) {
40 memcpy(u_dst + j * buf->u_stride, io->u + j * io->uv_stride, uv_w);
41 memcpy(v_dst + j * buf->v_stride, io->v + j * io->uv_stride, uv_w);
42 }
43 return io->mb_h;
44}
45
46// Point-sampling U/V sampler.
47static int EmitSampledRGB(const VP8Io* const io, WebPDecParams* const p) {
48 WebPDecBuffer* const output = p->output;
49 WebPRGBABuffer* const buf = &output->u.RGBA;
50 uint8_t* const dst = buf->rgba + io->mb_y * buf->stride;
51 WebPSamplerProcessPlane(io->y, io->y_stride,
52 io->u, io->v, io->uv_stride,
53 dst, buf->stride, io->mb_w, io->mb_h,
54 WebPSamplers[output->colorspace]);
55 return io->mb_h;
56}
57
58//------------------------------------------------------------------------------
59// Fancy upsampling
60
61#ifdef FANCY_UPSAMPLING
62static int EmitFancyRGB(const VP8Io* const io, WebPDecParams* const p) {
63 int num_lines_out = io->mb_h; // a priori guess
64 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
65 uint8_t* dst = buf->rgba + io->mb_y * buf->stride;
66 WebPUpsampleLinePairFunc upsample = WebPUpsamplers[p->output->colorspace];
67 const uint8_t* cur_y = io->y;
68 const uint8_t* cur_u = io->u;
69 const uint8_t* cur_v = io->v;
70 const uint8_t* top_u = p->tmp_u;
71 const uint8_t* top_v = p->tmp_v;
72 int y = io->mb_y;
73 const int y_end = io->mb_y + io->mb_h;
74 const int mb_w = io->mb_w;
75 const int uv_w = (mb_w + 1) / 2;
76
77 if (y == 0) {
78 // First line is special cased. We mirror the u/v samples at boundary.
79 upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v, dst, NULL, mb_w);
80 } else {
81 // We can finish the left-over line from previous call.
82 upsample(p->tmp_y, cur_y, top_u, top_v, cur_u, cur_v,
83 dst - buf->stride, dst, mb_w);
84 ++num_lines_out;
85 }
86 // Loop over each output pairs of row.
87 for (; y + 2 < y_end; y += 2) {
88 top_u = cur_u;
89 top_v = cur_v;
90 cur_u += io->uv_stride;
91 cur_v += io->uv_stride;
92 dst += 2 * buf->stride;
93 cur_y += 2 * io->y_stride;
94 upsample(cur_y - io->y_stride, cur_y,
95 top_u, top_v, cur_u, cur_v,
96 dst - buf->stride, dst, mb_w);
97 }
98 // move to last row
99 cur_y += io->y_stride;
100 if (io->crop_top + y_end < io->crop_bottom) {
101 // Save the unfinished samples for next call (as we're not done yet).
102 memcpy(p->tmp_y, cur_y, mb_w * sizeof(*p->tmp_y));
103 memcpy(p->tmp_u, cur_u, uv_w * sizeof(*p->tmp_u));
104 memcpy(p->tmp_v, cur_v, uv_w * sizeof(*p->tmp_v));
105 // The fancy upsampler leaves a row unfinished behind
106 // (except for the very last row)
107 num_lines_out--;
108 } else {
109 // Process the very last row of even-sized picture
110 if (!(y_end & 1)) {
111 upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v,
112 dst + buf->stride, NULL, mb_w);
113 }
114 }
115 return num_lines_out;
116}
117
118#endif /* FANCY_UPSAMPLING */
119
120//------------------------------------------------------------------------------
121
122static void FillAlphaPlane(uint8_t* dst, int w, int h, int stride) {
123 int j;
124 for (j = 0; j < h; ++j) {
125 memset(dst, 0xff, w * sizeof(*dst));
126 dst += stride;
127 }
128}
129
130static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
131 int expected_num_lines_out) {
132 const uint8_t* alpha = io->a;
133 const WebPYUVABuffer* const buf = &p->output->u.YUVA;
134 const int mb_w = io->mb_w;
135 const int mb_h = io->mb_h;
136 uint8_t* dst = buf->a + io->mb_y * buf->a_stride;
137 int j;
138 (void)expected_num_lines_out;
139 assert(expected_num_lines_out == mb_h);
140 if (alpha != NULL) {
141 for (j = 0; j < mb_h; ++j) {
142 memcpy(dst, alpha, mb_w * sizeof(*dst));
143 alpha += io->width;
144 dst += buf->a_stride;
145 }
146 } else if (buf->a != NULL) {
147 // the user requested alpha, but there is none, set it to opaque.
148 FillAlphaPlane(dst, mb_w, mb_h, buf->a_stride);
149 }
150 return 0;
151}
152
153static int GetAlphaSourceRow(const VP8Io* const io,
154 const uint8_t** alpha, int* const num_rows) {
155 int start_y = io->mb_y;
156 *num_rows = io->mb_h;
157
158 // Compensate for the 1-line delay of the fancy upscaler.
159 // This is similar to EmitFancyRGB().
160 if (io->fancy_upsampling) {
161 if (start_y == 0) {
162 // We don't process the last row yet. It'll be done during the next call.
163 --*num_rows;
164 } else {
165 --start_y;
166 // Fortunately, *alpha data is persistent, so we can go back
167 // one row and finish alpha blending, now that the fancy upscaler
168 // completed the YUV->RGB interpolation.
169 *alpha -= io->width;
170 }
171 if (io->crop_top + io->mb_y + io->mb_h == io->crop_bottom) {
172 // If it's the very last call, we process all the remaining rows!
173 *num_rows = io->crop_bottom - io->crop_top - start_y;
174 }
175 }
176 return start_y;
177}
178
179static int EmitAlphaRGB(const VP8Io* const io, WebPDecParams* const p,
180 int expected_num_lines_out) {
181 const uint8_t* alpha = io->a;
182 if (alpha != NULL) {
183 const int mb_w = io->mb_w;
184 const WEBP_CSP_MODE colorspace = p->output->colorspace;
185 const int alpha_first =
186 (colorspace == MODE_ARGB || colorspace == MODE_Argb);
187 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
188 int num_rows;
189 const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);
190 uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;
191 uint8_t* const dst = base_rgba + (alpha_first ? 0 : 3);
192 const int has_alpha = WebPDispatchAlpha(alpha, io->width, mb_w,
193 num_rows, dst, buf->stride);
194 (void)expected_num_lines_out;
195 assert(expected_num_lines_out == num_rows);
196 // has_alpha is true if there's non-trivial alpha to premultiply with.
197 if (has_alpha && WebPIsPremultipliedMode(colorspace)) {
198 WebPApplyAlphaMultiply(base_rgba, alpha_first,
199 mb_w, num_rows, buf->stride);
200 }
201 }
202 return 0;
203}
204
205static int EmitAlphaRGBA4444(const VP8Io* const io, WebPDecParams* const p,
206 int expected_num_lines_out) {
207 const uint8_t* alpha = io->a;
208 if (alpha != NULL) {
209 const int mb_w = io->mb_w;
210 const WEBP_CSP_MODE colorspace = p->output->colorspace;
211 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
212 int num_rows;
213 const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);
214 uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;
215#if (WEBP_SWAP_16BIT_CSP == 1)
216 uint8_t* alpha_dst = base_rgba;
217#else
218 uint8_t* alpha_dst = base_rgba + 1;
219#endif
220 uint32_t alpha_mask = 0x0f;
221 int i, j;
222 for (j = 0; j < num_rows; ++j) {
223 for (i = 0; i < mb_w; ++i) {
224 // Fill in the alpha value (converted to 4 bits).
225 const uint32_t alpha_value = alpha[i] >> 4;
226 alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;
227 alpha_mask &= alpha_value;
228 }
229 alpha += io->width;
230 alpha_dst += buf->stride;
231 }
232 (void)expected_num_lines_out;
233 assert(expected_num_lines_out == num_rows);
234 if (alpha_mask != 0x0f && WebPIsPremultipliedMode(colorspace)) {
235 WebPApplyAlphaMultiply4444(base_rgba, mb_w, num_rows, buf->stride);
236 }
237 }
238 return 0;
239}
240
241//------------------------------------------------------------------------------
242// YUV rescaling (no final RGB conversion needed)
243
244#if !defined(WEBP_REDUCE_SIZE)
245static int Rescale(const uint8_t* src, int src_stride,
246 int new_lines, WebPRescaler* const wrk) {
247 int num_lines_out = 0;
248 while (new_lines > 0) { // import new contributions of source rows.
249 const int lines_in = WebPRescalerImport(wrk, new_lines, src, src_stride);
250 src += lines_in * src_stride;
251 new_lines -= lines_in;
252 num_lines_out += WebPRescalerExport(wrk); // emit output row(s)
253 }
254 return num_lines_out;
255}
256
257static int EmitRescaledYUV(const VP8Io* const io, WebPDecParams* const p) {
258 const int mb_h = io->mb_h;
259 const int uv_mb_h = (mb_h + 1) >> 1;
260 WebPRescaler* const scaler = p->scaler_y;
261 int num_lines_out = 0;
262 if (WebPIsAlphaMode(p->output->colorspace) && io->a != NULL) {
263 // Before rescaling, we premultiply the luma directly into the io->y
264 // internal buffer. This is OK since these samples are not used for
265 // intra-prediction (the top samples are saved in cache_y_/u_/v_).
266 // But we need to cast the const away, though.
267 WebPMultRows((uint8_t*)io->y, io->y_stride,
268 io->a, io->width, io->mb_w, mb_h, 0);
269 }
270 num_lines_out = Rescale(io->y, io->y_stride, mb_h, scaler);
271 Rescale(io->u, io->uv_stride, uv_mb_h, p->scaler_u);
272 Rescale(io->v, io->uv_stride, uv_mb_h, p->scaler_v);
273 return num_lines_out;
274}
275
276static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
277 int expected_num_lines_out) {
278 const WebPYUVABuffer* const buf = &p->output->u.YUVA;
279 uint8_t* const dst_a = buf->a + p->last_y * buf->a_stride;
280 if (io->a != NULL) {
281 uint8_t* const dst_y = buf->y + p->last_y * buf->y_stride;
282 const int num_lines_out = Rescale(io->a, io->width, io->mb_h, p->scaler_a);
283 assert(expected_num_lines_out == num_lines_out);
284 if (num_lines_out > 0) { // unmultiply the Y
285 WebPMultRows(dst_y, buf->y_stride, dst_a, buf->a_stride,
286 p->scaler_a->dst_width, num_lines_out, 1);
287 }
288 } else if (buf->a != NULL) {
289 // the user requested alpha, but there is none, set it to opaque.
290 assert(p->last_y + expected_num_lines_out <= io->scaled_height);
291 FillAlphaPlane(dst_a, io->scaled_width, expected_num_lines_out,
292 buf->a_stride);
293 }
294 return 0;
295}
296
297static int InitYUVRescaler(const VP8Io* const io, WebPDecParams* const p) {
298 const int has_alpha = WebPIsAlphaMode(p->output->colorspace);
299 const WebPYUVABuffer* const buf = &p->output->u.YUVA;
300 const int out_width = io->scaled_width;
301 const int out_height = io->scaled_height;
302 const int uv_out_width = (out_width + 1) >> 1;
303 const int uv_out_height = (out_height + 1) >> 1;
304 const int uv_in_width = (io->mb_w + 1) >> 1;
305 const int uv_in_height = (io->mb_h + 1) >> 1;
306 const size_t work_size = 2 * out_width; // scratch memory for luma rescaler
307 const size_t uv_work_size = 2 * uv_out_width; // and for each u/v ones
308 size_t tmp_size, rescaler_size;
309 rescaler_t* work;
310 WebPRescaler* scalers;
311 const int num_rescalers = has_alpha ? 4 : 3;
312
313 tmp_size = (work_size + 2 * uv_work_size) * sizeof(*work);
314 if (has_alpha) {
315 tmp_size += work_size * sizeof(*work);
316 }
317 rescaler_size = num_rescalers * sizeof(*p->scaler_y) + WEBP_ALIGN_CST;
318
319 p->memory = WebPSafeMalloc(1ULL, tmp_size + rescaler_size);
320 if (p->memory == NULL) {
321 return 0; // memory error
322 }
323 work = (rescaler_t*)p->memory;
324
325 scalers = (WebPRescaler*)WEBP_ALIGN((const uint8_t*)work + tmp_size);
326 p->scaler_y = &scalers[0];
327 p->scaler_u = &scalers[1];
328 p->scaler_v = &scalers[2];
329 p->scaler_a = has_alpha ? &scalers[3] : NULL;
330
331 WebPRescalerInit(p->scaler_y, io->mb_w, io->mb_h,
332 buf->y, out_width, out_height, buf->y_stride, 1,
333 work);
334 WebPRescalerInit(p->scaler_u, uv_in_width, uv_in_height,
335 buf->u, uv_out_width, uv_out_height, buf->u_stride, 1,
336 work + work_size);
337 WebPRescalerInit(p->scaler_v, uv_in_width, uv_in_height,
338 buf->v, uv_out_width, uv_out_height, buf->v_stride, 1,
339 work + work_size + uv_work_size);
340 p->emit = EmitRescaledYUV;
341
342 if (has_alpha) {
343 WebPRescalerInit(p->scaler_a, io->mb_w, io->mb_h,
344 buf->a, out_width, out_height, buf->a_stride, 1,
345 work + work_size + 2 * uv_work_size);
346 p->emit_alpha = EmitRescaledAlphaYUV;
347 WebPInitAlphaProcessing();
348 }
349 return 1;
350}
351
352//------------------------------------------------------------------------------
353// RGBA rescaling
354
355static int ExportRGB(WebPDecParams* const p, int y_pos) {
356 const WebPYUV444Converter convert =
357 WebPYUV444Converters[p->output->colorspace];
358 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
359 uint8_t* dst = buf->rgba + y_pos * buf->stride;
360 int num_lines_out = 0;
361 // For RGB rescaling, because of the YUV420, current scan position
362 // U/V can be +1/-1 line from the Y one. Hence the double test.
363 while (WebPRescalerHasPendingOutput(p->scaler_y) &&
364 WebPRescalerHasPendingOutput(p->scaler_u)) {
365 assert(y_pos + num_lines_out < p->output->height);
366 assert(p->scaler_u->y_accum == p->scaler_v->y_accum);
367 WebPRescalerExportRow(p->scaler_y);
368 WebPRescalerExportRow(p->scaler_u);
369 WebPRescalerExportRow(p->scaler_v);
370 convert(p->scaler_y->dst, p->scaler_u->dst, p->scaler_v->dst,
371 dst, p->scaler_y->dst_width);
372 dst += buf->stride;
373 ++num_lines_out;
374 }
375 return num_lines_out;
376}
377
378static int EmitRescaledRGB(const VP8Io* const io, WebPDecParams* const p) {
379 const int mb_h = io->mb_h;
380 const int uv_mb_h = (mb_h + 1) >> 1;
381 int j = 0, uv_j = 0;
382 int num_lines_out = 0;
383 while (j < mb_h) {
384 const int y_lines_in =
385 WebPRescalerImport(p->scaler_y, mb_h - j,
386 io->y + j * io->y_stride, io->y_stride);
387 j += y_lines_in;
388 if (WebPRescaleNeededLines(p->scaler_u, uv_mb_h - uv_j)) {
389 const int u_lines_in =
390 WebPRescalerImport(p->scaler_u, uv_mb_h - uv_j,
391 io->u + uv_j * io->uv_stride, io->uv_stride);
392 const int v_lines_in =
393 WebPRescalerImport(p->scaler_v, uv_mb_h - uv_j,
394 io->v + uv_j * io->uv_stride, io->uv_stride);
395 (void)v_lines_in; // remove a gcc warning
396 assert(u_lines_in == v_lines_in);
397 uv_j += u_lines_in;
398 }
399 num_lines_out += ExportRGB(p, p->last_y + num_lines_out);
400 }
401 return num_lines_out;
402}
403
404static int ExportAlpha(WebPDecParams* const p, int y_pos, int max_lines_out) {
405 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
406 uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;
407 const WEBP_CSP_MODE colorspace = p->output->colorspace;
408 const int alpha_first =
409 (colorspace == MODE_ARGB || colorspace == MODE_Argb);
410 uint8_t* dst = base_rgba + (alpha_first ? 0 : 3);
411 int num_lines_out = 0;
412 const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);
413 uint32_t non_opaque = 0;
414 const int width = p->scaler_a->dst_width;
415
416 while (WebPRescalerHasPendingOutput(p->scaler_a) &&
417 num_lines_out < max_lines_out) {
418 assert(y_pos + num_lines_out < p->output->height);
419 WebPRescalerExportRow(p->scaler_a);
420 non_opaque |= WebPDispatchAlpha(p->scaler_a->dst, 0, width, 1, dst, 0);
421 dst += buf->stride;
422 ++num_lines_out;
423 }
424 if (is_premult_alpha && non_opaque) {
425 WebPApplyAlphaMultiply(base_rgba, alpha_first,
426 width, num_lines_out, buf->stride);
427 }
428 return num_lines_out;
429}
430
431static int ExportAlphaRGBA4444(WebPDecParams* const p, int y_pos,
432 int max_lines_out) {
433 const WebPRGBABuffer* const buf = &p->output->u.RGBA;
434 uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;
435#if (WEBP_SWAP_16BIT_CSP == 1)
436 uint8_t* alpha_dst = base_rgba;
437#else
438 uint8_t* alpha_dst = base_rgba + 1;
439#endif
440 int num_lines_out = 0;
441 const WEBP_CSP_MODE colorspace = p->output->colorspace;
442 const int width = p->scaler_a->dst_width;
443 const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);
444 uint32_t alpha_mask = 0x0f;
445
446 while (WebPRescalerHasPendingOutput(p->scaler_a) &&
447 num_lines_out < max_lines_out) {
448 int i;
449 assert(y_pos + num_lines_out < p->output->height);
450 WebPRescalerExportRow(p->scaler_a);
451 for (i = 0; i < width; ++i) {
452 // Fill in the alpha value (converted to 4 bits).
453 const uint32_t alpha_value = p->scaler_a->dst[i] >> 4;
454 alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;
455 alpha_mask &= alpha_value;
456 }
457 alpha_dst += buf->stride;
458 ++num_lines_out;
459 }
460 if (is_premult_alpha && alpha_mask != 0x0f) {
461 WebPApplyAlphaMultiply4444(base_rgba, width, num_lines_out, buf->stride);
462 }
463 return num_lines_out;
464}
465
466static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p,
467 int expected_num_out_lines) {
468 if (io->a != NULL) {
469 WebPRescaler* const scaler = p->scaler_a;
470 int lines_left = expected_num_out_lines;
471 const int y_end = p->last_y + lines_left;
472 while (lines_left > 0) {
473 const int row_offset = scaler->src_y - io->mb_y;
474 WebPRescalerImport(scaler, io->mb_h + io->mb_y - scaler->src_y,
475 io->a + row_offset * io->width, io->width);
476 lines_left -= p->emit_alpha_row(p, y_end - lines_left, lines_left);
477 }
478 }
479 return 0;
480}
481
482static int InitRGBRescaler(const VP8Io* const io, WebPDecParams* const p) {
483 const int has_alpha = WebPIsAlphaMode(p->output->colorspace);
484 const int out_width = io->scaled_width;
485 const int out_height = io->scaled_height;
486 const int uv_in_width = (io->mb_w + 1) >> 1;
487 const int uv_in_height = (io->mb_h + 1) >> 1;
488 const size_t work_size = 2 * out_width; // scratch memory for one rescaler
489 rescaler_t* work; // rescalers work area
490 uint8_t* tmp; // tmp storage for scaled YUV444 samples before RGB conversion
491 size_t tmp_size1, tmp_size2, total_size, rescaler_size;
492 WebPRescaler* scalers;
493 const int num_rescalers = has_alpha ? 4 : 3;
494
495 tmp_size1 = 3 * work_size;
496 tmp_size2 = 3 * out_width;
497 if (has_alpha) {
498 tmp_size1 += work_size;
499 tmp_size2 += out_width;
500 }
501 total_size = tmp_size1 * sizeof(*work) + tmp_size2 * sizeof(*tmp);
502 rescaler_size = num_rescalers * sizeof(*p->scaler_y) + WEBP_ALIGN_CST;
503
504 p->memory = WebPSafeMalloc(1ULL, total_size + rescaler_size);
505 if (p->memory == NULL) {
506 return 0; // memory error
507 }
508 work = (rescaler_t*)p->memory;
509 tmp = (uint8_t*)(work + tmp_size1);
510
511 scalers = (WebPRescaler*)WEBP_ALIGN((const uint8_t*)work + total_size);
512 p->scaler_y = &scalers[0];
513 p->scaler_u = &scalers[1];
514 p->scaler_v = &scalers[2];
515 p->scaler_a = has_alpha ? &scalers[3] : NULL;
516
517 WebPRescalerInit(p->scaler_y, io->mb_w, io->mb_h,
518 tmp + 0 * out_width, out_width, out_height, 0, 1,
519 work + 0 * work_size);
520 WebPRescalerInit(p->scaler_u, uv_in_width, uv_in_height,
521 tmp + 1 * out_width, out_width, out_height, 0, 1,
522 work + 1 * work_size);
523 WebPRescalerInit(p->scaler_v, uv_in_width, uv_in_height,
524 tmp + 2 * out_width, out_width, out_height, 0, 1,
525 work + 2 * work_size);
526 p->emit = EmitRescaledRGB;
527 WebPInitYUV444Converters();
528
529 if (has_alpha) {
530 WebPRescalerInit(p->scaler_a, io->mb_w, io->mb_h,
531 tmp + 3 * out_width, out_width, out_height, 0, 1,
532 work + 3 * work_size);
533 p->emit_alpha = EmitRescaledAlphaRGB;
534 if (p->output->colorspace == MODE_RGBA_4444 ||
535 p->output->colorspace == MODE_rgbA_4444) {
536 p->emit_alpha_row = ExportAlphaRGBA4444;
537 } else {
538 p->emit_alpha_row = ExportAlpha;
539 }
540 WebPInitAlphaProcessing();
541 }
542 return 1;
543}
544
545#endif // WEBP_REDUCE_SIZE
546
547//------------------------------------------------------------------------------
548// Default custom functions
549
550static int CustomSetup(VP8Io* io) {
551 WebPDecParams* const p = (WebPDecParams*)io->opaque;
552 const WEBP_CSP_MODE colorspace = p->output->colorspace;
553 const int is_rgb = WebPIsRGBMode(colorspace);
554 const int is_alpha = WebPIsAlphaMode(colorspace);
555
556 p->memory = NULL;
557 p->emit = NULL;
558 p->emit_alpha = NULL;
559 p->emit_alpha_row = NULL;
560 if (!WebPIoInitFromOptions(p->options, io, is_alpha ? MODE_YUV : MODE_YUVA)) {
561 return 0;
562 }
563 if (is_alpha && WebPIsPremultipliedMode(colorspace)) {
564 WebPInitUpsamplers();
565 }
566 if (io->use_scaling) {
567#if !defined(WEBP_REDUCE_SIZE)
568 const int ok = is_rgb ? InitRGBRescaler(io, p) : InitYUVRescaler(io, p);
569 if (!ok) {
570 return 0; // memory error
571 }
572#else
573 return 0; // rescaling support not compiled
574#endif
575 } else {
576 if (is_rgb) {
577 WebPInitSamplers();
578 p->emit = EmitSampledRGB; // default
579 if (io->fancy_upsampling) {
580#ifdef FANCY_UPSAMPLING
581 const int uv_width = (io->mb_w + 1) >> 1;
582 p->memory = WebPSafeMalloc(1ULL, (size_t)(io->mb_w + 2 * uv_width));
583 if (p->memory == NULL) {
584 return 0; // memory error.
585 }
586 p->tmp_y = (uint8_t*)p->memory;
587 p->tmp_u = p->tmp_y + io->mb_w;
588 p->tmp_v = p->tmp_u + uv_width;
589 p->emit = EmitFancyRGB;
590 WebPInitUpsamplers();
591#endif
592 }
593 } else {
594 p->emit = EmitYUV;
595 }
596 if (is_alpha) { // need transparency output
597 p->emit_alpha =
598 (colorspace == MODE_RGBA_4444 || colorspace == MODE_rgbA_4444) ?
599 EmitAlphaRGBA4444
600 : is_rgb ? EmitAlphaRGB
601 : EmitAlphaYUV;
602 if (is_rgb) {
603 WebPInitAlphaProcessing();
604 }
605 }
606 }
607
608 return 1;
609}
610
611//------------------------------------------------------------------------------
612
613static int CustomPut(const VP8Io* io) {
614 WebPDecParams* const p = (WebPDecParams*)io->opaque;
615 const int mb_w = io->mb_w;
616 const int mb_h = io->mb_h;
617 int num_lines_out;
618 assert(!(io->mb_y & 1));
619
620 if (mb_w <= 0 || mb_h <= 0) {
621 return 0;
622 }
623 num_lines_out = p->emit(io, p);
624 if (p->emit_alpha != NULL) {
625 p->emit_alpha(io, p, num_lines_out);
626 }
627 p->last_y += num_lines_out;
628 return 1;
629}
630
631//------------------------------------------------------------------------------
632
633static void CustomTeardown(const VP8Io* io) {
634 WebPDecParams* const p = (WebPDecParams*)io->opaque;
635 WebPSafeFree(p->memory);
636 p->memory = NULL;
637}
638
639//------------------------------------------------------------------------------
640// Main entry point
641
642void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io) {
643 io->put = CustomPut;
644 io->setup = CustomSetup;
645 io->teardown = CustomTeardown;
646 io->opaque = params;
647}
648
649//------------------------------------------------------------------------------
650