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1/*
2 * WebP (.webp) image decoder
3 * Copyright (c) 2013 Aneesh Dogra <aneesh@sugarlabs.org>
4 * Copyright (c) 2013 Justin Ruggles <justin.ruggles@gmail.com>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * WebP image decoder
26 *
27 * @author Aneesh Dogra <aneesh@sugarlabs.org>
28 * Container and Lossy decoding
29 *
30 * @author Justin Ruggles <justin.ruggles@gmail.com>
31 * Lossless decoder
32 * Compressed alpha for lossy
33 *
34 * @author James Almer <jamrial@gmail.com>
35 * Exif metadata
36 *
37 * Unimplemented:
38 * - Animation
39 * - ICC profile
40 * - XMP metadata
41 */
42
43#include "libavutil/imgutils.h"
44
45#define BITSTREAM_READER_LE
46#include "avcodec.h"
47#include "bytestream.h"
48#include "exif.h"
49#include "get_bits.h"
50#include "internal.h"
51#include "thread.h"
52#include "vp8.h"
53
54#define VP8X_FLAG_ANIMATION 0x02
55#define VP8X_FLAG_XMP_METADATA 0x04
56#define VP8X_FLAG_EXIF_METADATA 0x08
57#define VP8X_FLAG_ALPHA 0x10
58#define VP8X_FLAG_ICC 0x20
59
60#define MAX_PALETTE_SIZE 256
61#define MAX_CACHE_BITS 11
62#define NUM_CODE_LENGTH_CODES 19
63#define HUFFMAN_CODES_PER_META_CODE 5
64#define NUM_LITERAL_CODES 256
65#define NUM_LENGTH_CODES 24
66#define NUM_DISTANCE_CODES 40
67#define NUM_SHORT_DISTANCES 120
68#define MAX_HUFFMAN_CODE_LENGTH 15
69
70static const uint16_t alphabet_sizes[HUFFMAN_CODES_PER_META_CODE] = {
71 NUM_LITERAL_CODES + NUM_LENGTH_CODES,
72 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
73 NUM_DISTANCE_CODES
74};
75
76static const uint8_t code_length_code_order[NUM_CODE_LENGTH_CODES] = {
77 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
78};
79
80static const int8_t lz77_distance_offsets[NUM_SHORT_DISTANCES][2] = {
81 { 0, 1 }, { 1, 0 }, { 1, 1 }, { -1, 1 }, { 0, 2 }, { 2, 0 }, { 1, 2 }, { -1, 2 },
82 { 2, 1 }, { -2, 1 }, { 2, 2 }, { -2, 2 }, { 0, 3 }, { 3, 0 }, { 1, 3 }, { -1, 3 },
83 { 3, 1 }, { -3, 1 }, { 2, 3 }, { -2, 3 }, { 3, 2 }, { -3, 2 }, { 0, 4 }, { 4, 0 },
84 { 1, 4 }, { -1, 4 }, { 4, 1 }, { -4, 1 }, { 3, 3 }, { -3, 3 }, { 2, 4 }, { -2, 4 },
85 { 4, 2 }, { -4, 2 }, { 0, 5 }, { 3, 4 }, { -3, 4 }, { 4, 3 }, { -4, 3 }, { 5, 0 },
86 { 1, 5 }, { -1, 5 }, { 5, 1 }, { -5, 1 }, { 2, 5 }, { -2, 5 }, { 5, 2 }, { -5, 2 },
87 { 4, 4 }, { -4, 4 }, { 3, 5 }, { -3, 5 }, { 5, 3 }, { -5, 3 }, { 0, 6 }, { 6, 0 },
88 { 1, 6 }, { -1, 6 }, { 6, 1 }, { -6, 1 }, { 2, 6 }, { -2, 6 }, { 6, 2 }, { -6, 2 },
89 { 4, 5 }, { -4, 5 }, { 5, 4 }, { -5, 4 }, { 3, 6 }, { -3, 6 }, { 6, 3 }, { -6, 3 },
90 { 0, 7 }, { 7, 0 }, { 1, 7 }, { -1, 7 }, { 5, 5 }, { -5, 5 }, { 7, 1 }, { -7, 1 },
91 { 4, 6 }, { -4, 6 }, { 6, 4 }, { -6, 4 }, { 2, 7 }, { -2, 7 }, { 7, 2 }, { -7, 2 },
92 { 3, 7 }, { -3, 7 }, { 7, 3 }, { -7, 3 }, { 5, 6 }, { -5, 6 }, { 6, 5 }, { -6, 5 },
93 { 8, 0 }, { 4, 7 }, { -4, 7 }, { 7, 4 }, { -7, 4 }, { 8, 1 }, { 8, 2 }, { 6, 6 },
94 { -6, 6 }, { 8, 3 }, { 5, 7 }, { -5, 7 }, { 7, 5 }, { -7, 5 }, { 8, 4 }, { 6, 7 },
95 { -6, 7 }, { 7, 6 }, { -7, 6 }, { 8, 5 }, { 7, 7 }, { -7, 7 }, { 8, 6 }, { 8, 7 }
96};
97
98enum AlphaCompression {
99 ALPHA_COMPRESSION_NONE,
100 ALPHA_COMPRESSION_VP8L,
101};
102
103enum AlphaFilter {
104 ALPHA_FILTER_NONE,
105 ALPHA_FILTER_HORIZONTAL,
106 ALPHA_FILTER_VERTICAL,
107 ALPHA_FILTER_GRADIENT,
108};
109
110enum TransformType {
111 PREDICTOR_TRANSFORM = 0,
112 COLOR_TRANSFORM = 1,
113 SUBTRACT_GREEN = 2,
114 COLOR_INDEXING_TRANSFORM = 3,
115};
116
117enum PredictionMode {
118 PRED_MODE_BLACK,
119 PRED_MODE_L,
120 PRED_MODE_T,
121 PRED_MODE_TR,
122 PRED_MODE_TL,
123 PRED_MODE_AVG_T_AVG_L_TR,
124 PRED_MODE_AVG_L_TL,
125 PRED_MODE_AVG_L_T,
126 PRED_MODE_AVG_TL_T,
127 PRED_MODE_AVG_T_TR,
128 PRED_MODE_AVG_AVG_L_TL_AVG_T_TR,
129 PRED_MODE_SELECT,
130 PRED_MODE_ADD_SUBTRACT_FULL,
131 PRED_MODE_ADD_SUBTRACT_HALF,
132};
133
134enum HuffmanIndex {
135 HUFF_IDX_GREEN = 0,
136 HUFF_IDX_RED = 1,
137 HUFF_IDX_BLUE = 2,
138 HUFF_IDX_ALPHA = 3,
139 HUFF_IDX_DIST = 4
140};
141
142/* The structure of WebP lossless is an optional series of transformation data,
143 * followed by the primary image. The primary image also optionally contains
144 * an entropy group mapping if there are multiple entropy groups. There is a
145 * basic image type called an "entropy coded image" that is used for all of
146 * these. The type of each entropy coded image is referred to by the
147 * specification as its role. */
148enum ImageRole {
149 /* Primary Image: Stores the actual pixels of the image. */
150 IMAGE_ROLE_ARGB,
151
152 /* Entropy Image: Defines which Huffman group to use for different areas of
153 * the primary image. */
154 IMAGE_ROLE_ENTROPY,
155
156 /* Predictors: Defines which predictor type to use for different areas of
157 * the primary image. */
158 IMAGE_ROLE_PREDICTOR,
159
160 /* Color Transform Data: Defines the color transformation for different
161 * areas of the primary image. */
162 IMAGE_ROLE_COLOR_TRANSFORM,
163
164 /* Color Index: Stored as an image of height == 1. */
165 IMAGE_ROLE_COLOR_INDEXING,
166
167 IMAGE_ROLE_NB,
168};
169
170typedef struct HuffReader {
171 VLC vlc; /* Huffman decoder context */
172 int simple; /* whether to use simple mode */
173 int nb_symbols; /* number of coded symbols */
174 uint16_t simple_symbols[2]; /* symbols for simple mode */
175} HuffReader;
176
177typedef struct ImageContext {
178 enum ImageRole role; /* role of this image */
179 AVFrame *frame; /* AVFrame for data */
180 int color_cache_bits; /* color cache size, log2 */
181 uint32_t *color_cache; /* color cache data */
182 int nb_huffman_groups; /* number of huffman groups */
183 HuffReader *huffman_groups; /* reader for each huffman group */
184 int size_reduction; /* relative size compared to primary image, log2 */
185 int is_alpha_primary;
186} ImageContext;
187
188typedef struct WebPContext {
189 VP8Context v; /* VP8 Context used for lossy decoding */
190 GetBitContext gb; /* bitstream reader for main image chunk */
191 AVFrame *alpha_frame; /* AVFrame for alpha data decompressed from VP8L */
192 AVCodecContext *avctx; /* parent AVCodecContext */
193 int initialized; /* set once the VP8 context is initialized */
194 int has_alpha; /* has a separate alpha chunk */
195 enum AlphaCompression alpha_compression; /* compression type for alpha chunk */
196 enum AlphaFilter alpha_filter; /* filtering method for alpha chunk */
197 uint8_t *alpha_data; /* alpha chunk data */
198 int alpha_data_size; /* alpha chunk data size */
199 int has_exif; /* set after an EXIF chunk has been processed */
200 int width; /* image width */
201 int height; /* image height */
202 int lossless; /* indicates lossless or lossy */
203
204 int nb_transforms; /* number of transforms */
205 enum TransformType transforms[4]; /* transformations used in the image, in order */
206 int reduced_width; /* reduced width for index image, if applicable */
207 int nb_huffman_groups; /* number of huffman groups in the primary image */
208 ImageContext image[IMAGE_ROLE_NB]; /* image context for each role */
209} WebPContext;
210
211#define GET_PIXEL(frame, x, y) \
212 ((frame)->data[0] + (y) * frame->linesize[0] + 4 * (x))
213
214#define GET_PIXEL_COMP(frame, x, y, c) \
215 (*((frame)->data[0] + (y) * frame->linesize[0] + 4 * (x) + c))
216
217static void image_ctx_free(ImageContext *img)
218{
219 int i, j;
220
221 av_free(img->color_cache);
222 if (img->role != IMAGE_ROLE_ARGB && !img->is_alpha_primary)
223 av_frame_free(&img->frame);
224 if (img->huffman_groups) {
225 for (i = 0; i < img->nb_huffman_groups; i++) {
226 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; j++)
227 ff_free_vlc(&img->huffman_groups[i * HUFFMAN_CODES_PER_META_CODE + j].vlc);
228 }
229 av_free(img->huffman_groups);
230 }
231 memset(img, 0, sizeof(*img));
232}
233
234
235/* Differs from get_vlc2() in the following ways:
236 * - codes are bit-reversed
237 * - assumes 8-bit table to make reversal simpler
238 * - assumes max depth of 2 since the max code length for WebP is 15
239 */
240static av_always_inline int webp_get_vlc(GetBitContext *gb, VLC_TYPE (*table)[2])
241{
242 int n, nb_bits;
243 unsigned int index;
244 int code;
245
246 OPEN_READER(re, gb);
247 UPDATE_CACHE(re, gb);
248
249 index = SHOW_UBITS(re, gb, 8);
250 index = ff_reverse[index];
251 code = table[index][0];
252 n = table[index][1];
253
254 if (n < 0) {
255 LAST_SKIP_BITS(re, gb, 8);
256 UPDATE_CACHE(re, gb);
257
258 nb_bits = -n;
259
260 index = SHOW_UBITS(re, gb, nb_bits);
261 index = (ff_reverse[index] >> (8 - nb_bits)) + code;
262 code = table[index][0];
263 n = table[index][1];
264 }
265 SKIP_BITS(re, gb, n);
266
267 CLOSE_READER(re, gb);
268
269 return code;
270}
271
272static int huff_reader_get_symbol(HuffReader *r, GetBitContext *gb)
273{
274 if (r->simple) {
275 if (r->nb_symbols == 1)
276 return r->simple_symbols[0];
277 else
278 return r->simple_symbols[get_bits1(gb)];
279 } else
280 return webp_get_vlc(gb, r->vlc.table);
281}
282
283static int huff_reader_build_canonical(HuffReader *r, int *code_lengths,
284 int alphabet_size)
285{
286 int len = 0, sym, code = 0, ret;
287 int max_code_length = 0;
288 uint16_t *codes;
289
290 /* special-case 1 symbol since the vlc reader cannot handle it */
291 for (sym = 0; sym < alphabet_size; sym++) {
292 if (code_lengths[sym] > 0) {
293 len++;
294 code = sym;
295 if (len > 1)
296 break;
297 }
298 }
299 if (len == 1) {
300 r->nb_symbols = 1;
301 r->simple_symbols[0] = code;
302 r->simple = 1;
303 return 0;
304 }
305
306 for (sym = 0; sym < alphabet_size; sym++)
307 max_code_length = FFMAX(max_code_length, code_lengths[sym]);
308
309 if (max_code_length == 0 || max_code_length > MAX_HUFFMAN_CODE_LENGTH)
310 return AVERROR(EINVAL);
311
312 codes = av_malloc_array(alphabet_size, sizeof(*codes));
313 if (!codes)
314 return AVERROR(ENOMEM);
315
316 code = 0;
317 r->nb_symbols = 0;
318 for (len = 1; len <= max_code_length; len++) {
319 for (sym = 0; sym < alphabet_size; sym++) {
320 if (code_lengths[sym] != len)
321 continue;
322 codes[sym] = code++;
323 r->nb_symbols++;
324 }
325 code <<= 1;
326 }
327 if (!r->nb_symbols) {
328 av_free(codes);
329 return AVERROR_INVALIDDATA;
330 }
331
332 ret = init_vlc(&r->vlc, 8, alphabet_size,
333 code_lengths, sizeof(*code_lengths), sizeof(*code_lengths),
334 codes, sizeof(*codes), sizeof(*codes), 0);
335 if (ret < 0) {
336 av_free(codes);
337 return ret;
338 }
339 r->simple = 0;
340
341 av_free(codes);
342 return 0;
343}
344
345static void read_huffman_code_simple(WebPContext *s, HuffReader *hc)
346{
347 hc->nb_symbols = get_bits1(&s->gb) + 1;
348
349 if (get_bits1(&s->gb))
350 hc->simple_symbols[0] = get_bits(&s->gb, 8);
351 else
352 hc->simple_symbols[0] = get_bits1(&s->gb);
353
354 if (hc->nb_symbols == 2)
355 hc->simple_symbols[1] = get_bits(&s->gb, 8);
356
357 hc->simple = 1;
358}
359
360static int read_huffman_code_normal(WebPContext *s, HuffReader *hc,
361 int alphabet_size)
362{
363 HuffReader code_len_hc = { { 0 }, 0, 0, { 0 } };
364 int *code_lengths = NULL;
365 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
366 int i, symbol, max_symbol, prev_code_len, ret;
367 int num_codes = 4 + get_bits(&s->gb, 4);
368
369 if (num_codes > NUM_CODE_LENGTH_CODES)
370 return AVERROR_INVALIDDATA;
371
372 for (i = 0; i < num_codes; i++)
373 code_length_code_lengths[code_length_code_order[i]] = get_bits(&s->gb, 3);
374
375 ret = huff_reader_build_canonical(&code_len_hc, code_length_code_lengths,
376 NUM_CODE_LENGTH_CODES);
377 if (ret < 0)
378 goto finish;
379
380 code_lengths = av_mallocz_array(alphabet_size, sizeof(*code_lengths));
381 if (!code_lengths) {
382 ret = AVERROR(ENOMEM);
383 goto finish;
384 }
385
386 if (get_bits1(&s->gb)) {
387 int bits = 2 + 2 * get_bits(&s->gb, 3);
388 max_symbol = 2 + get_bits(&s->gb, bits);
389 if (max_symbol > alphabet_size) {
390 av_log(s->avctx, AV_LOG_ERROR, "max symbol %d > alphabet size %d\n",
391 max_symbol, alphabet_size);
392 ret = AVERROR_INVALIDDATA;
393 goto finish;
394 }
395 } else {
396 max_symbol = alphabet_size;
397 }
398
399 prev_code_len = 8;
400 symbol = 0;
401 while (symbol < alphabet_size) {
402 int code_len;
403
404 if (!max_symbol--)
405 break;
406 code_len = huff_reader_get_symbol(&code_len_hc, &s->gb);
407 if (code_len < 16) {
408 /* Code length code [0..15] indicates literal code lengths. */
409 code_lengths[symbol++] = code_len;
410 if (code_len)
411 prev_code_len = code_len;
412 } else {
413 int repeat = 0, length = 0;
414 switch (code_len) {
415 case 16:
416 /* Code 16 repeats the previous non-zero value [3..6] times,
417 * i.e., 3 + ReadBits(2) times. If code 16 is used before a
418 * non-zero value has been emitted, a value of 8 is repeated. */
419 repeat = 3 + get_bits(&s->gb, 2);
420 length = prev_code_len;
421 break;
422 case 17:
423 /* Code 17 emits a streak of zeros [3..10], i.e.,
424 * 3 + ReadBits(3) times. */
425 repeat = 3 + get_bits(&s->gb, 3);
426 break;
427 case 18:
428 /* Code 18 emits a streak of zeros of length [11..138], i.e.,
429 * 11 + ReadBits(7) times. */
430 repeat = 11 + get_bits(&s->gb, 7);
431 break;
432 }
433 if (symbol + repeat > alphabet_size) {
434 av_log(s->avctx, AV_LOG_ERROR,
435 "invalid symbol %d + repeat %d > alphabet size %d\n",
436 symbol, repeat, alphabet_size);
437 ret = AVERROR_INVALIDDATA;
438 goto finish;
439 }
440 while (repeat-- > 0)
441 code_lengths[symbol++] = length;
442 }
443 }
444
445 ret = huff_reader_build_canonical(hc, code_lengths, alphabet_size);
446
447finish:
448 ff_free_vlc(&code_len_hc.vlc);
449 av_free(code_lengths);
450 return ret;
451}
452
453static int decode_entropy_coded_image(WebPContext *s, enum ImageRole role,
454 int w, int h);
455
456#define PARSE_BLOCK_SIZE(w, h) do { \
457 block_bits = get_bits(&s->gb, 3) + 2; \
458 blocks_w = FFALIGN((w), 1 << block_bits) >> block_bits; \
459 blocks_h = FFALIGN((h), 1 << block_bits) >> block_bits; \
460} while (0)
461
462static int decode_entropy_image(WebPContext *s)
463{
464 ImageContext *img;
465 int ret, block_bits, width, blocks_w, blocks_h, x, y, max;
466
467 width = s->width;
468 if (s->reduced_width > 0)
469 width = s->reduced_width;
470
471 PARSE_BLOCK_SIZE(width, s->height);
472
473 ret = decode_entropy_coded_image(s, IMAGE_ROLE_ENTROPY, blocks_w, blocks_h);
474 if (ret < 0)
475 return ret;
476
477 img = &s->image[IMAGE_ROLE_ENTROPY];
478 img->size_reduction = block_bits;
479
480 /* the number of huffman groups is determined by the maximum group number
481 * coded in the entropy image */
482 max = 0;
483 for (y = 0; y < img->frame->height; y++) {
484 for (x = 0; x < img->frame->width; x++) {
485 int p0 = GET_PIXEL_COMP(img->frame, x, y, 1);
486 int p1 = GET_PIXEL_COMP(img->frame, x, y, 2);
487 int p = p0 << 8 | p1;
488 max = FFMAX(max, p);
489 }
490 }
491 s->nb_huffman_groups = max + 1;
492
493 return 0;
494}
495
496static int parse_transform_predictor(WebPContext *s)
497{
498 int block_bits, blocks_w, blocks_h, ret;
499
500 PARSE_BLOCK_SIZE(s->width, s->height);
501
502 ret = decode_entropy_coded_image(s, IMAGE_ROLE_PREDICTOR, blocks_w,
503 blocks_h);
504 if (ret < 0)
505 return ret;
506
507 s->image[IMAGE_ROLE_PREDICTOR].size_reduction = block_bits;
508
509 return 0;
510}
511
512static int parse_transform_color(WebPContext *s)
513{
514 int block_bits, blocks_w, blocks_h, ret;
515
516 PARSE_BLOCK_SIZE(s->width, s->height);
517
518 ret = decode_entropy_coded_image(s, IMAGE_ROLE_COLOR_TRANSFORM, blocks_w,
519 blocks_h);
520 if (ret < 0)
521 return ret;
522
523 s->image[IMAGE_ROLE_COLOR_TRANSFORM].size_reduction = block_bits;
524
525 return 0;
526}
527
528static int parse_transform_color_indexing(WebPContext *s)
529{
530 ImageContext *img;
531 int width_bits, index_size, ret, x;
532 uint8_t *ct;
533
534 index_size = get_bits(&s->gb, 8) + 1;
535
536 if (index_size <= 2)
537 width_bits = 3;
538 else if (index_size <= 4)
539 width_bits = 2;
540 else if (index_size <= 16)
541 width_bits = 1;
542 else
543 width_bits = 0;
544
545 ret = decode_entropy_coded_image(s, IMAGE_ROLE_COLOR_INDEXING,
546 index_size, 1);
547 if (ret < 0)
548 return ret;
549
550 img = &s->image[IMAGE_ROLE_COLOR_INDEXING];
551 img->size_reduction = width_bits;
552 if (width_bits > 0)
553 s->reduced_width = (s->width + ((1 << width_bits) - 1)) >> width_bits;
554
555 /* color index values are delta-coded */
556 ct = img->frame->data[0] + 4;
557 for (x = 4; x < img->frame->width * 4; x++, ct++)
558 ct[0] += ct[-4];
559
560 return 0;
561}
562
563static HuffReader *get_huffman_group(WebPContext *s, ImageContext *img,
564 int x, int y)
565{
566 ImageContext *gimg = &s->image[IMAGE_ROLE_ENTROPY];
567 int group = 0;
568
569 if (gimg->size_reduction > 0) {
570 int group_x = x >> gimg->size_reduction;
571 int group_y = y >> gimg->size_reduction;
572 int g0 = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 1);
573 int g1 = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 2);
574 group = g0 << 8 | g1;
575 }
576
577 return &img->huffman_groups[group * HUFFMAN_CODES_PER_META_CODE];
578}
579
580static av_always_inline void color_cache_put(ImageContext *img, uint32_t c)
581{
582 uint32_t cache_idx = (0x1E35A7BD * c) >> (32 - img->color_cache_bits);
583 img->color_cache[cache_idx] = c;
584}
585
586static int decode_entropy_coded_image(WebPContext *s, enum ImageRole role,
587 int w, int h)
588{
589 ImageContext *img;
590 HuffReader *hg;
591 int i, j, ret, x, y, width;
592
593 img = &s->image[role];
594 img->role = role;
595
596 if (!img->frame) {
597 img->frame = av_frame_alloc();
598 if (!img->frame)
599 return AVERROR(ENOMEM);
600 }
601
602 img->frame->format = AV_PIX_FMT_ARGB;
603 img->frame->width = w;
604 img->frame->height = h;
605
606 if (role == IMAGE_ROLE_ARGB && !img->is_alpha_primary) {
607 ThreadFrame pt = { .f = img->frame };
608 ret = ff_thread_get_buffer(s->avctx, &pt, 0);
609 } else
610 ret = av_frame_get_buffer(img->frame, 1);
611 if (ret < 0)
612 return ret;
613
614 if (get_bits1(&s->gb)) {
615 img->color_cache_bits = get_bits(&s->gb, 4);
616 if (img->color_cache_bits < 1 || img->color_cache_bits > 11) {
617 av_log(s->avctx, AV_LOG_ERROR, "invalid color cache bits: %d\n",
618 img->color_cache_bits);
619 return AVERROR_INVALIDDATA;
620 }
621 img->color_cache = av_mallocz_array(1 << img->color_cache_bits,
622 sizeof(*img->color_cache));
623 if (!img->color_cache)
624 return AVERROR(ENOMEM);
625 } else {
626 img->color_cache_bits = 0;
627 }
628
629 img->nb_huffman_groups = 1;
630 if (role == IMAGE_ROLE_ARGB && get_bits1(&s->gb)) {
631 ret = decode_entropy_image(s);
632 if (ret < 0)
633 return ret;
634 img->nb_huffman_groups = s->nb_huffman_groups;
635 }
636 img->huffman_groups = av_mallocz_array(img->nb_huffman_groups *
637 HUFFMAN_CODES_PER_META_CODE,
638 sizeof(*img->huffman_groups));
639 if (!img->huffman_groups)
640 return AVERROR(ENOMEM);
641
642 for (i = 0; i < img->nb_huffman_groups; i++) {
643 hg = &img->huffman_groups[i * HUFFMAN_CODES_PER_META_CODE];
644 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; j++) {
645 int alphabet_size = alphabet_sizes[j];
646 if (!j && img->color_cache_bits > 0)
647 alphabet_size += 1 << img->color_cache_bits;
648
649 if (get_bits1(&s->gb)) {
650 read_huffman_code_simple(s, &hg[j]);
651 } else {
652 ret = read_huffman_code_normal(s, &hg[j], alphabet_size);
653 if (ret < 0)
654 return ret;
655 }
656 }
657 }
658
659 width = img->frame->width;
660 if (role == IMAGE_ROLE_ARGB && s->reduced_width > 0)
661 width = s->reduced_width;
662
663 x = 0; y = 0;
664 while (y < img->frame->height) {
665 int v;
666
667 hg = get_huffman_group(s, img, x, y);
668 v = huff_reader_get_symbol(&hg[HUFF_IDX_GREEN], &s->gb);
669 if (v < NUM_LITERAL_CODES) {
670 /* literal pixel values */
671 uint8_t *p = GET_PIXEL(img->frame, x, y);
672 p[2] = v;
673 p[1] = huff_reader_get_symbol(&hg[HUFF_IDX_RED], &s->gb);
674 p[3] = huff_reader_get_symbol(&hg[HUFF_IDX_BLUE], &s->gb);
675 p[0] = huff_reader_get_symbol(&hg[HUFF_IDX_ALPHA], &s->gb);
676 if (img->color_cache_bits)
677 color_cache_put(img, AV_RB32(p));
678 x++;
679 if (x == width) {
680 x = 0;
681 y++;
682 }
683 } else if (v < NUM_LITERAL_CODES + NUM_LENGTH_CODES) {
684 /* LZ77 backwards mapping */
685 int prefix_code, length, distance, ref_x, ref_y;
686
687 /* parse length and distance */
688 prefix_code = v - NUM_LITERAL_CODES;
689 if (prefix_code < 4) {
690 length = prefix_code + 1;
691 } else {
692 int extra_bits = (prefix_code - 2) >> 1;
693 int offset = 2 + (prefix_code & 1) << extra_bits;
694 length = offset + get_bits(&s->gb, extra_bits) + 1;
695 }
696 prefix_code = huff_reader_get_symbol(&hg[HUFF_IDX_DIST], &s->gb);
697 if (prefix_code > 39) {
698 av_log(s->avctx, AV_LOG_ERROR,
699 "distance prefix code too large: %d\n", prefix_code);
700 return AVERROR_INVALIDDATA;
701 }
702 if (prefix_code < 4) {
703 distance = prefix_code + 1;
704 } else {
705 int extra_bits = prefix_code - 2 >> 1;
706 int offset = 2 + (prefix_code & 1) << extra_bits;
707 distance = offset + get_bits(&s->gb, extra_bits) + 1;
708 }
709
710 /* find reference location */
711 if (distance <= NUM_SHORT_DISTANCES) {
712 int xi = lz77_distance_offsets[distance - 1][0];
713 int yi = lz77_distance_offsets[distance - 1][1];
714 distance = FFMAX(1, xi + yi * width);
715 } else {
716 distance -= NUM_SHORT_DISTANCES;
717 }
718 ref_x = x;
719 ref_y = y;
720 if (distance <= x) {
721 ref_x -= distance;
722 distance = 0;
723 } else {
724 ref_x = 0;
725 distance -= x;
726 }
727 while (distance >= width) {
728 ref_y--;
729 distance -= width;
730 }
731 if (distance > 0) {
732 ref_x = width - distance;
733 ref_y--;
734 }
735 ref_x = FFMAX(0, ref_x);
736 ref_y = FFMAX(0, ref_y);
737
738 /* copy pixels
739 * source and dest regions can overlap and wrap lines, so just
740 * copy per-pixel */
741 for (i = 0; i < length; i++) {
742 uint8_t *p_ref = GET_PIXEL(img->frame, ref_x, ref_y);
743 uint8_t *p = GET_PIXEL(img->frame, x, y);
744
745 AV_COPY32(p, p_ref);
746 if (img->color_cache_bits)
747 color_cache_put(img, AV_RB32(p));
748 x++;
749 ref_x++;
750 if (x == width) {
751 x = 0;
752 y++;
753 }
754 if (ref_x == width) {
755 ref_x = 0;
756 ref_y++;
757 }
758 if (y == img->frame->height || ref_y == img->frame->height)
759 break;
760 }
761 } else {
762 /* read from color cache */
763 uint8_t *p = GET_PIXEL(img->frame, x, y);
764 int cache_idx = v - (NUM_LITERAL_CODES + NUM_LENGTH_CODES);
765
766 if (!img->color_cache_bits) {
767 av_log(s->avctx, AV_LOG_ERROR, "color cache not found\n");
768 return AVERROR_INVALIDDATA;
769 }
770 if (cache_idx >= 1 << img->color_cache_bits) {
771 av_log(s->avctx, AV_LOG_ERROR,
772 "color cache index out-of-bounds\n");
773 return AVERROR_INVALIDDATA;
774 }
775 AV_WB32(p, img->color_cache[cache_idx]);
776 x++;
777 if (x == width) {
778 x = 0;
779 y++;
780 }
781 }
782 }
783
784 return 0;
785}
786
787/* PRED_MODE_BLACK */
788static void inv_predict_0(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
789 const uint8_t *p_t, const uint8_t *p_tr)
790{
791 AV_WB32(p, 0xFF000000);
792}
793
794/* PRED_MODE_L */
795static void inv_predict_1(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
796 const uint8_t *p_t, const uint8_t *p_tr)
797{
798 AV_COPY32(p, p_l);
799}
800
801/* PRED_MODE_T */
802static void inv_predict_2(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
803 const uint8_t *p_t, const uint8_t *p_tr)
804{
805 AV_COPY32(p, p_t);
806}
807
808/* PRED_MODE_TR */
809static void inv_predict_3(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
810 const uint8_t *p_t, const uint8_t *p_tr)
811{
812 AV_COPY32(p, p_tr);
813}
814
815/* PRED_MODE_TL */
816static void inv_predict_4(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
817 const uint8_t *p_t, const uint8_t *p_tr)
818{
819 AV_COPY32(p, p_tl);
820}
821
822/* PRED_MODE_AVG_T_AVG_L_TR */
823static void inv_predict_5(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
824 const uint8_t *p_t, const uint8_t *p_tr)
825{
826 p[0] = p_t[0] + (p_l[0] + p_tr[0] >> 1) >> 1;
827 p[1] = p_t[1] + (p_l[1] + p_tr[1] >> 1) >> 1;
828 p[2] = p_t[2] + (p_l[2] + p_tr[2] >> 1) >> 1;
829 p[3] = p_t[3] + (p_l[3] + p_tr[3] >> 1) >> 1;
830}
831
832/* PRED_MODE_AVG_L_TL */
833static void inv_predict_6(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
834 const uint8_t *p_t, const uint8_t *p_tr)
835{
836 p[0] = p_l[0] + p_tl[0] >> 1;
837 p[1] = p_l[1] + p_tl[1] >> 1;
838 p[2] = p_l[2] + p_tl[2] >> 1;
839 p[3] = p_l[3] + p_tl[3] >> 1;
840}
841
842/* PRED_MODE_AVG_L_T */
843static void inv_predict_7(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
844 const uint8_t *p_t, const uint8_t *p_tr)
845{
846 p[0] = p_l[0] + p_t[0] >> 1;
847 p[1] = p_l[1] + p_t[1] >> 1;
848 p[2] = p_l[2] + p_t[2] >> 1;
849 p[3] = p_l[3] + p_t[3] >> 1;
850}
851
852/* PRED_MODE_AVG_TL_T */
853static void inv_predict_8(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
854 const uint8_t *p_t, const uint8_t *p_tr)
855{
856 p[0] = p_tl[0] + p_t[0] >> 1;
857 p[1] = p_tl[1] + p_t[1] >> 1;
858 p[2] = p_tl[2] + p_t[2] >> 1;
859 p[3] = p_tl[3] + p_t[3] >> 1;
860}
861
862/* PRED_MODE_AVG_T_TR */
863static void inv_predict_9(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
864 const uint8_t *p_t, const uint8_t *p_tr)
865{
866 p[0] = p_t[0] + p_tr[0] >> 1;
867 p[1] = p_t[1] + p_tr[1] >> 1;
868 p[2] = p_t[2] + p_tr[2] >> 1;
869 p[3] = p_t[3] + p_tr[3] >> 1;
870}
871
872/* PRED_MODE_AVG_AVG_L_TL_AVG_T_TR */
873static void inv_predict_10(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
874 const uint8_t *p_t, const uint8_t *p_tr)
875{
876 p[0] = (p_l[0] + p_tl[0] >> 1) + (p_t[0] + p_tr[0] >> 1) >> 1;
877 p[1] = (p_l[1] + p_tl[1] >> 1) + (p_t[1] + p_tr[1] >> 1) >> 1;
878 p[2] = (p_l[2] + p_tl[2] >> 1) + (p_t[2] + p_tr[2] >> 1) >> 1;
879 p[3] = (p_l[3] + p_tl[3] >> 1) + (p_t[3] + p_tr[3] >> 1) >> 1;
880}
881
882/* PRED_MODE_SELECT */
883static void inv_predict_11(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
884 const uint8_t *p_t, const uint8_t *p_tr)
885{
886 int diff = (FFABS(p_l[0] - p_tl[0]) - FFABS(p_t[0] - p_tl[0])) +
887 (FFABS(p_l[1] - p_tl[1]) - FFABS(p_t[1] - p_tl[1])) +
888 (FFABS(p_l[2] - p_tl[2]) - FFABS(p_t[2] - p_tl[2])) +
889 (FFABS(p_l[3] - p_tl[3]) - FFABS(p_t[3] - p_tl[3]));
890 if (diff <= 0)
891 AV_COPY32(p, p_t);
892 else
893 AV_COPY32(p, p_l);
894}
895
896/* PRED_MODE_ADD_SUBTRACT_FULL */
897static void inv_predict_12(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
898 const uint8_t *p_t, const uint8_t *p_tr)
899{
900 p[0] = av_clip_uint8(p_l[0] + p_t[0] - p_tl[0]);
901 p[1] = av_clip_uint8(p_l[1] + p_t[1] - p_tl[1]);
902 p[2] = av_clip_uint8(p_l[2] + p_t[2] - p_tl[2]);
903 p[3] = av_clip_uint8(p_l[3] + p_t[3] - p_tl[3]);
904}
905
906static av_always_inline uint8_t clamp_add_subtract_half(int a, int b, int c)
907{
908 int d = a + b >> 1;
909 return av_clip_uint8(d + (d - c) / 2);
910}
911
912/* PRED_MODE_ADD_SUBTRACT_HALF */
913static void inv_predict_13(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
914 const uint8_t *p_t, const uint8_t *p_tr)
915{
916 p[0] = clamp_add_subtract_half(p_l[0], p_t[0], p_tl[0]);
917 p[1] = clamp_add_subtract_half(p_l[1], p_t[1], p_tl[1]);
918 p[2] = clamp_add_subtract_half(p_l[2], p_t[2], p_tl[2]);
919 p[3] = clamp_add_subtract_half(p_l[3], p_t[3], p_tl[3]);
920}
921
922typedef void (*inv_predict_func)(uint8_t *p, const uint8_t *p_l,
923 const uint8_t *p_tl, const uint8_t *p_t,
924 const uint8_t *p_tr);
925
926static const inv_predict_func inverse_predict[14] = {
927 inv_predict_0, inv_predict_1, inv_predict_2, inv_predict_3,
928 inv_predict_4, inv_predict_5, inv_predict_6, inv_predict_7,
929 inv_predict_8, inv_predict_9, inv_predict_10, inv_predict_11,
930 inv_predict_12, inv_predict_13,
931};
932
933static void inverse_prediction(AVFrame *frame, enum PredictionMode m, int x, int y)
934{
935 uint8_t *dec, *p_l, *p_tl, *p_t, *p_tr;
936 uint8_t p[4];
937
938 dec = GET_PIXEL(frame, x, y);
939 p_l = GET_PIXEL(frame, x - 1, y);
940 p_tl = GET_PIXEL(frame, x - 1, y - 1);
941 p_t = GET_PIXEL(frame, x, y - 1);
942 if (x == frame->width - 1)
943 p_tr = GET_PIXEL(frame, 0, y);
944 else
945 p_tr = GET_PIXEL(frame, x + 1, y - 1);
946
947 inverse_predict[m](p, p_l, p_tl, p_t, p_tr);
948
949 dec[0] += p[0];
950 dec[1] += p[1];
951 dec[2] += p[2];
952 dec[3] += p[3];
953}
954
955static int apply_predictor_transform(WebPContext *s)
956{
957 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
958 ImageContext *pimg = &s->image[IMAGE_ROLE_PREDICTOR];
959 int x, y;
960
961 for (y = 0; y < img->frame->height; y++) {
962 for (x = 0; x < img->frame->width; x++) {
963 int tx = x >> pimg->size_reduction;
964 int ty = y >> pimg->size_reduction;
965 enum PredictionMode m = GET_PIXEL_COMP(pimg->frame, tx, ty, 2);
966
967 if (x == 0) {
968 if (y == 0)
969 m = PRED_MODE_BLACK;
970 else
971 m = PRED_MODE_T;
972 } else if (y == 0)
973 m = PRED_MODE_L;
974
975 if (m > 13) {
976 av_log(s->avctx, AV_LOG_ERROR,
977 "invalid predictor mode: %d\n", m);
978 return AVERROR_INVALIDDATA;
979 }
980 inverse_prediction(img->frame, m, x, y);
981 }
982 }
983 return 0;
984}
985
986static av_always_inline uint8_t color_transform_delta(uint8_t color_pred,
987 uint8_t color)
988{
989 return (int)ff_u8_to_s8(color_pred) * ff_u8_to_s8(color) >> 5;
990}
991
992static int apply_color_transform(WebPContext *s)
993{
994 ImageContext *img, *cimg;
995 int x, y, cx, cy;
996 uint8_t *p, *cp;
997
998 img = &s->image[IMAGE_ROLE_ARGB];
999 cimg = &s->image[IMAGE_ROLE_COLOR_TRANSFORM];
1000
1001 for (y = 0; y < img->frame->height; y++) {
1002 for (x = 0; x < img->frame->width; x++) {
1003 cx = x >> cimg->size_reduction;
1004 cy = y >> cimg->size_reduction;
1005 cp = GET_PIXEL(cimg->frame, cx, cy);
1006 p = GET_PIXEL(img->frame, x, y);
1007
1008 p[1] += color_transform_delta(cp[3], p[2]);
1009 p[3] += color_transform_delta(cp[2], p[2]) +
1010 color_transform_delta(cp[1], p[1]);
1011 }
1012 }
1013 return 0;
1014}
1015
1016static int apply_subtract_green_transform(WebPContext *s)
1017{
1018 int x, y;
1019 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
1020
1021 for (y = 0; y < img->frame->height; y++) {
1022 for (x = 0; x < img->frame->width; x++) {
1023 uint8_t *p = GET_PIXEL(img->frame, x, y);
1024 p[1] += p[2];
1025 p[3] += p[2];
1026 }
1027 }
1028 return 0;
1029}
1030
1031static int apply_color_indexing_transform(WebPContext *s)
1032{
1033 ImageContext *img;
1034 ImageContext *pal;
1035 int i, x, y;
1036 uint8_t *p;
1037
1038 img = &s->image[IMAGE_ROLE_ARGB];
1039 pal = &s->image[IMAGE_ROLE_COLOR_INDEXING];
1040
1041 if (pal->size_reduction > 0) {
1042 GetBitContext gb_g;
1043 uint8_t *line;
1044 int pixel_bits = 8 >> pal->size_reduction;
1045
1046 line = av_malloc(img->frame->linesize[0]);
1047 if (!line)
1048 return AVERROR(ENOMEM);
1049
1050 for (y = 0; y < img->frame->height; y++) {
1051 p = GET_PIXEL(img->frame, 0, y);
1052 memcpy(line, p, img->frame->linesize[0]);
1053 init_get_bits(&gb_g, line, img->frame->linesize[0] * 8);
1054 skip_bits(&gb_g, 16);
1055 i = 0;
1056 for (x = 0; x < img->frame->width; x++) {
1057 p = GET_PIXEL(img->frame, x, y);
1058 p[2] = get_bits(&gb_g, pixel_bits);
1059 i++;
1060 if (i == 1 << pal->size_reduction) {
1061 skip_bits(&gb_g, 24);
1062 i = 0;
1063 }
1064 }
1065 }
1066 av_free(line);
1067 }
1068
1069 // switch to local palette if it's worth initializing it
1070 if (img->frame->height * img->frame->width > 300) {
1071 uint8_t palette[256 * 4];
1072 const int size = pal->frame->width * 4;
1073 av_assert0(size <= 1024U);
1074 memcpy(palette, GET_PIXEL(pal->frame, 0, 0), size); // copy palette
1075 // set extra entries to transparent black
1076 memset(palette + size, 0, 256 * 4 - size);
1077 for (y = 0; y < img->frame->height; y++) {
1078 for (x = 0; x < img->frame->width; x++) {
1079 p = GET_PIXEL(img->frame, x, y);
1080 i = p[2];
1081 AV_COPY32(p, &palette[i * 4]);
1082 }
1083 }
1084 } else {
1085 for (y = 0; y < img->frame->height; y++) {
1086 for (x = 0; x < img->frame->width; x++) {
1087 p = GET_PIXEL(img->frame, x, y);
1088 i = p[2];
1089 if (i >= pal->frame->width) {
1090 AV_WB32(p, 0x00000000);
1091 } else {
1092 const uint8_t *pi = GET_PIXEL(pal->frame, i, 0);
1093 AV_COPY32(p, pi);
1094 }
1095 }
1096 }
1097 }
1098
1099 return 0;
1100}
1101
1102static int vp8_lossless_decode_frame(AVCodecContext *avctx, AVFrame *p,
1103 int *got_frame, uint8_t *data_start,
1104 unsigned int data_size, int is_alpha_chunk)
1105{
1106 WebPContext *s = avctx->priv_data;
1107 int w, h, ret, i, used;
1108
1109 if (!is_alpha_chunk) {
1110 s->lossless = 1;
1111 avctx->pix_fmt = AV_PIX_FMT_ARGB;
1112 }
1113
1114 ret = init_get_bits8(&s->gb, data_start, data_size);
1115 if (ret < 0)
1116 return ret;
1117
1118 if (!is_alpha_chunk) {
1119 if (get_bits(&s->gb, 8) != 0x2F) {
1120 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless signature\n");
1121 return AVERROR_INVALIDDATA;
1122 }
1123
1124 w = get_bits(&s->gb, 14) + 1;
1125 h = get_bits(&s->gb, 14) + 1;
1126 if (s->width && s->width != w) {
1127 av_log(avctx, AV_LOG_WARNING, "Width mismatch. %d != %d\n",
1128 s->width, w);
1129 }
1130 s->width = w;
1131 if (s->height && s->height != h) {
1132 av_log(avctx, AV_LOG_WARNING, "Height mismatch. %d != %d\n",
1133 s->width, w);
1134 }
1135 s->height = h;
1136
1137 ret = ff_set_dimensions(avctx, s->width, s->height);
1138 if (ret < 0)
1139 return ret;
1140
1141 s->has_alpha = get_bits1(&s->gb);
1142
1143 if (get_bits(&s->gb, 3) != 0x0) {
1144 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless version\n");
1145 return AVERROR_INVALIDDATA;
1146 }
1147 } else {
1148 if (!s->width || !s->height)
1149 return AVERROR_BUG;
1150 w = s->width;
1151 h = s->height;
1152 }
1153
1154 /* parse transformations */
1155 s->nb_transforms = 0;
1156 s->reduced_width = 0;
1157 used = 0;
1158 while (get_bits1(&s->gb)) {
1159 enum TransformType transform = get_bits(&s->gb, 2);
1160 if (used & (1 << transform)) {
1161 av_log(avctx, AV_LOG_ERROR, "Transform %d used more than once\n",
1162 transform);
1163 ret = AVERROR_INVALIDDATA;
1164 goto free_and_return;
1165 }
1166 used |= (1 << transform);
1167 s->transforms[s->nb_transforms++] = transform;
1168 switch (transform) {
1169 case PREDICTOR_TRANSFORM:
1170 ret = parse_transform_predictor(s);
1171 break;
1172 case COLOR_TRANSFORM:
1173 ret = parse_transform_color(s);
1174 break;
1175 case COLOR_INDEXING_TRANSFORM:
1176 ret = parse_transform_color_indexing(s);
1177 break;
1178 }
1179 if (ret < 0)
1180 goto free_and_return;
1181 }
1182
1183 /* decode primary image */
1184 s->image[IMAGE_ROLE_ARGB].frame = p;
1185 if (is_alpha_chunk)
1186 s->image[IMAGE_ROLE_ARGB].is_alpha_primary = 1;
1187 ret = decode_entropy_coded_image(s, IMAGE_ROLE_ARGB, w, h);
1188 if (ret < 0)
1189 goto free_and_return;
1190
1191 /* apply transformations */
1192 for (i = s->nb_transforms - 1; i >= 0; i--) {
1193 switch (s->transforms[i]) {
1194 case PREDICTOR_TRANSFORM:
1195 ret = apply_predictor_transform(s);
1196 break;
1197 case COLOR_TRANSFORM:
1198 ret = apply_color_transform(s);
1199 break;
1200 case SUBTRACT_GREEN:
1201 ret = apply_subtract_green_transform(s);
1202 break;
1203 case COLOR_INDEXING_TRANSFORM:
1204 ret = apply_color_indexing_transform(s);
1205 break;
1206 }
1207 if (ret < 0)
1208 goto free_and_return;
1209 }
1210
1211 *got_frame = 1;
1212 p->pict_type = AV_PICTURE_TYPE_I;
1213 p->key_frame = 1;
1214 ret = data_size;
1215
1216free_and_return:
1217 for (i = 0; i < IMAGE_ROLE_NB; i++)
1218 image_ctx_free(&s->image[i]);
1219
1220 return ret;
1221}
1222
1223static void alpha_inverse_prediction(AVFrame *frame, enum AlphaFilter m)
1224{
1225 int x, y, ls;
1226 uint8_t *dec;
1227
1228 ls = frame->linesize[3];
1229
1230 /* filter first row using horizontal filter */
1231 dec = frame->data[3] + 1;
1232 for (x = 1; x < frame->width; x++, dec++)
1233 *dec += *(dec - 1);
1234
1235 /* filter first column using vertical filter */
1236 dec = frame->data[3] + ls;
1237 for (y = 1; y < frame->height; y++, dec += ls)
1238 *dec += *(dec - ls);
1239
1240 /* filter the rest using the specified filter */
1241 switch (m) {
1242 case ALPHA_FILTER_HORIZONTAL:
1243 for (y = 1; y < frame->height; y++) {
1244 dec = frame->data[3] + y * ls + 1;
1245 for (x = 1; x < frame->width; x++, dec++)
1246 *dec += *(dec - 1);
1247 }
1248 break;
1249 case ALPHA_FILTER_VERTICAL:
1250 for (y = 1; y < frame->height; y++) {
1251 dec = frame->data[3] + y * ls + 1;
1252 for (x = 1; x < frame->width; x++, dec++)
1253 *dec += *(dec - ls);
1254 }
1255 break;
1256 case ALPHA_FILTER_GRADIENT:
1257 for (y = 1; y < frame->height; y++) {
1258 dec = frame->data[3] + y * ls + 1;
1259 for (x = 1; x < frame->width; x++, dec++)
1260 dec[0] += av_clip_uint8(*(dec - 1) + *(dec - ls) - *(dec - ls - 1));
1261 }
1262 break;
1263 }
1264}
1265
1266static int vp8_lossy_decode_alpha(AVCodecContext *avctx, AVFrame *p,
1267 uint8_t *data_start,
1268 unsigned int data_size)
1269{
1270 WebPContext *s = avctx->priv_data;
1271 int x, y, ret;
1272
1273 if (s->alpha_compression == ALPHA_COMPRESSION_NONE) {
1274 GetByteContext gb;
1275
1276 bytestream2_init(&gb, data_start, data_size);
1277 for (y = 0; y < s->height; y++)
1278 bytestream2_get_buffer(&gb, p->data[3] + p->linesize[3] * y,
1279 s->width);
1280 } else if (s->alpha_compression == ALPHA_COMPRESSION_VP8L) {
1281 uint8_t *ap, *pp;
1282 int alpha_got_frame = 0;
1283
1284 s->alpha_frame = av_frame_alloc();
1285 if (!s->alpha_frame)
1286 return AVERROR(ENOMEM);
1287
1288 ret = vp8_lossless_decode_frame(avctx, s->alpha_frame, &alpha_got_frame,
1289 data_start, data_size, 1);
1290 if (ret < 0) {
1291 av_frame_free(&s->alpha_frame);
1292 return ret;
1293 }
1294 if (!alpha_got_frame) {
1295 av_frame_free(&s->alpha_frame);
1296 return AVERROR_INVALIDDATA;
1297 }
1298
1299 /* copy green component of alpha image to alpha plane of primary image */
1300 for (y = 0; y < s->height; y++) {
1301 ap = GET_PIXEL(s->alpha_frame, 0, y) + 2;
1302 pp = p->data[3] + p->linesize[3] * y;
1303 for (x = 0; x < s->width; x++) {
1304 *pp = *ap;
1305 pp++;
1306 ap += 4;
1307 }
1308 }
1309 av_frame_free(&s->alpha_frame);
1310 }
1311
1312 /* apply alpha filtering */
1313 if (s->alpha_filter)
1314 alpha_inverse_prediction(p, s->alpha_filter);
1315
1316 return 0;
1317}
1318
1319static int vp8_lossy_decode_frame(AVCodecContext *avctx, AVFrame *p,
1320 int *got_frame, uint8_t *data_start,
1321 unsigned int data_size)
1322{
1323 WebPContext *s = avctx->priv_data;
1324 AVPacket pkt;
1325 int ret;
1326
1327 if (!s->initialized) {
1328 ff_vp8_decode_init(avctx);
1329 s->initialized = 1;
1330 if (s->has_alpha)
1331 avctx->pix_fmt = AV_PIX_FMT_YUVA420P;
1332 }
1333 s->lossless = 0;
1334
1335 if (data_size > INT_MAX) {
1336 av_log(avctx, AV_LOG_ERROR, "unsupported chunk size\n");
1337 return AVERROR_PATCHWELCOME;
1338 }
1339
1340 av_init_packet(&pkt);
1341 pkt.data = data_start;
1342 pkt.size = data_size;
1343
1344 ret = ff_vp8_decode_frame(avctx, p, got_frame, &pkt);
1345 if (s->has_alpha) {
1346 ret = vp8_lossy_decode_alpha(avctx, p, s->alpha_data,
1347 s->alpha_data_size);
1348 if (ret < 0)
1349 return ret;
1350 }
1351 return ret;
1352}
1353
1354static int webp_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
1355 AVPacket *avpkt)
1356{
1357 AVFrame * const p = data;
1358 WebPContext *s = avctx->priv_data;
1359 GetByteContext gb;
1360 int ret;
1361 uint32_t chunk_type, chunk_size;
1362 int vp8x_flags = 0;
1363
1364 s->avctx = avctx;
1365 s->width = 0;
1366 s->height = 0;
1367 *got_frame = 0;
1368 s->has_alpha = 0;
1369 s->has_exif = 0;
1370 bytestream2_init(&gb, avpkt->data, avpkt->size);
1371
1372 if (bytestream2_get_bytes_left(&gb) < 12)
1373 return AVERROR_INVALIDDATA;
1374
1375 if (bytestream2_get_le32(&gb) != MKTAG('R', 'I', 'F', 'F')) {
1376 av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
1377 return AVERROR_INVALIDDATA;
1378 }
1379
1380 chunk_size = bytestream2_get_le32(&gb);
1381 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1382 return AVERROR_INVALIDDATA;
1383
1384 if (bytestream2_get_le32(&gb) != MKTAG('W', 'E', 'B', 'P')) {
1385 av_log(avctx, AV_LOG_ERROR, "missing WEBP tag\n");
1386 return AVERROR_INVALIDDATA;
1387 }
1388
1389 while (bytestream2_get_bytes_left(&gb) > 8) {
1390 char chunk_str[5] = { 0 };
1391
1392 chunk_type = bytestream2_get_le32(&gb);
1393 chunk_size = bytestream2_get_le32(&gb);
1394 if (chunk_size == UINT32_MAX)
1395 return AVERROR_INVALIDDATA;
1396 chunk_size += chunk_size & 1;
1397
1398 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1399 return AVERROR_INVALIDDATA;
1400
1401 switch (chunk_type) {
1402 case MKTAG('V', 'P', '8', ' '):
1403 if (!*got_frame) {
1404 ret = vp8_lossy_decode_frame(avctx, p, got_frame,
1405 avpkt->data + bytestream2_tell(&gb),
1406 chunk_size);
1407 if (ret < 0)
1408 return ret;
1409 }
1410 bytestream2_skip(&gb, chunk_size);
1411 break;
1412 case MKTAG('V', 'P', '8', 'L'):
1413 if (!*got_frame) {
1414 ret = vp8_lossless_decode_frame(avctx, p, got_frame,
1415 avpkt->data + bytestream2_tell(&gb),
1416 chunk_size, 0);
1417 if (ret < 0)
1418 return ret;
1419 avctx->properties |= FF_CODEC_PROPERTY_LOSSLESS;
1420 }
1421 bytestream2_skip(&gb, chunk_size);
1422 break;
1423 case MKTAG('V', 'P', '8', 'X'):
1424 vp8x_flags = bytestream2_get_byte(&gb);
1425 bytestream2_skip(&gb, 3);
1426 s->width = bytestream2_get_le24(&gb) + 1;
1427 s->height = bytestream2_get_le24(&gb) + 1;
1428 ret = av_image_check_size(s->width, s->height, 0, avctx);
1429 if (ret < 0)
1430 return ret;
1431 break;
1432 case MKTAG('A', 'L', 'P', 'H'): {
1433 int alpha_header, filter_m, compression;
1434
1435 if (!(vp8x_flags & VP8X_FLAG_ALPHA)) {
1436 av_log(avctx, AV_LOG_WARNING,
1437 "ALPHA chunk present, but alpha bit not set in the "
1438 "VP8X header\n");
1439 }
1440 if (chunk_size == 0) {
1441 av_log(avctx, AV_LOG_ERROR, "invalid ALPHA chunk size\n");
1442 return AVERROR_INVALIDDATA;
1443 }
1444 alpha_header = bytestream2_get_byte(&gb);
1445 s->alpha_data = avpkt->data + bytestream2_tell(&gb);
1446 s->alpha_data_size = chunk_size - 1;
1447 bytestream2_skip(&gb, s->alpha_data_size);
1448
1449 filter_m = (alpha_header >> 2) & 0x03;
1450 compression = alpha_header & 0x03;
1451
1452 if (compression > ALPHA_COMPRESSION_VP8L) {
1453 av_log(avctx, AV_LOG_VERBOSE,
1454 "skipping unsupported ALPHA chunk\n");
1455 } else {
1456 s->has_alpha = 1;
1457 s->alpha_compression = compression;
1458 s->alpha_filter = filter_m;
1459 }
1460
1461 break;
1462 }
1463 case MKTAG('E', 'X', 'I', 'F'): {
1464 int le, ifd_offset, exif_offset = bytestream2_tell(&gb);
1465 AVDictionary *exif_metadata = NULL;
1466 GetByteContext exif_gb;
1467
1468 if (s->has_exif) {
1469 av_log(avctx, AV_LOG_VERBOSE, "Ignoring extra EXIF chunk\n");
1470 goto exif_end;
1471 }
1472 if (!(vp8x_flags & VP8X_FLAG_EXIF_METADATA))
1473 av_log(avctx, AV_LOG_WARNING,
1474 "EXIF chunk present, but Exif bit not set in the "
1475 "VP8X header\n");
1476
1477 s->has_exif = 1;
1478 bytestream2_init(&exif_gb, avpkt->data + exif_offset,
1479 avpkt->size - exif_offset);
1480 if (ff_tdecode_header(&exif_gb, &le, &ifd_offset) < 0) {
1481 av_log(avctx, AV_LOG_ERROR, "invalid TIFF header "
1482 "in Exif data\n");
1483 goto exif_end;
1484 }
1485
1486 bytestream2_seek(&exif_gb, ifd_offset, SEEK_SET);
1487 if (avpriv_exif_decode_ifd(avctx, &exif_gb, le, 0, &exif_metadata) < 0) {
1488 av_log(avctx, AV_LOG_ERROR, "error decoding Exif data\n");
1489 goto exif_end;
1490 }
1491
1492 av_dict_copy(avpriv_frame_get_metadatap(data), exif_metadata, 0);
1493
1494exif_end:
1495 av_dict_free(&exif_metadata);
1496 bytestream2_skip(&gb, chunk_size);
1497 break;
1498 }
1499 case MKTAG('I', 'C', 'C', 'P'):
1500 case MKTAG('A', 'N', 'I', 'M'):
1501 case MKTAG('A', 'N', 'M', 'F'):
1502 case MKTAG('X', 'M', 'P', ' '):
1503 AV_WL32(chunk_str, chunk_type);
1504 av_log(avctx, AV_LOG_WARNING, "skipping unsupported chunk: %s\n",
1505 chunk_str);
1506 bytestream2_skip(&gb, chunk_size);
1507 break;
1508 default:
1509 AV_WL32(chunk_str, chunk_type);
1510 av_log(avctx, AV_LOG_VERBOSE, "skipping unknown chunk: %s\n",
1511 chunk_str);
1512 bytestream2_skip(&gb, chunk_size);
1513 break;
1514 }
1515 }
1516
1517 if (!*got_frame) {
1518 av_log(avctx, AV_LOG_ERROR, "image data not found\n");
1519 return AVERROR_INVALIDDATA;
1520 }
1521
1522 return avpkt->size;
1523}
1524
1525static av_cold int webp_decode_close(AVCodecContext *avctx)
1526{
1527 WebPContext *s = avctx->priv_data;
1528
1529 if (s->initialized)
1530 return ff_vp8_decode_free(avctx);
1531
1532 return 0;
1533}
1534
1535AVCodec ff_webp_decoder = {
1536 .name = "webp",
1537 .long_name = NULL_IF_CONFIG_SMALL("WebP image"),
1538 .type = AVMEDIA_TYPE_VIDEO,
1539 .id = AV_CODEC_ID_WEBP,
1540 .priv_data_size = sizeof(WebPContext),
1541 .decode = webp_decode_frame,
1542 .close = webp_decode_close,
1543 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
1544};
1545
generated by cgit at 2024-05-17 03:08:53 (GMT)