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Imported Debian version 2.5.0~trusty1.1
[deb_ffmpeg.git] / ffmpeg / libavcodec / webp.c
... / ...
CommitLineData
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#define BITSTREAM_READER_LE
44#include "libavutil/imgutils.h"
45#include "avcodec.h"
46#include "bytestream.h"
47#include "exif.h"
48#include "internal.h"
49#include "get_bits.h"
50#include "thread.h"
51#include "vp8.h"
52
53#define VP8X_FLAG_ANIMATION 0x02
54#define VP8X_FLAG_XMP_METADATA 0x04
55#define VP8X_FLAG_EXIF_METADATA 0x08
56#define VP8X_FLAG_ALPHA 0x10
57#define VP8X_FLAG_ICC 0x20
58
59#define MAX_PALETTE_SIZE 256
60#define MAX_CACHE_BITS 11
61#define NUM_CODE_LENGTH_CODES 19
62#define HUFFMAN_CODES_PER_META_CODE 5
63#define NUM_LITERAL_CODES 256
64#define NUM_LENGTH_CODES 24
65#define NUM_DISTANCE_CODES 40
66#define NUM_SHORT_DISTANCES 120
67#define MAX_HUFFMAN_CODE_LENGTH 15
68
69static const uint16_t alphabet_sizes[HUFFMAN_CODES_PER_META_CODE] = {
70 NUM_LITERAL_CODES + NUM_LENGTH_CODES,
71 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
72 NUM_DISTANCE_CODES
73};
74
75static const uint8_t code_length_code_order[NUM_CODE_LENGTH_CODES] = {
76 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
77};
78
79static const int8_t lz77_distance_offsets[NUM_SHORT_DISTANCES][2] = {
80 { 0, 1 }, { 1, 0 }, { 1, 1 }, { -1, 1 }, { 0, 2 }, { 2, 0 }, { 1, 2 }, { -1, 2 },
81 { 2, 1 }, { -2, 1 }, { 2, 2 }, { -2, 2 }, { 0, 3 }, { 3, 0 }, { 1, 3 }, { -1, 3 },
82 { 3, 1 }, { -3, 1 }, { 2, 3 }, { -2, 3 }, { 3, 2 }, { -3, 2 }, { 0, 4 }, { 4, 0 },
83 { 1, 4 }, { -1, 4 }, { 4, 1 }, { -4, 1 }, { 3, 3 }, { -3, 3 }, { 2, 4 }, { -2, 4 },
84 { 4, 2 }, { -4, 2 }, { 0, 5 }, { 3, 4 }, { -3, 4 }, { 4, 3 }, { -4, 3 }, { 5, 0 },
85 { 1, 5 }, { -1, 5 }, { 5, 1 }, { -5, 1 }, { 2, 5 }, { -2, 5 }, { 5, 2 }, { -5, 2 },
86 { 4, 4 }, { -4, 4 }, { 3, 5 }, { -3, 5 }, { 5, 3 }, { -5, 3 }, { 0, 6 }, { 6, 0 },
87 { 1, 6 }, { -1, 6 }, { 6, 1 }, { -6, 1 }, { 2, 6 }, { -2, 6 }, { 6, 2 }, { -6, 2 },
88 { 4, 5 }, { -4, 5 }, { 5, 4 }, { -5, 4 }, { 3, 6 }, { -3, 6 }, { 6, 3 }, { -6, 3 },
89 { 0, 7 }, { 7, 0 }, { 1, 7 }, { -1, 7 }, { 5, 5 }, { -5, 5 }, { 7, 1 }, { -7, 1 },
90 { 4, 6 }, { -4, 6 }, { 6, 4 }, { -6, 4 }, { 2, 7 }, { -2, 7 }, { 7, 2 }, { -7, 2 },
91 { 3, 7 }, { -3, 7 }, { 7, 3 }, { -7, 3 }, { 5, 6 }, { -5, 6 }, { 6, 5 }, { -6, 5 },
92 { 8, 0 }, { 4, 7 }, { -4, 7 }, { 7, 4 }, { -7, 4 }, { 8, 1 }, { 8, 2 }, { 6, 6 },
93 { -6, 6 }, { 8, 3 }, { 5, 7 }, { -5, 7 }, { 7, 5 }, { -7, 5 }, { 8, 4 }, { 6, 7 },
94 { -6, 7 }, { 7, 6 }, { -7, 6 }, { 8, 5 }, { 7, 7 }, { -7, 7 }, { 8, 6 }, { 8, 7 }
95};
96
97enum AlphaCompression {
98 ALPHA_COMPRESSION_NONE,
99 ALPHA_COMPRESSION_VP8L,
100};
101
102enum AlphaFilter {
103 ALPHA_FILTER_NONE,
104 ALPHA_FILTER_HORIZONTAL,
105 ALPHA_FILTER_VERTICAL,
106 ALPHA_FILTER_GRADIENT,
107};
108
109enum TransformType {
110 PREDICTOR_TRANSFORM = 0,
111 COLOR_TRANSFORM = 1,
112 SUBTRACT_GREEN = 2,
113 COLOR_INDEXING_TRANSFORM = 3,
114};
115
116enum PredictionMode {
117 PRED_MODE_BLACK,
118 PRED_MODE_L,
119 PRED_MODE_T,
120 PRED_MODE_TR,
121 PRED_MODE_TL,
122 PRED_MODE_AVG_T_AVG_L_TR,
123 PRED_MODE_AVG_L_TL,
124 PRED_MODE_AVG_L_T,
125 PRED_MODE_AVG_TL_T,
126 PRED_MODE_AVG_T_TR,
127 PRED_MODE_AVG_AVG_L_TL_AVG_T_TR,
128 PRED_MODE_SELECT,
129 PRED_MODE_ADD_SUBTRACT_FULL,
130 PRED_MODE_ADD_SUBTRACT_HALF,
131};
132
133enum HuffmanIndex {
134 HUFF_IDX_GREEN = 0,
135 HUFF_IDX_RED = 1,
136 HUFF_IDX_BLUE = 2,
137 HUFF_IDX_ALPHA = 3,
138 HUFF_IDX_DIST = 4
139};
140
141/* The structure of WebP lossless is an optional series of transformation data,
142 * followed by the primary image. The primary image also optionally contains
143 * an entropy group mapping if there are multiple entropy groups. There is a
144 * basic image type called an "entropy coded image" that is used for all of
145 * these. The type of each entropy coded image is referred to by the
146 * specification as its role. */
147enum ImageRole {
148 /* Primary Image: Stores the actual pixels of the image. */
149 IMAGE_ROLE_ARGB,
150
151 /* Entropy Image: Defines which Huffman group to use for different areas of
152 * the primary image. */
153 IMAGE_ROLE_ENTROPY,
154
155 /* Predictors: Defines which predictor type to use for different areas of
156 * the primary image. */
157 IMAGE_ROLE_PREDICTOR,
158
159 /* Color Transform Data: Defines the color transformation for different
160 * areas of the primary image. */
161 IMAGE_ROLE_COLOR_TRANSFORM,
162
163 /* Color Index: Stored as an image of height == 1. */
164 IMAGE_ROLE_COLOR_INDEXING,
165
166 IMAGE_ROLE_NB,
167};
168
169typedef struct HuffReader {
170 VLC vlc; /* Huffman decoder context */
171 int simple; /* whether to use simple mode */
172 int nb_symbols; /* number of coded symbols */
173 uint16_t simple_symbols[2]; /* symbols for simple mode */
174} HuffReader;
175
176typedef struct ImageContext {
177 enum ImageRole role; /* role of this image */
178 AVFrame *frame; /* AVFrame for data */
179 int color_cache_bits; /* color cache size, log2 */
180 uint32_t *color_cache; /* color cache data */
181 int nb_huffman_groups; /* number of huffman groups */
182 HuffReader *huffman_groups; /* reader for each huffman group */
183 int size_reduction; /* relative size compared to primary image, log2 */
184 int is_alpha_primary;
185} ImageContext;
186
187typedef struct WebPContext {
188 VP8Context v; /* VP8 Context used for lossy decoding */
189 GetBitContext gb; /* bitstream reader for main image chunk */
190 AVFrame *alpha_frame; /* AVFrame for alpha data decompressed from VP8L */
191 AVCodecContext *avctx; /* parent AVCodecContext */
192 int initialized; /* set once the VP8 context is initialized */
193 int has_alpha; /* has a separate alpha chunk */
194 enum AlphaCompression alpha_compression; /* compression type for alpha chunk */
195 enum AlphaFilter alpha_filter; /* filtering method for alpha chunk */
196 uint8_t *alpha_data; /* alpha chunk data */
197 int alpha_data_size; /* alpha chunk data size */
198 int has_exif; /* set after an EXIF chunk has been processed */
199 AVDictionary *exif_metadata; /* EXIF chunk data */
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 < 4) {
698 distance = prefix_code + 1;
699 } else {
700 int extra_bits = prefix_code - 2 >> 1;
701 int offset = 2 + (prefix_code & 1) << extra_bits;
702 distance = offset + get_bits(&s->gb, extra_bits) + 1;
703 }
704
705 /* find reference location */
706 if (distance <= NUM_SHORT_DISTANCES) {
707 int xi = lz77_distance_offsets[distance - 1][0];
708 int yi = lz77_distance_offsets[distance - 1][1];
709 distance = FFMAX(1, xi + yi * width);
710 } else {
711 distance -= NUM_SHORT_DISTANCES;
712 }
713 ref_x = x;
714 ref_y = y;
715 if (distance <= x) {
716 ref_x -= distance;
717 distance = 0;
718 } else {
719 ref_x = 0;
720 distance -= x;
721 }
722 while (distance >= width) {
723 ref_y--;
724 distance -= width;
725 }
726 if (distance > 0) {
727 ref_x = width - distance;
728 ref_y--;
729 }
730 ref_x = FFMAX(0, ref_x);
731 ref_y = FFMAX(0, ref_y);
732
733 /* copy pixels
734 * source and dest regions can overlap and wrap lines, so just
735 * copy per-pixel */
736 for (i = 0; i < length; i++) {
737 uint8_t *p_ref = GET_PIXEL(img->frame, ref_x, ref_y);
738 uint8_t *p = GET_PIXEL(img->frame, x, y);
739
740 AV_COPY32(p, p_ref);
741 if (img->color_cache_bits)
742 color_cache_put(img, AV_RB32(p));
743 x++;
744 ref_x++;
745 if (x == width) {
746 x = 0;
747 y++;
748 }
749 if (ref_x == width) {
750 ref_x = 0;
751 ref_y++;
752 }
753 if (y == img->frame->height || ref_y == img->frame->height)
754 break;
755 }
756 } else {
757 /* read from color cache */
758 uint8_t *p = GET_PIXEL(img->frame, x, y);
759 int cache_idx = v - (NUM_LITERAL_CODES + NUM_LENGTH_CODES);
760
761 if (!img->color_cache_bits) {
762 av_log(s->avctx, AV_LOG_ERROR, "color cache not found\n");
763 return AVERROR_INVALIDDATA;
764 }
765 if (cache_idx >= 1 << img->color_cache_bits) {
766 av_log(s->avctx, AV_LOG_ERROR,
767 "color cache index out-of-bounds\n");
768 return AVERROR_INVALIDDATA;
769 }
770 AV_WB32(p, img->color_cache[cache_idx]);
771 x++;
772 if (x == width) {
773 x = 0;
774 y++;
775 }
776 }
777 }
778
779 return 0;
780}
781
782/* PRED_MODE_BLACK */
783static void inv_predict_0(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
784 const uint8_t *p_t, const uint8_t *p_tr)
785{
786 AV_WB32(p, 0xFF000000);
787}
788
789/* PRED_MODE_L */
790static void inv_predict_1(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
791 const uint8_t *p_t, const uint8_t *p_tr)
792{
793 AV_COPY32(p, p_l);
794}
795
796/* PRED_MODE_T */
797static void inv_predict_2(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
798 const uint8_t *p_t, const uint8_t *p_tr)
799{
800 AV_COPY32(p, p_t);
801}
802
803/* PRED_MODE_TR */
804static void inv_predict_3(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
805 const uint8_t *p_t, const uint8_t *p_tr)
806{
807 AV_COPY32(p, p_tr);
808}
809
810/* PRED_MODE_TL */
811static void inv_predict_4(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
812 const uint8_t *p_t, const uint8_t *p_tr)
813{
814 AV_COPY32(p, p_tl);
815}
816
817/* PRED_MODE_AVG_T_AVG_L_TR */
818static void inv_predict_5(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
819 const uint8_t *p_t, const uint8_t *p_tr)
820{
821 p[0] = p_t[0] + (p_l[0] + p_tr[0] >> 1) >> 1;
822 p[1] = p_t[1] + (p_l[1] + p_tr[1] >> 1) >> 1;
823 p[2] = p_t[2] + (p_l[2] + p_tr[2] >> 1) >> 1;
824 p[3] = p_t[3] + (p_l[3] + p_tr[3] >> 1) >> 1;
825}
826
827/* PRED_MODE_AVG_L_TL */
828static void inv_predict_6(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
829 const uint8_t *p_t, const uint8_t *p_tr)
830{
831 p[0] = p_l[0] + p_tl[0] >> 1;
832 p[1] = p_l[1] + p_tl[1] >> 1;
833 p[2] = p_l[2] + p_tl[2] >> 1;
834 p[3] = p_l[3] + p_tl[3] >> 1;
835}
836
837/* PRED_MODE_AVG_L_T */
838static void inv_predict_7(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
839 const uint8_t *p_t, const uint8_t *p_tr)
840{
841 p[0] = p_l[0] + p_t[0] >> 1;
842 p[1] = p_l[1] + p_t[1] >> 1;
843 p[2] = p_l[2] + p_t[2] >> 1;
844 p[3] = p_l[3] + p_t[3] >> 1;
845}
846
847/* PRED_MODE_AVG_TL_T */
848static void inv_predict_8(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
849 const uint8_t *p_t, const uint8_t *p_tr)
850{
851 p[0] = p_tl[0] + p_t[0] >> 1;
852 p[1] = p_tl[1] + p_t[1] >> 1;
853 p[2] = p_tl[2] + p_t[2] >> 1;
854 p[3] = p_tl[3] + p_t[3] >> 1;
855}
856
857/* PRED_MODE_AVG_T_TR */
858static void inv_predict_9(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
859 const uint8_t *p_t, const uint8_t *p_tr)
860{
861 p[0] = p_t[0] + p_tr[0] >> 1;
862 p[1] = p_t[1] + p_tr[1] >> 1;
863 p[2] = p_t[2] + p_tr[2] >> 1;
864 p[3] = p_t[3] + p_tr[3] >> 1;
865}
866
867/* PRED_MODE_AVG_AVG_L_TL_AVG_T_TR */
868static void inv_predict_10(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
869 const uint8_t *p_t, const uint8_t *p_tr)
870{
871 p[0] = (p_l[0] + p_tl[0] >> 1) + (p_t[0] + p_tr[0] >> 1) >> 1;
872 p[1] = (p_l[1] + p_tl[1] >> 1) + (p_t[1] + p_tr[1] >> 1) >> 1;
873 p[2] = (p_l[2] + p_tl[2] >> 1) + (p_t[2] + p_tr[2] >> 1) >> 1;
874 p[3] = (p_l[3] + p_tl[3] >> 1) + (p_t[3] + p_tr[3] >> 1) >> 1;
875}
876
877/* PRED_MODE_SELECT */
878static void inv_predict_11(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
879 const uint8_t *p_t, const uint8_t *p_tr)
880{
881 int diff = (FFABS(p_l[0] - p_tl[0]) - FFABS(p_t[0] - p_tl[0])) +
882 (FFABS(p_l[1] - p_tl[1]) - FFABS(p_t[1] - p_tl[1])) +
883 (FFABS(p_l[2] - p_tl[2]) - FFABS(p_t[2] - p_tl[2])) +
884 (FFABS(p_l[3] - p_tl[3]) - FFABS(p_t[3] - p_tl[3]));
885 if (diff <= 0)
886 AV_COPY32(p, p_t);
887 else
888 AV_COPY32(p, p_l);
889}
890
891/* PRED_MODE_ADD_SUBTRACT_FULL */
892static void inv_predict_12(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
893 const uint8_t *p_t, const uint8_t *p_tr)
894{
895 p[0] = av_clip_uint8(p_l[0] + p_t[0] - p_tl[0]);
896 p[1] = av_clip_uint8(p_l[1] + p_t[1] - p_tl[1]);
897 p[2] = av_clip_uint8(p_l[2] + p_t[2] - p_tl[2]);
898 p[3] = av_clip_uint8(p_l[3] + p_t[3] - p_tl[3]);
899}
900
901static av_always_inline uint8_t clamp_add_subtract_half(int a, int b, int c)
902{
903 int d = a + b >> 1;
904 return av_clip_uint8(d + (d - c) / 2);
905}
906
907/* PRED_MODE_ADD_SUBTRACT_HALF */
908static void inv_predict_13(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
909 const uint8_t *p_t, const uint8_t *p_tr)
910{
911 p[0] = clamp_add_subtract_half(p_l[0], p_t[0], p_tl[0]);
912 p[1] = clamp_add_subtract_half(p_l[1], p_t[1], p_tl[1]);
913 p[2] = clamp_add_subtract_half(p_l[2], p_t[2], p_tl[2]);
914 p[3] = clamp_add_subtract_half(p_l[3], p_t[3], p_tl[3]);
915}
916
917typedef void (*inv_predict_func)(uint8_t *p, const uint8_t *p_l,
918 const uint8_t *p_tl, const uint8_t *p_t,
919 const uint8_t *p_tr);
920
921static const inv_predict_func inverse_predict[14] = {
922 inv_predict_0, inv_predict_1, inv_predict_2, inv_predict_3,
923 inv_predict_4, inv_predict_5, inv_predict_6, inv_predict_7,
924 inv_predict_8, inv_predict_9, inv_predict_10, inv_predict_11,
925 inv_predict_12, inv_predict_13,
926};
927
928static void inverse_prediction(AVFrame *frame, enum PredictionMode m, int x, int y)
929{
930 uint8_t *dec, *p_l, *p_tl, *p_t, *p_tr;
931 uint8_t p[4];
932
933 dec = GET_PIXEL(frame, x, y);
934 p_l = GET_PIXEL(frame, x - 1, y);
935 p_tl = GET_PIXEL(frame, x - 1, y - 1);
936 p_t = GET_PIXEL(frame, x, y - 1);
937 if (x == frame->width - 1)
938 p_tr = GET_PIXEL(frame, 0, y);
939 else
940 p_tr = GET_PIXEL(frame, x + 1, y - 1);
941
942 inverse_predict[m](p, p_l, p_tl, p_t, p_tr);
943
944 dec[0] += p[0];
945 dec[1] += p[1];
946 dec[2] += p[2];
947 dec[3] += p[3];
948}
949
950static int apply_predictor_transform(WebPContext *s)
951{
952 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
953 ImageContext *pimg = &s->image[IMAGE_ROLE_PREDICTOR];
954 int x, y;
955
956 for (y = 0; y < img->frame->height; y++) {
957 for (x = 0; x < img->frame->width; x++) {
958 int tx = x >> pimg->size_reduction;
959 int ty = y >> pimg->size_reduction;
960 enum PredictionMode m = GET_PIXEL_COMP(pimg->frame, tx, ty, 2);
961
962 if (x == 0) {
963 if (y == 0)
964 m = PRED_MODE_BLACK;
965 else
966 m = PRED_MODE_T;
967 } else if (y == 0)
968 m = PRED_MODE_L;
969
970 if (m > 13) {
971 av_log(s->avctx, AV_LOG_ERROR,
972 "invalid predictor mode: %d\n", m);
973 return AVERROR_INVALIDDATA;
974 }
975 inverse_prediction(img->frame, m, x, y);
976 }
977 }
978 return 0;
979}
980
981static av_always_inline uint8_t color_transform_delta(uint8_t color_pred,
982 uint8_t color)
983{
984 return (int)ff_u8_to_s8(color_pred) * ff_u8_to_s8(color) >> 5;
985}
986
987static int apply_color_transform(WebPContext *s)
988{
989 ImageContext *img, *cimg;
990 int x, y, cx, cy;
991 uint8_t *p, *cp;
992
993 img = &s->image[IMAGE_ROLE_ARGB];
994 cimg = &s->image[IMAGE_ROLE_COLOR_TRANSFORM];
995
996 for (y = 0; y < img->frame->height; y++) {
997 for (x = 0; x < img->frame->width; x++) {
998 cx = x >> cimg->size_reduction;
999 cy = y >> cimg->size_reduction;
1000 cp = GET_PIXEL(cimg->frame, cx, cy);
1001 p = GET_PIXEL(img->frame, x, y);
1002
1003 p[1] += color_transform_delta(cp[3], p[2]);
1004 p[3] += color_transform_delta(cp[2], p[2]) +
1005 color_transform_delta(cp[1], p[1]);
1006 }
1007 }
1008 return 0;
1009}
1010
1011static int apply_subtract_green_transform(WebPContext *s)
1012{
1013 int x, y;
1014 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
1015
1016 for (y = 0; y < img->frame->height; y++) {
1017 for (x = 0; x < img->frame->width; x++) {
1018 uint8_t *p = GET_PIXEL(img->frame, x, y);
1019 p[1] += p[2];
1020 p[3] += p[2];
1021 }
1022 }
1023 return 0;
1024}
1025
1026static int apply_color_indexing_transform(WebPContext *s)
1027{
1028 ImageContext *img;
1029 ImageContext *pal;
1030 int i, x, y;
1031 uint8_t *p;
1032
1033 img = &s->image[IMAGE_ROLE_ARGB];
1034 pal = &s->image[IMAGE_ROLE_COLOR_INDEXING];
1035
1036 if (pal->size_reduction > 0) {
1037 GetBitContext gb_g;
1038 uint8_t *line;
1039 int pixel_bits = 8 >> pal->size_reduction;
1040
1041 line = av_malloc(img->frame->linesize[0]);
1042 if (!line)
1043 return AVERROR(ENOMEM);
1044
1045 for (y = 0; y < img->frame->height; y++) {
1046 p = GET_PIXEL(img->frame, 0, y);
1047 memcpy(line, p, img->frame->linesize[0]);
1048 init_get_bits(&gb_g, line, img->frame->linesize[0] * 8);
1049 skip_bits(&gb_g, 16);
1050 i = 0;
1051 for (x = 0; x < img->frame->width; x++) {
1052 p = GET_PIXEL(img->frame, x, y);
1053 p[2] = get_bits(&gb_g, pixel_bits);
1054 i++;
1055 if (i == 1 << pal->size_reduction) {
1056 skip_bits(&gb_g, 24);
1057 i = 0;
1058 }
1059 }
1060 }
1061 av_free(line);
1062 }
1063
1064 // switch to local palette if it's worth initializing it
1065 if (img->frame->height * img->frame->width > 300) {
1066 uint8_t palette[256 * 4];
1067 const int size = pal->frame->width * 4;
1068 av_assert0(size <= 1024U);
1069 memcpy(palette, GET_PIXEL(pal->frame, 0, 0), size); // copy palette
1070 // set extra entries to transparent black
1071 memset(palette + size, 0, 256 * 4 - size);
1072 for (y = 0; y < img->frame->height; y++) {
1073 for (x = 0; x < img->frame->width; x++) {
1074 p = GET_PIXEL(img->frame, x, y);
1075 i = p[2];
1076 AV_COPY32(p, &palette[i * 4]);
1077 }
1078 }
1079 } else {
1080 for (y = 0; y < img->frame->height; y++) {
1081 for (x = 0; x < img->frame->width; x++) {
1082 p = GET_PIXEL(img->frame, x, y);
1083 i = p[2];
1084 if (i >= pal->frame->width) {
1085 AV_WB32(p, 0x00000000);
1086 } else {
1087 const uint8_t *pi = GET_PIXEL(pal->frame, i, 0);
1088 AV_COPY32(p, pi);
1089 }
1090 }
1091 }
1092 }
1093
1094 return 0;
1095}
1096
1097static int vp8_lossless_decode_frame(AVCodecContext *avctx, AVFrame *p,
1098 int *got_frame, uint8_t *data_start,
1099 unsigned int data_size, int is_alpha_chunk)
1100{
1101 WebPContext *s = avctx->priv_data;
1102 int w, h, ret, i;
1103
1104 if (!is_alpha_chunk) {
1105 s->lossless = 1;
1106 avctx->pix_fmt = AV_PIX_FMT_ARGB;
1107 }
1108
1109 ret = init_get_bits(&s->gb, data_start, data_size * 8);
1110 if (ret < 0)
1111 return ret;
1112
1113 if (!is_alpha_chunk) {
1114 if (get_bits(&s->gb, 8) != 0x2F) {
1115 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless signature\n");
1116 return AVERROR_INVALIDDATA;
1117 }
1118
1119 w = get_bits(&s->gb, 14) + 1;
1120 h = get_bits(&s->gb, 14) + 1;
1121 if (s->width && s->width != w) {
1122 av_log(avctx, AV_LOG_WARNING, "Width mismatch. %d != %d\n",
1123 s->width, w);
1124 }
1125 s->width = w;
1126 if (s->height && s->height != h) {
1127 av_log(avctx, AV_LOG_WARNING, "Height mismatch. %d != %d\n",
1128 s->width, w);
1129 }
1130 s->height = h;
1131
1132 ret = ff_set_dimensions(avctx, s->width, s->height);
1133 if (ret < 0)
1134 return ret;
1135
1136 s->has_alpha = get_bits1(&s->gb);
1137
1138 if (get_bits(&s->gb, 3) != 0x0) {
1139 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless version\n");
1140 return AVERROR_INVALIDDATA;
1141 }
1142 } else {
1143 if (!s->width || !s->height)
1144 return AVERROR_BUG;
1145 w = s->width;
1146 h = s->height;
1147 }
1148
1149 /* parse transformations */
1150 s->nb_transforms = 0;
1151 s->reduced_width = 0;
1152 while (get_bits1(&s->gb)) {
1153 enum TransformType transform = get_bits(&s->gb, 2);
1154 s->transforms[s->nb_transforms++] = transform;
1155 switch (transform) {
1156 case PREDICTOR_TRANSFORM:
1157 ret = parse_transform_predictor(s);
1158 break;
1159 case COLOR_TRANSFORM:
1160 ret = parse_transform_color(s);
1161 break;
1162 case COLOR_INDEXING_TRANSFORM:
1163 ret = parse_transform_color_indexing(s);
1164 break;
1165 }
1166 if (ret < 0)
1167 goto free_and_return;
1168 }
1169
1170 /* decode primary image */
1171 s->image[IMAGE_ROLE_ARGB].frame = p;
1172 if (is_alpha_chunk)
1173 s->image[IMAGE_ROLE_ARGB].is_alpha_primary = 1;
1174 ret = decode_entropy_coded_image(s, IMAGE_ROLE_ARGB, w, h);
1175 if (ret < 0)
1176 goto free_and_return;
1177
1178 /* apply transformations */
1179 for (i = s->nb_transforms - 1; i >= 0; i--) {
1180 switch (s->transforms[i]) {
1181 case PREDICTOR_TRANSFORM:
1182 ret = apply_predictor_transform(s);
1183 break;
1184 case COLOR_TRANSFORM:
1185 ret = apply_color_transform(s);
1186 break;
1187 case SUBTRACT_GREEN:
1188 ret = apply_subtract_green_transform(s);
1189 break;
1190 case COLOR_INDEXING_TRANSFORM:
1191 ret = apply_color_indexing_transform(s);
1192 break;
1193 }
1194 if (ret < 0)
1195 goto free_and_return;
1196 }
1197
1198 *got_frame = 1;
1199 p->pict_type = AV_PICTURE_TYPE_I;
1200 p->key_frame = 1;
1201 ret = data_size;
1202
1203free_and_return:
1204 for (i = 0; i < IMAGE_ROLE_NB; i++)
1205 image_ctx_free(&s->image[i]);
1206
1207 return ret;
1208}
1209
1210static void alpha_inverse_prediction(AVFrame *frame, enum AlphaFilter m)
1211{
1212 int x, y, ls;
1213 uint8_t *dec;
1214
1215 ls = frame->linesize[3];
1216
1217 /* filter first row using horizontal filter */
1218 dec = frame->data[3] + 1;
1219 for (x = 1; x < frame->width; x++, dec++)
1220 *dec += *(dec - 1);
1221
1222 /* filter first column using vertical filter */
1223 dec = frame->data[3] + ls;
1224 for (y = 1; y < frame->height; y++, dec += ls)
1225 *dec += *(dec - ls);
1226
1227 /* filter the rest using the specified filter */
1228 switch (m) {
1229 case ALPHA_FILTER_HORIZONTAL:
1230 for (y = 1; y < frame->height; y++) {
1231 dec = frame->data[3] + y * ls + 1;
1232 for (x = 1; x < frame->width; x++, dec++)
1233 *dec += *(dec - 1);
1234 }
1235 break;
1236 case ALPHA_FILTER_VERTICAL:
1237 for (y = 1; y < frame->height; y++) {
1238 dec = frame->data[3] + y * ls + 1;
1239 for (x = 1; x < frame->width; x++, dec++)
1240 *dec += *(dec - ls);
1241 }
1242 break;
1243 case ALPHA_FILTER_GRADIENT:
1244 for (y = 1; y < frame->height; y++) {
1245 dec = frame->data[3] + y * ls + 1;
1246 for (x = 1; x < frame->width; x++, dec++)
1247 dec[0] += av_clip_uint8(*(dec - 1) + *(dec - ls) - *(dec - ls - 1));
1248 }
1249 break;
1250 }
1251}
1252
1253static int vp8_lossy_decode_alpha(AVCodecContext *avctx, AVFrame *p,
1254 uint8_t *data_start,
1255 unsigned int data_size)
1256{
1257 WebPContext *s = avctx->priv_data;
1258 int x, y, ret;
1259
1260 if (s->alpha_compression == ALPHA_COMPRESSION_NONE) {
1261 GetByteContext gb;
1262
1263 bytestream2_init(&gb, data_start, data_size);
1264 for (y = 0; y < s->height; y++)
1265 bytestream2_get_buffer(&gb, p->data[3] + p->linesize[3] * y,
1266 s->width);
1267 } else if (s->alpha_compression == ALPHA_COMPRESSION_VP8L) {
1268 uint8_t *ap, *pp;
1269 int alpha_got_frame = 0;
1270
1271 s->alpha_frame = av_frame_alloc();
1272 if (!s->alpha_frame)
1273 return AVERROR(ENOMEM);
1274
1275 ret = vp8_lossless_decode_frame(avctx, s->alpha_frame, &alpha_got_frame,
1276 data_start, data_size, 1);
1277 if (ret < 0) {
1278 av_frame_free(&s->alpha_frame);
1279 return ret;
1280 }
1281 if (!alpha_got_frame) {
1282 av_frame_free(&s->alpha_frame);
1283 return AVERROR_INVALIDDATA;
1284 }
1285
1286 /* copy green component of alpha image to alpha plane of primary image */
1287 for (y = 0; y < s->height; y++) {
1288 ap = GET_PIXEL(s->alpha_frame, 0, y) + 2;
1289 pp = p->data[3] + p->linesize[3] * y;
1290 for (x = 0; x < s->width; x++) {
1291 *pp = *ap;
1292 pp++;
1293 ap += 4;
1294 }
1295 }
1296 av_frame_free(&s->alpha_frame);
1297 }
1298
1299 /* apply alpha filtering */
1300 if (s->alpha_filter)
1301 alpha_inverse_prediction(p, s->alpha_filter);
1302
1303 return 0;
1304}
1305
1306static int vp8_lossy_decode_frame(AVCodecContext *avctx, AVFrame *p,
1307 int *got_frame, uint8_t *data_start,
1308 unsigned int data_size)
1309{
1310 WebPContext *s = avctx->priv_data;
1311 AVPacket pkt;
1312 int ret;
1313
1314 if (!s->initialized) {
1315 ff_vp8_decode_init(avctx);
1316 s->initialized = 1;
1317 if (s->has_alpha)
1318 avctx->pix_fmt = AV_PIX_FMT_YUVA420P;
1319 }
1320 s->lossless = 0;
1321
1322 if (data_size > INT_MAX) {
1323 av_log(avctx, AV_LOG_ERROR, "unsupported chunk size\n");
1324 return AVERROR_PATCHWELCOME;
1325 }
1326
1327 av_init_packet(&pkt);
1328 pkt.data = data_start;
1329 pkt.size = data_size;
1330
1331 ret = ff_vp8_decode_frame(avctx, p, got_frame, &pkt);
1332 if (s->has_alpha) {
1333 ret = vp8_lossy_decode_alpha(avctx, p, s->alpha_data,
1334 s->alpha_data_size);
1335 if (ret < 0)
1336 return ret;
1337 }
1338 return ret;
1339}
1340
1341static int webp_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
1342 AVPacket *avpkt)
1343{
1344 AVFrame * const p = data;
1345 WebPContext *s = avctx->priv_data;
1346 GetByteContext gb;
1347 int ret;
1348 uint32_t chunk_type, chunk_size;
1349 int vp8x_flags = 0;
1350
1351 s->avctx = avctx;
1352 s->width = 0;
1353 s->height = 0;
1354 *got_frame = 0;
1355 s->has_alpha = 0;
1356 s->has_exif = 0;
1357 bytestream2_init(&gb, avpkt->data, avpkt->size);
1358
1359 if (bytestream2_get_bytes_left(&gb) < 12)
1360 return AVERROR_INVALIDDATA;
1361
1362 if (bytestream2_get_le32(&gb) != MKTAG('R', 'I', 'F', 'F')) {
1363 av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
1364 return AVERROR_INVALIDDATA;
1365 }
1366
1367 chunk_size = bytestream2_get_le32(&gb);
1368 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1369 return AVERROR_INVALIDDATA;
1370
1371 if (bytestream2_get_le32(&gb) != MKTAG('W', 'E', 'B', 'P')) {
1372 av_log(avctx, AV_LOG_ERROR, "missing WEBP tag\n");
1373 return AVERROR_INVALIDDATA;
1374 }
1375
1376 av_dict_free(&s->exif_metadata);
1377 while (bytestream2_get_bytes_left(&gb) > 0) {
1378 char chunk_str[5] = { 0 };
1379
1380 chunk_type = bytestream2_get_le32(&gb);
1381 chunk_size = bytestream2_get_le32(&gb);
1382 if (chunk_size == UINT32_MAX)
1383 return AVERROR_INVALIDDATA;
1384 chunk_size += chunk_size & 1;
1385
1386 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1387 return AVERROR_INVALIDDATA;
1388
1389 switch (chunk_type) {
1390 case MKTAG('V', 'P', '8', ' '):
1391 if (!*got_frame) {
1392 ret = vp8_lossy_decode_frame(avctx, p, got_frame,
1393 avpkt->data + bytestream2_tell(&gb),
1394 chunk_size);
1395 if (ret < 0)
1396 return ret;
1397 }
1398 bytestream2_skip(&gb, chunk_size);
1399 break;
1400 case MKTAG('V', 'P', '8', 'L'):
1401 if (!*got_frame) {
1402 ret = vp8_lossless_decode_frame(avctx, p, got_frame,
1403 avpkt->data + bytestream2_tell(&gb),
1404 chunk_size, 0);
1405 if (ret < 0)
1406 return ret;
1407 }
1408 bytestream2_skip(&gb, chunk_size);
1409 break;
1410 case MKTAG('V', 'P', '8', 'X'):
1411 vp8x_flags = bytestream2_get_byte(&gb);
1412 bytestream2_skip(&gb, 3);
1413 s->width = bytestream2_get_le24(&gb) + 1;
1414 s->height = bytestream2_get_le24(&gb) + 1;
1415 ret = av_image_check_size(s->width, s->height, 0, avctx);
1416 if (ret < 0)
1417 return ret;
1418 break;
1419 case MKTAG('A', 'L', 'P', 'H'): {
1420 int alpha_header, filter_m, compression;
1421
1422 if (!(vp8x_flags & VP8X_FLAG_ALPHA)) {
1423 av_log(avctx, AV_LOG_WARNING,
1424 "ALPHA chunk present, but alpha bit not set in the "
1425 "VP8X header\n");
1426 }
1427 if (chunk_size == 0) {
1428 av_log(avctx, AV_LOG_ERROR, "invalid ALPHA chunk size\n");
1429 return AVERROR_INVALIDDATA;
1430 }
1431 alpha_header = bytestream2_get_byte(&gb);
1432 s->alpha_data = avpkt->data + bytestream2_tell(&gb);
1433 s->alpha_data_size = chunk_size - 1;
1434 bytestream2_skip(&gb, s->alpha_data_size);
1435
1436 filter_m = (alpha_header >> 2) & 0x03;
1437 compression = alpha_header & 0x03;
1438
1439 if (compression > ALPHA_COMPRESSION_VP8L) {
1440 av_log(avctx, AV_LOG_VERBOSE,
1441 "skipping unsupported ALPHA chunk\n");
1442 } else {
1443 s->has_alpha = 1;
1444 s->alpha_compression = compression;
1445 s->alpha_filter = filter_m;
1446 }
1447
1448 break;
1449 }
1450 case MKTAG('E', 'X', 'I', 'F'): {
1451 int le, ifd_offset, exif_offset = bytestream2_tell(&gb);
1452 GetByteContext exif_gb;
1453
1454 if (s->has_exif) {
1455 av_log(avctx, AV_LOG_VERBOSE, "Ignoring extra EXIF chunk\n");
1456 goto exif_end;
1457 }
1458 if (!(vp8x_flags & VP8X_FLAG_EXIF_METADATA))
1459 av_log(avctx, AV_LOG_WARNING,
1460 "EXIF chunk present, but Exif bit not set in the "
1461 "VP8X header\n");
1462
1463 s->has_exif = 1;
1464 bytestream2_init(&exif_gb, avpkt->data + exif_offset,
1465 avpkt->size - exif_offset);
1466 if (ff_tdecode_header(&exif_gb, &le, &ifd_offset) < 0) {
1467 av_log(avctx, AV_LOG_ERROR, "invalid TIFF header "
1468 "in Exif data\n");
1469 goto exif_end;
1470 }
1471
1472 bytestream2_seek(&exif_gb, ifd_offset, SEEK_SET);
1473 if (avpriv_exif_decode_ifd(avctx, &exif_gb, le, 0, &s->exif_metadata) < 0) {
1474 av_log(avctx, AV_LOG_ERROR, "error decoding Exif data\n");
1475 goto exif_end;
1476 }
1477
1478 av_dict_copy(avpriv_frame_get_metadatap(data), s->exif_metadata, 0);
1479
1480exif_end:
1481 av_dict_free(&s->exif_metadata);
1482 bytestream2_skip(&gb, chunk_size);
1483 break;
1484 }
1485 case MKTAG('I', 'C', 'C', 'P'):
1486 case MKTAG('A', 'N', 'I', 'M'):
1487 case MKTAG('A', 'N', 'M', 'F'):
1488 case MKTAG('X', 'M', 'P', ' '):
1489 AV_WL32(chunk_str, chunk_type);
1490 av_log(avctx, AV_LOG_VERBOSE, "skipping unsupported chunk: %s\n",
1491 chunk_str);
1492 bytestream2_skip(&gb, chunk_size);
1493 break;
1494 default:
1495 AV_WL32(chunk_str, chunk_type);
1496 av_log(avctx, AV_LOG_VERBOSE, "skipping unknown chunk: %s\n",
1497 chunk_str);
1498 bytestream2_skip(&gb, chunk_size);
1499 break;
1500 }
1501 }
1502
1503 if (!*got_frame) {
1504 av_log(avctx, AV_LOG_ERROR, "image data not found\n");
1505 return AVERROR_INVALIDDATA;
1506 }
1507
1508 return avpkt->size;
1509}
1510
1511static av_cold int webp_decode_close(AVCodecContext *avctx)
1512{
1513 WebPContext *s = avctx->priv_data;
1514
1515 if (s->initialized)
1516 return ff_vp8_decode_free(avctx);
1517
1518 return 0;
1519}
1520
1521AVCodec ff_webp_decoder = {
1522 .name = "webp",
1523 .long_name = NULL_IF_CONFIG_SMALL("WebP image"),
1524 .type = AVMEDIA_TYPE_VIDEO,
1525 .id = AV_CODEC_ID_WEBP,
1526 .priv_data_size = sizeof(WebPContext),
1527 .decode = webp_decode_frame,
1528 .close = webp_decode_close,
1529 .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
1530};
ffmpeg Piment Noir Debian package repository