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Use bitstream_init8() where appropriate
[libav.git] / libavcodec / webp.c
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 Libav.
7 *
8 * Libav 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 * Libav 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 Libav; 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 * Unimplemented:
35 * - Animation
36 * - ICC profile
37 * - Exif and XMP metadata
38 */
39
40 #include "libavutil/imgutils.h"
41
42 #define BITSTREAM_READER_LE
43 #include "avcodec.h"
44 #include "bitstream.h"
45 #include "bytestream.h"
46 #include "internal.h"
47 #include "thread.h"
48 #include "vp8.h"
49
50 #define VP8X_FLAG_ANIMATION 0x02
51 #define VP8X_FLAG_XMP_METADATA 0x04
52 #define VP8X_FLAG_EXIF_METADATA 0x08
53 #define VP8X_FLAG_ALPHA 0x10
54 #define VP8X_FLAG_ICC 0x20
55
56 #define MAX_PALETTE_SIZE 256
57 #define MAX_CACHE_BITS 11
58 #define NUM_CODE_LENGTH_CODES 19
59 #define HUFFMAN_CODES_PER_META_CODE 5
60 #define NUM_LITERAL_CODES 256
61 #define NUM_LENGTH_CODES 24
62 #define NUM_DISTANCE_CODES 40
63 #define NUM_SHORT_DISTANCES 120
64 #define MAX_HUFFMAN_CODE_LENGTH 15
65
66 static const uint16_t alphabet_sizes[HUFFMAN_CODES_PER_META_CODE] = {
67 NUM_LITERAL_CODES + NUM_LENGTH_CODES,
68 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
69 NUM_DISTANCE_CODES
70 };
71
72 static const uint8_t code_length_code_order[NUM_CODE_LENGTH_CODES] = {
73 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
74 };
75
76 static const int8_t lz77_distance_offsets[NUM_SHORT_DISTANCES][2] = {
77 { 0, 1 }, { 1, 0 }, { 1, 1 }, { -1, 1 }, { 0, 2 }, { 2, 0 }, { 1, 2 }, { -1, 2 },
78 { 2, 1 }, { -2, 1 }, { 2, 2 }, { -2, 2 }, { 0, 3 }, { 3, 0 }, { 1, 3 }, { -1, 3 },
79 { 3, 1 }, { -3, 1 }, { 2, 3 }, { -2, 3 }, { 3, 2 }, { -3, 2 }, { 0, 4 }, { 4, 0 },
80 { 1, 4 }, { -1, 4 }, { 4, 1 }, { -4, 1 }, { 3, 3 }, { -3, 3 }, { 2, 4 }, { -2, 4 },
81 { 4, 2 }, { -4, 2 }, { 0, 5 }, { 3, 4 }, { -3, 4 }, { 4, 3 }, { -4, 3 }, { 5, 0 },
82 { 1, 5 }, { -1, 5 }, { 5, 1 }, { -5, 1 }, { 2, 5 }, { -2, 5 }, { 5, 2 }, { -5, 2 },
83 { 4, 4 }, { -4, 4 }, { 3, 5 }, { -3, 5 }, { 5, 3 }, { -5, 3 }, { 0, 6 }, { 6, 0 },
84 { 1, 6 }, { -1, 6 }, { 6, 1 }, { -6, 1 }, { 2, 6 }, { -2, 6 }, { 6, 2 }, { -6, 2 },
85 { 4, 5 }, { -4, 5 }, { 5, 4 }, { -5, 4 }, { 3, 6 }, { -3, 6 }, { 6, 3 }, { -6, 3 },
86 { 0, 7 }, { 7, 0 }, { 1, 7 }, { -1, 7 }, { 5, 5 }, { -5, 5 }, { 7, 1 }, { -7, 1 },
87 { 4, 6 }, { -4, 6 }, { 6, 4 }, { -6, 4 }, { 2, 7 }, { -2, 7 }, { 7, 2 }, { -7, 2 },
88 { 3, 7 }, { -3, 7 }, { 7, 3 }, { -7, 3 }, { 5, 6 }, { -5, 6 }, { 6, 5 }, { -6, 5 },
89 { 8, 0 }, { 4, 7 }, { -4, 7 }, { 7, 4 }, { -7, 4 }, { 8, 1 }, { 8, 2 }, { 6, 6 },
90 { -6, 6 }, { 8, 3 }, { 5, 7 }, { -5, 7 }, { 7, 5 }, { -7, 5 }, { 8, 4 }, { 6, 7 },
91 { -6, 7 }, { 7, 6 }, { -7, 6 }, { 8, 5 }, { 7, 7 }, { -7, 7 }, { 8, 6 }, { 8, 7 }
92 };
93
94 enum AlphaCompression {
95 ALPHA_COMPRESSION_NONE,
96 ALPHA_COMPRESSION_VP8L,
97 };
98
99 enum AlphaFilter {
100 ALPHA_FILTER_NONE,
101 ALPHA_FILTER_HORIZONTAL,
102 ALPHA_FILTER_VERTICAL,
103 ALPHA_FILTER_GRADIENT,
104 };
105
106 enum TransformType {
107 PREDICTOR_TRANSFORM = 0,
108 COLOR_TRANSFORM = 1,
109 SUBTRACT_GREEN = 2,
110 COLOR_INDEXING_TRANSFORM = 3,
111 };
112
113 enum PredictionMode {
114 PRED_MODE_BLACK,
115 PRED_MODE_L,
116 PRED_MODE_T,
117 PRED_MODE_TR,
118 PRED_MODE_TL,
119 PRED_MODE_AVG_T_AVG_L_TR,
120 PRED_MODE_AVG_L_TL,
121 PRED_MODE_AVG_L_T,
122 PRED_MODE_AVG_TL_T,
123 PRED_MODE_AVG_T_TR,
124 PRED_MODE_AVG_AVG_L_TL_AVG_T_TR,
125 PRED_MODE_SELECT,
126 PRED_MODE_ADD_SUBTRACT_FULL,
127 PRED_MODE_ADD_SUBTRACT_HALF,
128 };
129
130 enum HuffmanIndex {
131 HUFF_IDX_GREEN = 0,
132 HUFF_IDX_RED = 1,
133 HUFF_IDX_BLUE = 2,
134 HUFF_IDX_ALPHA = 3,
135 HUFF_IDX_DIST = 4
136 };
137
138 /* The structure of WebP lossless is an optional series of transformation data,
139 * followed by the primary image. The primary image also optionally contains
140 * an entropy group mapping if there are multiple entropy groups. There is a
141 * basic image type called an "entropy coded image" that is used for all of
142 * these. The type of each entropy coded image is referred to by the
143 * specification as its role. */
144 enum ImageRole {
145 /* Primary Image: Stores the actual pixels of the image. */
146 IMAGE_ROLE_ARGB,
147
148 /* Entropy Image: Defines which Huffman group to use for different areas of
149 * the primary image. */
150 IMAGE_ROLE_ENTROPY,
151
152 /* Predictors: Defines which predictor type to use for different areas of
153 * the primary image. */
154 IMAGE_ROLE_PREDICTOR,
155
156 /* Color Transform Data: Defines the color transformation for different
157 * areas of the primary image. */
158 IMAGE_ROLE_COLOR_TRANSFORM,
159
160 /* Color Index: Stored as an image of height == 1. */
161 IMAGE_ROLE_COLOR_INDEXING,
162
163 IMAGE_ROLE_NB,
164 };
165
166 typedef struct HuffReader {
167 VLC vlc; /* Huffman decoder context */
168 int simple; /* whether to use simple mode */
169 int nb_symbols; /* number of coded symbols */
170 uint16_t simple_symbols[2]; /* symbols for simple mode */
171 } HuffReader;
172
173 typedef struct ImageContext {
174 enum ImageRole role; /* role of this image */
175 AVFrame *frame; /* AVFrame for data */
176 int color_cache_bits; /* color cache size, log2 */
177 uint32_t *color_cache; /* color cache data */
178 int nb_huffman_groups; /* number of huffman groups */
179 HuffReader *huffman_groups; /* reader for each huffman group */
180 int size_reduction; /* relative size compared to primary image, log2 */
181 int is_alpha_primary;
182 } ImageContext;
183
184 typedef struct WebPContext {
185 VP8Context v; /* VP8 Context used for lossy decoding */
186 BitstreamContext bc; /* bitstream reader for main image chunk */
187 AVFrame *alpha_frame; /* AVFrame for alpha data decompressed from VP8L */
188 AVCodecContext *avctx; /* parent AVCodecContext */
189 int initialized; /* set once the VP8 context is initialized */
190 int has_alpha; /* has a separate alpha chunk */
191 enum AlphaCompression alpha_compression; /* compression type for alpha chunk */
192 enum AlphaFilter alpha_filter; /* filtering method for alpha chunk */
193 uint8_t *alpha_data; /* alpha chunk data */
194 int alpha_data_size; /* alpha chunk data size */
195 int width; /* image width */
196 int height; /* image height */
197 int lossless; /* indicates lossless or lossy */
198
199 int nb_transforms; /* number of transforms */
200 enum TransformType transforms[4]; /* transformations used in the image, in order */
201 int reduced_width; /* reduced width for index image, if applicable */
202 int nb_huffman_groups; /* number of huffman groups in the primary image */
203 ImageContext image[IMAGE_ROLE_NB]; /* image context for each role */
204 } WebPContext;
205
206 #define GET_PIXEL(frame, x, y) \
207 ((frame)->data[0] + (y) * frame->linesize[0] + 4 * (x))
208
209 #define GET_PIXEL_COMP(frame, x, y, c) \
210 (*((frame)->data[0] + (y) * frame->linesize[0] + 4 * (x) + c))
211
212 static void image_ctx_free(ImageContext *img)
213 {
214 int i, j;
215
216 av_free(img->color_cache);
217 if (img->role != IMAGE_ROLE_ARGB && !img->is_alpha_primary)
218 av_frame_free(&img->frame);
219 if (img->huffman_groups) {
220 for (i = 0; i < img->nb_huffman_groups; i++) {
221 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; j++)
222 ff_free_vlc(&img->huffman_groups[i * HUFFMAN_CODES_PER_META_CODE + j].vlc);
223 }
224 av_free(img->huffman_groups);
225 }
226 memset(img, 0, sizeof(*img));
227 }
228
229
230 /* Differs from get_vlc2() in the following ways:
231 * - codes are bit-reversed
232 * - assumes 8-bit table to make reversal simpler
233 * - assumes max depth of 2 since the max code length for WebP is 15
234 */
235 static av_always_inline int webp_get_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2])
236 {
237 int n, nb_bits;
238 unsigned int index;
239 int code;
240
241 index = bitstream_peek(bc, 8);
242 index = ff_reverse[index];
243 code = table[index][0];
244 n = table[index][1];
245
246 if (n < 0) {
247 bitstream_skip(bc, 8);
248
249 nb_bits = -n;
250
251 index = bitstream_peek(bc, nb_bits);
252 index = (ff_reverse[index] >> (8 - nb_bits)) + code;
253 code = table[index][0];
254 n = table[index][1];
255 }
256 bitstream_skip(bc, n);
257
258 return code;
259 }
260
261 static int huff_reader_get_symbol(HuffReader *r, BitstreamContext *bc)
262 {
263 if (r->simple) {
264 if (r->nb_symbols == 1)
265 return r->simple_symbols[0];
266 else
267 return r->simple_symbols[bitstream_read_bit(bc)];
268 } else
269 return webp_get_vlc(bc, r->vlc.table);
270 }
271
272 static int huff_reader_build_canonical(HuffReader *r, int *code_lengths,
273 int alphabet_size)
274 {
275 int len = 0, sym, code = 0, ret;
276 int max_code_length = 0;
277 uint16_t *codes;
278
279 /* special-case 1 symbol since the vlc reader cannot handle it */
280 for (sym = 0; sym < alphabet_size; sym++) {
281 if (code_lengths[sym] > 0) {
282 len++;
283 code = sym;
284 if (len > 1)
285 break;
286 }
287 }
288 if (len == 1) {
289 r->nb_symbols = 1;
290 r->simple_symbols[0] = code;
291 r->simple = 1;
292 return 0;
293 }
294
295 for (sym = 0; sym < alphabet_size; sym++)
296 max_code_length = FFMAX(max_code_length, code_lengths[sym]);
297
298 if (max_code_length == 0 || max_code_length > MAX_HUFFMAN_CODE_LENGTH)
299 return AVERROR(EINVAL);
300
301 codes = av_malloc(alphabet_size * sizeof(*codes));
302 if (!codes)
303 return AVERROR(ENOMEM);
304
305 code = 0;
306 r->nb_symbols = 0;
307 for (len = 1; len <= max_code_length; len++) {
308 for (sym = 0; sym < alphabet_size; sym++) {
309 if (code_lengths[sym] != len)
310 continue;
311 codes[sym] = code++;
312 r->nb_symbols++;
313 }
314 code <<= 1;
315 }
316 if (!r->nb_symbols) {
317 av_free(codes);
318 return AVERROR_INVALIDDATA;
319 }
320
321 ret = init_vlc(&r->vlc, 8, alphabet_size,
322 code_lengths, sizeof(*code_lengths), sizeof(*code_lengths),
323 codes, sizeof(*codes), sizeof(*codes), 0);
324 if (ret < 0) {
325 av_free(codes);
326 return ret;
327 }
328 r->simple = 0;
329
330 av_free(codes);
331 return 0;
332 }
333
334 static void read_huffman_code_simple(WebPContext *s, HuffReader *hc)
335 {
336 hc->nb_symbols = bitstream_read_bit(&s->bc) + 1;
337
338 if (bitstream_read_bit(&s->bc))
339 hc->simple_symbols[0] = bitstream_read(&s->bc, 8);
340 else
341 hc->simple_symbols[0] = bitstream_read_bit(&s->bc);
342
343 if (hc->nb_symbols == 2)
344 hc->simple_symbols[1] = bitstream_read(&s->bc, 8);
345
346 hc->simple = 1;
347 }
348
349 static int read_huffman_code_normal(WebPContext *s, HuffReader *hc,
350 int alphabet_size)
351 {
352 HuffReader code_len_hc = { { 0 }, 0, 0, { 0 } };
353 int *code_lengths = NULL;
354 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
355 int i, symbol, max_symbol, prev_code_len, ret;
356 int num_codes = 4 + bitstream_read(&s->bc, 4);
357
358 if (num_codes > NUM_CODE_LENGTH_CODES)
359 return AVERROR_INVALIDDATA;
360
361 for (i = 0; i < num_codes; i++)
362 code_length_code_lengths[code_length_code_order[i]] = bitstream_read(&s->bc, 3);
363
364 ret = huff_reader_build_canonical(&code_len_hc, code_length_code_lengths,
365 NUM_CODE_LENGTH_CODES);
366 if (ret < 0)
367 goto finish;
368
369 code_lengths = av_mallocz_array(alphabet_size, sizeof(*code_lengths));
370 if (!code_lengths) {
371 ret = AVERROR(ENOMEM);
372 goto finish;
373 }
374
375 if (bitstream_read_bit(&s->bc)) {
376 int bits = 2 + 2 * bitstream_read(&s->bc, 3);
377 max_symbol = 2 + bitstream_read(&s->bc, bits);
378 if (max_symbol > alphabet_size) {
379 av_log(s->avctx, AV_LOG_ERROR, "max symbol %d > alphabet size %d\n",
380 max_symbol, alphabet_size);
381 ret = AVERROR_INVALIDDATA;
382 goto finish;
383 }
384 } else {
385 max_symbol = alphabet_size;
386 }
387
388 prev_code_len = 8;
389 symbol = 0;
390 while (symbol < alphabet_size) {
391 int code_len;
392
393 if (!max_symbol--)
394 break;
395 code_len = huff_reader_get_symbol(&code_len_hc, &s->bc);
396 if (code_len < 16) {
397 /* Code length code [0..15] indicates literal code lengths. */
398 code_lengths[symbol++] = code_len;
399 if (code_len)
400 prev_code_len = code_len;
401 } else {
402 int repeat = 0, length = 0;
403 switch (code_len) {
404 case 16:
405 /* Code 16 repeats the previous non-zero value [3..6] times,
406 * i.e., 3 + ReadBits(2) times. If code 16 is used before a
407 * non-zero value has been emitted, a value of 8 is repeated. */
408 repeat = 3 + bitstream_read(&s->bc, 2);
409 length = prev_code_len;
410 break;
411 case 17:
412 /* Code 17 emits a streak of zeros [3..10], i.e.,
413 * 3 + ReadBits(3) times. */
414 repeat = 3 + bitstream_read(&s->bc, 3);
415 break;
416 case 18:
417 /* Code 18 emits a streak of zeros of length [11..138], i.e.,
418 * 11 + ReadBits(7) times. */
419 repeat = 11 + bitstream_read(&s->bc, 7);
420 break;
421 }
422 if (symbol + repeat > alphabet_size) {
423 av_log(s->avctx, AV_LOG_ERROR,
424 "invalid symbol %d + repeat %d > alphabet size %d\n",
425 symbol, repeat, alphabet_size);
426 ret = AVERROR_INVALIDDATA;
427 goto finish;
428 }
429 while (repeat-- > 0)
430 code_lengths[symbol++] = length;
431 }
432 }
433
434 ret = huff_reader_build_canonical(hc, code_lengths, alphabet_size);
435
436 finish:
437 ff_free_vlc(&code_len_hc.vlc);
438 av_free(code_lengths);
439 return ret;
440 }
441
442 static int decode_entropy_coded_image(WebPContext *s, enum ImageRole role,
443 int w, int h);
444
445 #define PARSE_BLOCK_SIZE(w, h) do { \
446 block_bits = bitstream_read(&s->bc, 3) + 2; \
447 blocks_w = FFALIGN((w), 1 << block_bits) >> block_bits; \
448 blocks_h = FFALIGN((h), 1 << block_bits) >> block_bits; \
449 } while (0)
450
451 static int decode_entropy_image(WebPContext *s)
452 {
453 ImageContext *img;
454 int ret, block_bits, width, blocks_w, blocks_h, x, y, max;
455
456 width = s->width;
457 if (s->reduced_width > 0)
458 width = s->reduced_width;
459
460 PARSE_BLOCK_SIZE(width, s->height);
461
462 ret = decode_entropy_coded_image(s, IMAGE_ROLE_ENTROPY, blocks_w, blocks_h);
463 if (ret < 0)
464 return ret;
465
466 img = &s->image[IMAGE_ROLE_ENTROPY];
467 img->size_reduction = block_bits;
468
469 /* the number of huffman groups is determined by the maximum group number
470 * coded in the entropy image */
471 max = 0;
472 for (y = 0; y < img->frame->height; y++) {
473 for (x = 0; x < img->frame->width; x++) {
474 int p0 = GET_PIXEL_COMP(img->frame, x, y, 1);
475 int p1 = GET_PIXEL_COMP(img->frame, x, y, 2);
476 int p = p0 << 8 | p1;
477 max = FFMAX(max, p);
478 }
479 }
480 s->nb_huffman_groups = max + 1;
481
482 return 0;
483 }
484
485 static int parse_transform_predictor(WebPContext *s)
486 {
487 int block_bits, blocks_w, blocks_h, ret;
488
489 PARSE_BLOCK_SIZE(s->width, s->height);
490
491 ret = decode_entropy_coded_image(s, IMAGE_ROLE_PREDICTOR, blocks_w,
492 blocks_h);
493 if (ret < 0)
494 return ret;
495
496 s->image[IMAGE_ROLE_PREDICTOR].size_reduction = block_bits;
497
498 return 0;
499 }
500
501 static int parse_transform_color(WebPContext *s)
502 {
503 int block_bits, blocks_w, blocks_h, ret;
504
505 PARSE_BLOCK_SIZE(s->width, s->height);
506
507 ret = decode_entropy_coded_image(s, IMAGE_ROLE_COLOR_TRANSFORM, blocks_w,
508 blocks_h);
509 if (ret < 0)
510 return ret;
511
512 s->image[IMAGE_ROLE_COLOR_TRANSFORM].size_reduction = block_bits;
513
514 return 0;
515 }
516
517 static int parse_transform_color_indexing(WebPContext *s)
518 {
519 ImageContext *img;
520 int width_bits, index_size, ret, x;
521 uint8_t *ct;
522
523 index_size = bitstream_read(&s->bc, 8) + 1;
524
525 if (index_size <= 2)
526 width_bits = 3;
527 else if (index_size <= 4)
528 width_bits = 2;
529 else if (index_size <= 16)
530 width_bits = 1;
531 else
532 width_bits = 0;
533
534 ret = decode_entropy_coded_image(s, IMAGE_ROLE_COLOR_INDEXING,
535 index_size, 1);
536 if (ret < 0)
537 return ret;
538
539 img = &s->image[IMAGE_ROLE_COLOR_INDEXING];
540 img->size_reduction = width_bits;
541 if (width_bits > 0)
542 s->reduced_width = (s->width + ((1 << width_bits) - 1)) >> width_bits;
543
544 /* color index values are delta-coded */
545 ct = img->frame->data[0] + 4;
546 for (x = 4; x < img->frame->width * 4; x++, ct++)
547 ct[0] += ct[-4];
548
549 return 0;
550 }
551
552 static HuffReader *get_huffman_group(WebPContext *s, ImageContext *img,
553 int x, int y)
554 {
555 ImageContext *gimg = &s->image[IMAGE_ROLE_ENTROPY];
556 int group = 0;
557
558 if (gimg->size_reduction > 0) {
559 int group_x = x >> gimg->size_reduction;
560 int group_y = y >> gimg->size_reduction;
561 int g0 = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 1);
562 int g1 = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 2);
563 group = g0 << 8 | g1;
564 }
565
566 return &img->huffman_groups[group * HUFFMAN_CODES_PER_META_CODE];
567 }
568
569 static av_always_inline void color_cache_put(ImageContext *img, uint32_t c)
570 {
571 uint32_t cache_idx = (0x1E35A7BD * c) >> (32 - img->color_cache_bits);
572 img->color_cache[cache_idx] = c;
573 }
574
575 static int decode_entropy_coded_image(WebPContext *s, enum ImageRole role,
576 int w, int h)
577 {
578 ImageContext *img;
579 HuffReader *hg;
580 int i, j, ret, x, y, width;
581
582 img = &s->image[role];
583 img->role = role;
584
585 if (!img->frame) {
586 img->frame = av_frame_alloc();
587 if (!img->frame)
588 return AVERROR(ENOMEM);
589 }
590
591 img->frame->format = AV_PIX_FMT_ARGB;
592 img->frame->width = w;
593 img->frame->height = h;
594
595 if (role == IMAGE_ROLE_ARGB && !img->is_alpha_primary) {
596 ThreadFrame pt = { .f = img->frame };
597 ret = ff_thread_get_buffer(s->avctx, &pt, 0);
598 } else
599 ret = av_frame_get_buffer(img->frame, 1);
600 if (ret < 0)
601 return ret;
602
603 if (bitstream_read_bit(&s->bc)) {
604 img->color_cache_bits = bitstream_read(&s->bc, 4);
605 if (img->color_cache_bits < 1 || img->color_cache_bits > 11) {
606 av_log(s->avctx, AV_LOG_ERROR, "invalid color cache bits: %d\n",
607 img->color_cache_bits);
608 return AVERROR_INVALIDDATA;
609 }
610 img->color_cache = av_mallocz_array(1 << img->color_cache_bits,
611 sizeof(*img->color_cache));
612 if (!img->color_cache)
613 return AVERROR(ENOMEM);
614 } else {
615 img->color_cache_bits = 0;
616 }
617
618 img->nb_huffman_groups = 1;
619 if (role == IMAGE_ROLE_ARGB && bitstream_read_bit(&s->bc)) {
620 ret = decode_entropy_image(s);
621 if (ret < 0)
622 return ret;
623 img->nb_huffman_groups = s->nb_huffman_groups;
624 }
625 img->huffman_groups = av_mallocz_array(img->nb_huffman_groups *
626 HUFFMAN_CODES_PER_META_CODE,
627 sizeof(*img->huffman_groups));
628 if (!img->huffman_groups)
629 return AVERROR(ENOMEM);
630
631 for (i = 0; i < img->nb_huffman_groups; i++) {
632 hg = &img->huffman_groups[i * HUFFMAN_CODES_PER_META_CODE];
633 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; j++) {
634 int alphabet_size = alphabet_sizes[j];
635 if (!j && img->color_cache_bits > 0)
636 alphabet_size += 1 << img->color_cache_bits;
637
638 if (bitstream_read_bit(&s->bc)) {
639 read_huffman_code_simple(s, &hg[j]);
640 } else {
641 ret = read_huffman_code_normal(s, &hg[j], alphabet_size);
642 if (ret < 0)
643 return ret;
644 }
645 }
646 }
647
648 width = img->frame->width;
649 if (role == IMAGE_ROLE_ARGB && s->reduced_width > 0)
650 width = s->reduced_width;
651
652 x = 0; y = 0;
653 while (y < img->frame->height) {
654 int v;
655
656 hg = get_huffman_group(s, img, x, y);
657 v = huff_reader_get_symbol(&hg[HUFF_IDX_GREEN], &s->bc);
658 if (v < NUM_LITERAL_CODES) {
659 /* literal pixel values */
660 uint8_t *p = GET_PIXEL(img->frame, x, y);
661 p[2] = v;
662 p[1] = huff_reader_get_symbol(&hg[HUFF_IDX_RED], &s->bc);
663 p[3] = huff_reader_get_symbol(&hg[HUFF_IDX_BLUE], &s->bc);
664 p[0] = huff_reader_get_symbol(&hg[HUFF_IDX_ALPHA], &s->bc);
665 if (img->color_cache_bits)
666 color_cache_put(img, AV_RB32(p));
667 x++;
668 if (x == width) {
669 x = 0;
670 y++;
671 }
672 } else if (v < NUM_LITERAL_CODES + NUM_LENGTH_CODES) {
673 /* LZ77 backwards mapping */
674 int prefix_code, length, distance, ref_x, ref_y;
675
676 /* parse length and distance */
677 prefix_code = v - NUM_LITERAL_CODES;
678 if (prefix_code < 4) {
679 length = prefix_code + 1;
680 } else {
681 int extra_bits = (prefix_code - 2) >> 1;
682 int offset = 2 + (prefix_code & 1) << extra_bits;
683 length = offset + bitstream_read(&s->bc, extra_bits) + 1;
684 }
685 prefix_code = huff_reader_get_symbol(&hg[HUFF_IDX_DIST], &s->bc);
686 if (prefix_code > 39) {
687 av_log(s->avctx, AV_LOG_ERROR,
688 "distance prefix code too large: %d\n", prefix_code);
689 return AVERROR_INVALIDDATA;
690 }
691 if (prefix_code < 4) {
692 distance = prefix_code + 1;
693 } else {
694 int extra_bits = prefix_code - 2 >> 1;
695 int offset = 2 + (prefix_code & 1) << extra_bits;
696 distance = offset + bitstream_read(&s->bc, extra_bits) + 1;
697 }
698
699 /* find reference location */
700 if (distance <= NUM_SHORT_DISTANCES) {
701 int xi = lz77_distance_offsets[distance - 1][0];
702 int yi = lz77_distance_offsets[distance - 1][1];
703 distance = FFMAX(1, xi + yi * width);
704 } else {
705 distance -= NUM_SHORT_DISTANCES;
706 }
707 ref_x = x;
708 ref_y = y;
709 if (distance <= x) {
710 ref_x -= distance;
711 distance = 0;
712 } else {
713 ref_x = 0;
714 distance -= x;
715 }
716 while (distance >= width) {
717 ref_y--;
718 distance -= width;
719 }
720 if (distance > 0) {
721 ref_x = width - distance;
722 ref_y--;
723 }
724 ref_x = FFMAX(0, ref_x);
725 ref_y = FFMAX(0, ref_y);
726
727 /* copy pixels
728 * source and dest regions can overlap and wrap lines, so just
729 * copy per-pixel */
730 for (i = 0; i < length; i++) {
731 uint8_t *p_ref = GET_PIXEL(img->frame, ref_x, ref_y);
732 uint8_t *p = GET_PIXEL(img->frame, x, y);
733
734 AV_COPY32(p, p_ref);
735 if (img->color_cache_bits)
736 color_cache_put(img, AV_RB32(p));
737 x++;
738 ref_x++;
739 if (x == width) {
740 x = 0;
741 y++;
742 }
743 if (ref_x == width) {
744 ref_x = 0;
745 ref_y++;
746 }
747 if (y == img->frame->height || ref_y == img->frame->height)
748 break;
749 }
750 } else {
751 /* read from color cache */
752 uint8_t *p = GET_PIXEL(img->frame, x, y);
753 int cache_idx = v - (NUM_LITERAL_CODES + NUM_LENGTH_CODES);
754
755 if (!img->color_cache_bits) {
756 av_log(s->avctx, AV_LOG_ERROR, "color cache not found\n");
757 return AVERROR_INVALIDDATA;
758 }
759 if (cache_idx >= 1 << img->color_cache_bits) {
760 av_log(s->avctx, AV_LOG_ERROR,
761 "color cache index out-of-bounds\n");
762 return AVERROR_INVALIDDATA;
763 }
764 AV_WB32(p, img->color_cache[cache_idx]);
765 x++;
766 if (x == width) {
767 x = 0;
768 y++;
769 }
770 }
771 }
772
773 return 0;
774 }
775
776 /* PRED_MODE_BLACK */
777 static void inv_predict_0(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
778 const uint8_t *p_t, const uint8_t *p_tr)
779 {
780 AV_WB32(p, 0xFF000000);
781 }
782
783 /* PRED_MODE_L */
784 static void inv_predict_1(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
785 const uint8_t *p_t, const uint8_t *p_tr)
786 {
787 AV_COPY32(p, p_l);
788 }
789
790 /* PRED_MODE_T */
791 static void inv_predict_2(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
792 const uint8_t *p_t, const uint8_t *p_tr)
793 {
794 AV_COPY32(p, p_t);
795 }
796
797 /* PRED_MODE_TR */
798 static void inv_predict_3(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
799 const uint8_t *p_t, const uint8_t *p_tr)
800 {
801 AV_COPY32(p, p_tr);
802 }
803
804 /* PRED_MODE_TL */
805 static void inv_predict_4(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
806 const uint8_t *p_t, const uint8_t *p_tr)
807 {
808 AV_COPY32(p, p_tl);
809 }
810
811 /* PRED_MODE_AVG_T_AVG_L_TR */
812 static void inv_predict_5(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
813 const uint8_t *p_t, const uint8_t *p_tr)
814 {
815 p[0] = p_t[0] + (p_l[0] + p_tr[0] >> 1) >> 1;
816 p[1] = p_t[1] + (p_l[1] + p_tr[1] >> 1) >> 1;
817 p[2] = p_t[2] + (p_l[2] + p_tr[2] >> 1) >> 1;
818 p[3] = p_t[3] + (p_l[3] + p_tr[3] >> 1) >> 1;
819 }
820
821 /* PRED_MODE_AVG_L_TL */
822 static void inv_predict_6(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
823 const uint8_t *p_t, const uint8_t *p_tr)
824 {
825 p[0] = p_l[0] + p_tl[0] >> 1;
826 p[1] = p_l[1] + p_tl[1] >> 1;
827 p[2] = p_l[2] + p_tl[2] >> 1;
828 p[3] = p_l[3] + p_tl[3] >> 1;
829 }
830
831 /* PRED_MODE_AVG_L_T */
832 static void inv_predict_7(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
833 const uint8_t *p_t, const uint8_t *p_tr)
834 {
835 p[0] = p_l[0] + p_t[0] >> 1;
836 p[1] = p_l[1] + p_t[1] >> 1;
837 p[2] = p_l[2] + p_t[2] >> 1;
838 p[3] = p_l[3] + p_t[3] >> 1;
839 }
840
841 /* PRED_MODE_AVG_TL_T */
842 static void inv_predict_8(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
843 const uint8_t *p_t, const uint8_t *p_tr)
844 {
845 p[0] = p_tl[0] + p_t[0] >> 1;
846 p[1] = p_tl[1] + p_t[1] >> 1;
847 p[2] = p_tl[2] + p_t[2] >> 1;
848 p[3] = p_tl[3] + p_t[3] >> 1;
849 }
850
851 /* PRED_MODE_AVG_T_TR */
852 static void inv_predict_9(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
853 const uint8_t *p_t, const uint8_t *p_tr)
854 {
855 p[0] = p_t[0] + p_tr[0] >> 1;
856 p[1] = p_t[1] + p_tr[1] >> 1;
857 p[2] = p_t[2] + p_tr[2] >> 1;
858 p[3] = p_t[3] + p_tr[3] >> 1;
859 }
860
861 /* PRED_MODE_AVG_AVG_L_TL_AVG_T_TR */
862 static void inv_predict_10(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
863 const uint8_t *p_t, const uint8_t *p_tr)
864 {
865 p[0] = (p_l[0] + p_tl[0] >> 1) + (p_t[0] + p_tr[0] >> 1) >> 1;
866 p[1] = (p_l[1] + p_tl[1] >> 1) + (p_t[1] + p_tr[1] >> 1) >> 1;
867 p[2] = (p_l[2] + p_tl[2] >> 1) + (p_t[2] + p_tr[2] >> 1) >> 1;
868 p[3] = (p_l[3] + p_tl[3] >> 1) + (p_t[3] + p_tr[3] >> 1) >> 1;
869 }
870
871 /* PRED_MODE_SELECT */
872 static void inv_predict_11(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
873 const uint8_t *p_t, const uint8_t *p_tr)
874 {
875 int diff = (FFABS(p_l[0] - p_tl[0]) - FFABS(p_t[0] - p_tl[0])) +
876 (FFABS(p_l[1] - p_tl[1]) - FFABS(p_t[1] - p_tl[1])) +
877 (FFABS(p_l[2] - p_tl[2]) - FFABS(p_t[2] - p_tl[2])) +
878 (FFABS(p_l[3] - p_tl[3]) - FFABS(p_t[3] - p_tl[3]));
879 if (diff <= 0)
880 AV_COPY32(p, p_t);
881 else
882 AV_COPY32(p, p_l);
883 }
884
885 /* PRED_MODE_ADD_SUBTRACT_FULL */
886 static void inv_predict_12(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
887 const uint8_t *p_t, const uint8_t *p_tr)
888 {
889 p[0] = av_clip_uint8(p_l[0] + p_t[0] - p_tl[0]);
890 p[1] = av_clip_uint8(p_l[1] + p_t[1] - p_tl[1]);
891 p[2] = av_clip_uint8(p_l[2] + p_t[2] - p_tl[2]);
892 p[3] = av_clip_uint8(p_l[3] + p_t[3] - p_tl[3]);
893 }
894
895 static av_always_inline uint8_t clamp_add_subtract_half(int a, int b, int c)
896 {
897 int d = a + b >> 1;
898 return av_clip_uint8(d + (d - c) / 2);
899 }
900
901 /* PRED_MODE_ADD_SUBTRACT_HALF */
902 static void inv_predict_13(uint8_t *p, const uint8_t *p_l, const uint8_t *p_tl,
903 const uint8_t *p_t, const uint8_t *p_tr)
904 {
905 p[0] = clamp_add_subtract_half(p_l[0], p_t[0], p_tl[0]);
906 p[1] = clamp_add_subtract_half(p_l[1], p_t[1], p_tl[1]);
907 p[2] = clamp_add_subtract_half(p_l[2], p_t[2], p_tl[2]);
908 p[3] = clamp_add_subtract_half(p_l[3], p_t[3], p_tl[3]);
909 }
910
911 typedef void (*inv_predict_func)(uint8_t *p, const uint8_t *p_l,
912 const uint8_t *p_tl, const uint8_t *p_t,
913 const uint8_t *p_tr);
914
915 static const inv_predict_func inverse_predict[14] = {
916 inv_predict_0, inv_predict_1, inv_predict_2, inv_predict_3,
917 inv_predict_4, inv_predict_5, inv_predict_6, inv_predict_7,
918 inv_predict_8, inv_predict_9, inv_predict_10, inv_predict_11,
919 inv_predict_12, inv_predict_13,
920 };
921
922 static void inverse_prediction(AVFrame *frame, enum PredictionMode m, int x, int y)
923 {
924 uint8_t *dec, *p_l, *p_tl, *p_t, *p_tr;
925 uint8_t p[4];
926
927 dec = GET_PIXEL(frame, x, y);
928 p_l = GET_PIXEL(frame, x - 1, y);
929 p_tl = GET_PIXEL(frame, x - 1, y - 1);
930 p_t = GET_PIXEL(frame, x, y - 1);
931 if (x == frame->width - 1)
932 p_tr = GET_PIXEL(frame, 0, y);
933 else
934 p_tr = GET_PIXEL(frame, x + 1, y - 1);
935
936 inverse_predict[m](p, p_l, p_tl, p_t, p_tr);
937
938 dec[0] += p[0];
939 dec[1] += p[1];
940 dec[2] += p[2];
941 dec[3] += p[3];
942 }
943
944 static int apply_predictor_transform(WebPContext *s)
945 {
946 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
947 ImageContext *pimg = &s->image[IMAGE_ROLE_PREDICTOR];
948 int x, y;
949
950 for (y = 0; y < img->frame->height; y++) {
951 for (x = 0; x < img->frame->width; x++) {
952 int tx = x >> pimg->size_reduction;
953 int ty = y >> pimg->size_reduction;
954 enum PredictionMode m = GET_PIXEL_COMP(pimg->frame, tx, ty, 2);
955
956 if (x == 0) {
957 if (y == 0)
958 m = PRED_MODE_BLACK;
959 else
960 m = PRED_MODE_T;
961 } else if (y == 0)
962 m = PRED_MODE_L;
963
964 if (m > 13) {
965 av_log(s->avctx, AV_LOG_ERROR,
966 "invalid predictor mode: %d\n", m);
967 return AVERROR_INVALIDDATA;
968 }
969 inverse_prediction(img->frame, m, x, y);
970 }
971 }
972 return 0;
973 }
974
975 static av_always_inline uint8_t color_transform_delta(uint8_t color_pred,
976 uint8_t color)
977 {
978 return (int)ff_u8_to_s8(color_pred) * ff_u8_to_s8(color) >> 5;
979 }
980
981 static int apply_color_transform(WebPContext *s)
982 {
983 ImageContext *img, *cimg;
984 int x, y, cx, cy;
985 uint8_t *p, *cp;
986
987 img = &s->image[IMAGE_ROLE_ARGB];
988 cimg = &s->image[IMAGE_ROLE_COLOR_TRANSFORM];
989
990 for (y = 0; y < img->frame->height; y++) {
991 for (x = 0; x < img->frame->width; x++) {
992 cx = x >> cimg->size_reduction;
993 cy = y >> cimg->size_reduction;
994 cp = GET_PIXEL(cimg->frame, cx, cy);
995 p = GET_PIXEL(img->frame, x, y);
996
997 p[1] += color_transform_delta(cp[3], p[2]);
998 p[3] += color_transform_delta(cp[2], p[2]) +
999 color_transform_delta(cp[1], p[1]);
1000 }
1001 }
1002 return 0;
1003 }
1004
1005 static int apply_subtract_green_transform(WebPContext *s)
1006 {
1007 int x, y;
1008 ImageContext *img = &s->image[IMAGE_ROLE_ARGB];
1009
1010 for (y = 0; y < img->frame->height; y++) {
1011 for (x = 0; x < img->frame->width; x++) {
1012 uint8_t *p = GET_PIXEL(img->frame, x, y);
1013 p[1] += p[2];
1014 p[3] += p[2];
1015 }
1016 }
1017 return 0;
1018 }
1019
1020 static int apply_color_indexing_transform(WebPContext *s)
1021 {
1022 ImageContext *img;
1023 ImageContext *pal;
1024 int i, x, y;
1025 uint8_t *p, *pi;
1026
1027 img = &s->image[IMAGE_ROLE_ARGB];
1028 pal = &s->image[IMAGE_ROLE_COLOR_INDEXING];
1029
1030 if (pal->size_reduction > 0) {
1031 BitstreamContext bc_g;
1032 uint8_t *line;
1033 int pixel_bits = 8 >> pal->size_reduction;
1034
1035 line = av_malloc(img->frame->linesize[0]);
1036 if (!line)
1037 return AVERROR(ENOMEM);
1038
1039 for (y = 0; y < img->frame->height; y++) {
1040 p = GET_PIXEL(img->frame, 0, y);
1041 memcpy(line, p, img->frame->linesize[0]);
1042 bitstream_init8(&bc_g, line, img->frame->linesize[0]);
1043 bitstream_skip(&bc_g, 16);
1044 i = 0;
1045 for (x = 0; x < img->frame->width; x++) {
1046 p = GET_PIXEL(img->frame, x, y);
1047 p[2] = bitstream_read(&bc_g, pixel_bits);
1048 i++;
1049 if (i == 1 << pal->size_reduction) {
1050 bitstream_skip(&bc_g, 24);
1051 i = 0;
1052 }
1053 }
1054 }
1055 av_free(line);
1056 }
1057
1058 for (y = 0; y < img->frame->height; y++) {
1059 for (x = 0; x < img->frame->width; x++) {
1060 p = GET_PIXEL(img->frame, x, y);
1061 i = p[2];
1062 if (i >= pal->frame->width) {
1063 av_log(s->avctx, AV_LOG_ERROR, "invalid palette index %d\n", i);
1064 return AVERROR_INVALIDDATA;
1065 }
1066 pi = GET_PIXEL(pal->frame, i, 0);
1067 AV_COPY32(p, pi);
1068 }
1069 }
1070
1071 return 0;
1072 }
1073
1074 static int vp8_lossless_decode_frame(AVCodecContext *avctx, AVFrame *p,
1075 int *got_frame, uint8_t *data_start,
1076 unsigned int data_size, int is_alpha_chunk)
1077 {
1078 WebPContext *s = avctx->priv_data;
1079 int w, h, ret, i, used;
1080
1081 if (!is_alpha_chunk) {
1082 s->lossless = 1;
1083 avctx->pix_fmt = AV_PIX_FMT_ARGB;
1084 }
1085
1086 ret = bitstream_init8(&s->bc, data_start, data_size);
1087 if (ret < 0)
1088 return ret;
1089
1090 if (!is_alpha_chunk) {
1091 if (bitstream_read(&s->bc, 8) != 0x2F) {
1092 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless signature\n");
1093 return AVERROR_INVALIDDATA;
1094 }
1095
1096 w = bitstream_read(&s->bc, 14) + 1;
1097 h = bitstream_read(&s->bc, 14) + 1;
1098 if (s->width && s->width != w) {
1099 av_log(avctx, AV_LOG_WARNING, "Width mismatch. %d != %d\n",
1100 s->width, w);
1101 }
1102 s->width = w;
1103 if (s->height && s->height != h) {
1104 av_log(avctx, AV_LOG_WARNING, "Height mismatch. %d != %d\n",
1105 s->width, w);
1106 }
1107 s->height = h;
1108
1109 ret = ff_set_dimensions(avctx, s->width, s->height);
1110 if (ret < 0)
1111 return ret;
1112
1113 s->has_alpha = bitstream_read_bit(&s->bc);
1114
1115 if (bitstream_read(&s->bc, 3) != 0x0) {
1116 av_log(avctx, AV_LOG_ERROR, "Invalid WebP Lossless version\n");
1117 return AVERROR_INVALIDDATA;
1118 }
1119 } else {
1120 if (!s->width || !s->height)
1121 return AVERROR_BUG;
1122 w = s->width;
1123 h = s->height;
1124 }
1125
1126 /* parse transformations */
1127 s->nb_transforms = 0;
1128 s->reduced_width = 0;
1129 used = 0;
1130 while (bitstream_read_bit(&s->bc)) {
1131 enum TransformType transform = bitstream_read(&s->bc, 2);
1132 s->transforms[s->nb_transforms++] = transform;
1133 if (used & (1 << transform)) {
1134 av_log(avctx, AV_LOG_ERROR, "Transform %d used more than once\n",
1135 transform);
1136 ret = AVERROR_INVALIDDATA;
1137 goto free_and_return;
1138 }
1139 used |= (1 << transform);
1140 switch (transform) {
1141 case PREDICTOR_TRANSFORM:
1142 ret = parse_transform_predictor(s);
1143 break;
1144 case COLOR_TRANSFORM:
1145 ret = parse_transform_color(s);
1146 break;
1147 case COLOR_INDEXING_TRANSFORM:
1148 ret = parse_transform_color_indexing(s);
1149 break;
1150 }
1151 if (ret < 0)
1152 goto free_and_return;
1153 }
1154
1155 /* decode primary image */
1156 s->image[IMAGE_ROLE_ARGB].frame = p;
1157 if (is_alpha_chunk)
1158 s->image[IMAGE_ROLE_ARGB].is_alpha_primary = 1;
1159 ret = decode_entropy_coded_image(s, IMAGE_ROLE_ARGB, w, h);
1160 if (ret < 0)
1161 goto free_and_return;
1162
1163 /* apply transformations */
1164 for (i = s->nb_transforms - 1; i >= 0; i--) {
1165 switch (s->transforms[i]) {
1166 case PREDICTOR_TRANSFORM:
1167 ret = apply_predictor_transform(s);
1168 break;
1169 case COLOR_TRANSFORM:
1170 ret = apply_color_transform(s);
1171 break;
1172 case SUBTRACT_GREEN:
1173 ret = apply_subtract_green_transform(s);
1174 break;
1175 case COLOR_INDEXING_TRANSFORM:
1176 ret = apply_color_indexing_transform(s);
1177 break;
1178 }
1179 if (ret < 0)
1180 goto free_and_return;
1181 }
1182
1183 *got_frame = 1;
1184 p->pict_type = AV_PICTURE_TYPE_I;
1185 p->key_frame = 1;
1186 ret = data_size;
1187
1188 free_and_return:
1189 for (i = 0; i < IMAGE_ROLE_NB; i++)
1190 image_ctx_free(&s->image[i]);
1191
1192 return ret;
1193 }
1194
1195 static void alpha_inverse_prediction(AVFrame *frame, enum AlphaFilter m)
1196 {
1197 int x, y, ls;
1198 uint8_t *dec;
1199
1200 ls = frame->linesize[3];
1201
1202 /* filter first row using horizontal filter */
1203 dec = frame->data[3] + 1;
1204 for (x = 1; x < frame->width; x++, dec++)
1205 *dec += *(dec - 1);
1206
1207 /* filter first column using vertical filter */
1208 dec = frame->data[3] + ls;
1209 for (y = 1; y < frame->height; y++, dec += ls)
1210 *dec += *(dec - ls);
1211
1212 /* filter the rest using the specified filter */
1213 switch (m) {
1214 case ALPHA_FILTER_HORIZONTAL:
1215 for (y = 1; y < frame->height; y++) {
1216 dec = frame->data[3] + y * ls + 1;
1217 for (x = 1; x < frame->width; x++, dec++)
1218 *dec += *(dec - 1);
1219 }
1220 break;
1221 case ALPHA_FILTER_VERTICAL:
1222 for (y = 1; y < frame->height; y++) {
1223 dec = frame->data[3] + y * ls + 1;
1224 for (x = 1; x < frame->width; x++, dec++)
1225 *dec += *(dec - ls);
1226 }
1227 break;
1228 case ALPHA_FILTER_GRADIENT:
1229 for (y = 1; y < frame->height; y++) {
1230 dec = frame->data[3] + y * ls + 1;
1231 for (x = 1; x < frame->width; x++, dec++)
1232 dec[0] += av_clip_uint8(*(dec - 1) + *(dec - ls) - *(dec - ls - 1));
1233 }
1234 break;
1235 }
1236 }
1237
1238 static int vp8_lossy_decode_alpha(AVCodecContext *avctx, AVFrame *p,
1239 uint8_t *data_start,
1240 unsigned int data_size)
1241 {
1242 WebPContext *s = avctx->priv_data;
1243 int x, y, ret;
1244
1245 if (s->alpha_compression == ALPHA_COMPRESSION_NONE) {
1246 GetByteContext gb;
1247
1248 bytestream2_init(&gb, data_start, data_size);
1249 for (y = 0; y < s->height; y++)
1250 bytestream2_get_buffer(&gb, p->data[3] + p->linesize[3] * y,
1251 s->width);
1252 } else if (s->alpha_compression == ALPHA_COMPRESSION_VP8L) {
1253 uint8_t *ap, *pp;
1254 int alpha_got_frame = 0;
1255
1256 s->alpha_frame = av_frame_alloc();
1257 if (!s->alpha_frame)
1258 return AVERROR(ENOMEM);
1259
1260 ret = vp8_lossless_decode_frame(avctx, s->alpha_frame, &alpha_got_frame,
1261 data_start, data_size, 1);
1262 if (ret < 0) {
1263 av_frame_free(&s->alpha_frame);
1264 return ret;
1265 }
1266 if (!alpha_got_frame) {
1267 av_frame_free(&s->alpha_frame);
1268 return AVERROR_INVALIDDATA;
1269 }
1270
1271 /* copy green component of alpha image to alpha plane of primary image */
1272 for (y = 0; y < s->height; y++) {
1273 ap = GET_PIXEL(s->alpha_frame, 0, y) + 2;
1274 pp = p->data[3] + p->linesize[3] * y;
1275 for (x = 0; x < s->width; x++) {
1276 *pp = *ap;
1277 pp++;
1278 ap += 4;
1279 }
1280 }
1281 av_frame_free(&s->alpha_frame);
1282 }
1283
1284 /* apply alpha filtering */
1285 if (s->alpha_filter)
1286 alpha_inverse_prediction(p, s->alpha_filter);
1287
1288 return 0;
1289 }
1290
1291 static int vp8_lossy_decode_frame(AVCodecContext *avctx, AVFrame *p,
1292 int *got_frame, uint8_t *data_start,
1293 unsigned int data_size)
1294 {
1295 WebPContext *s = avctx->priv_data;
1296 AVPacket pkt;
1297 int ret;
1298
1299 if (!s->initialized) {
1300 ff_vp8_decode_init(avctx);
1301 s->initialized = 1;
1302 if (s->has_alpha)
1303 avctx->pix_fmt = AV_PIX_FMT_YUVA420P;
1304 }
1305 s->lossless = 0;
1306
1307 if (data_size > INT_MAX) {
1308 av_log(avctx, AV_LOG_ERROR, "unsupported chunk size\n");
1309 return AVERROR_PATCHWELCOME;
1310 }
1311
1312 av_init_packet(&pkt);
1313 pkt.data = data_start;
1314 pkt.size = data_size;
1315
1316 ret = ff_vp8_decode_frame(avctx, p, got_frame, &pkt);
1317 if (s->has_alpha) {
1318 ret = vp8_lossy_decode_alpha(avctx, p, s->alpha_data,
1319 s->alpha_data_size);
1320 if (ret < 0)
1321 return ret;
1322 }
1323 return ret;
1324 }
1325
1326 static int webp_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
1327 AVPacket *avpkt)
1328 {
1329 AVFrame * const p = data;
1330 WebPContext *s = avctx->priv_data;
1331 GetByteContext gb;
1332 int ret;
1333 uint32_t chunk_type, chunk_size;
1334 int vp8x_flags = 0;
1335
1336 s->avctx = avctx;
1337 s->width = 0;
1338 s->height = 0;
1339 *got_frame = 0;
1340 s->has_alpha = 0;
1341 bytestream2_init(&gb, avpkt->data, avpkt->size);
1342
1343 if (bytestream2_get_bytes_left(&gb) < 12)
1344 return AVERROR_INVALIDDATA;
1345
1346 if (bytestream2_get_le32(&gb) != MKTAG('R', 'I', 'F', 'F')) {
1347 av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
1348 return AVERROR_INVALIDDATA;
1349 }
1350
1351 chunk_size = bytestream2_get_le32(&gb);
1352 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1353 return AVERROR_INVALIDDATA;
1354
1355 if (bytestream2_get_le32(&gb) != MKTAG('W', 'E', 'B', 'P')) {
1356 av_log(avctx, AV_LOG_ERROR, "missing WEBP tag\n");
1357 return AVERROR_INVALIDDATA;
1358 }
1359
1360 while (bytestream2_get_bytes_left(&gb) > 8) {
1361 char chunk_str[5] = { 0 };
1362
1363 chunk_type = bytestream2_get_le32(&gb);
1364 chunk_size = bytestream2_get_le32(&gb);
1365 if (chunk_size == UINT32_MAX)
1366 return AVERROR_INVALIDDATA;
1367 chunk_size += chunk_size & 1;
1368
1369 if (bytestream2_get_bytes_left(&gb) < chunk_size)
1370 return AVERROR_INVALIDDATA;
1371
1372 switch (chunk_type) {
1373 case MKTAG('V', 'P', '8', ' '):
1374 if (!*got_frame) {
1375 ret = vp8_lossy_decode_frame(avctx, p, got_frame,
1376 avpkt->data + bytestream2_tell(&gb),
1377 chunk_size);
1378 if (ret < 0)
1379 return ret;
1380 }
1381 bytestream2_skip(&gb, chunk_size);
1382 break;
1383 case MKTAG('V', 'P', '8', 'L'):
1384 if (!*got_frame) {
1385 ret = vp8_lossless_decode_frame(avctx, p, got_frame,
1386 avpkt->data + bytestream2_tell(&gb),
1387 chunk_size, 0);
1388 if (ret < 0)
1389 return ret;
1390 }
1391 bytestream2_skip(&gb, chunk_size);
1392 break;
1393 case MKTAG('V', 'P', '8', 'X'):
1394 vp8x_flags = bytestream2_get_byte(&gb);
1395 bytestream2_skip(&gb, 3);
1396 s->width = bytestream2_get_le24(&gb) + 1;
1397 s->height = bytestream2_get_le24(&gb) + 1;
1398 ret = av_image_check_size(s->width, s->height, 0, avctx);
1399 if (ret < 0)
1400 return ret;
1401 break;
1402 case MKTAG('A', 'L', 'P', 'H'): {
1403 int alpha_header, filter_m, compression;
1404
1405 if (!(vp8x_flags & VP8X_FLAG_ALPHA)) {
1406 av_log(avctx, AV_LOG_WARNING,
1407 "ALPHA chunk present, but alpha bit not set in the "
1408 "VP8X header\n");
1409 }
1410 if (chunk_size == 0) {
1411 av_log(avctx, AV_LOG_ERROR, "invalid ALPHA chunk size\n");
1412 return AVERROR_INVALIDDATA;
1413 }
1414 alpha_header = bytestream2_get_byte(&gb);
1415 s->alpha_data = avpkt->data + bytestream2_tell(&gb);
1416 s->alpha_data_size = chunk_size - 1;
1417 bytestream2_skip(&gb, s->alpha_data_size);
1418
1419 filter_m = (alpha_header >> 2) & 0x03;
1420 compression = alpha_header & 0x03;
1421
1422 if (compression > ALPHA_COMPRESSION_VP8L) {
1423 av_log(avctx, AV_LOG_VERBOSE,
1424 "skipping unsupported ALPHA chunk\n");
1425 } else {
1426 s->has_alpha = 1;
1427 s->alpha_compression = compression;
1428 s->alpha_filter = filter_m;
1429 }
1430
1431 break;
1432 }
1433 case MKTAG('I', 'C', 'C', 'P'):
1434 case MKTAG('A', 'N', 'I', 'M'):
1435 case MKTAG('A', 'N', 'M', 'F'):
1436 case MKTAG('E', 'X', 'I', 'F'):
1437 case MKTAG('X', 'M', 'P', ' '):
1438 AV_WL32(chunk_str, chunk_type);
1439 av_log(avctx, AV_LOG_VERBOSE, "skipping unsupported chunk: %s\n",
1440 chunk_str);
1441 bytestream2_skip(&gb, chunk_size);
1442 break;
1443 default:
1444 AV_WL32(chunk_str, chunk_type);
1445 av_log(avctx, AV_LOG_VERBOSE, "skipping unknown chunk: %s\n",
1446 chunk_str);
1447 bytestream2_skip(&gb, chunk_size);
1448 break;
1449 }
1450 }
1451
1452 if (!*got_frame) {
1453 av_log(avctx, AV_LOG_ERROR, "image data not found\n");
1454 return AVERROR_INVALIDDATA;
1455 }
1456
1457 return avpkt->size;
1458 }
1459
1460 static av_cold int webp_decode_close(AVCodecContext *avctx)
1461 {
1462 WebPContext *s = avctx->priv_data;
1463
1464 if (s->initialized)
1465 return ff_vp8_decode_free(avctx);
1466
1467 return 0;
1468 }
1469
1470 AVCodec ff_webp_decoder = {
1471 .name = "webp",
1472 .long_name = NULL_IF_CONFIG_SMALL("WebP image"),
1473 .type = AVMEDIA_TYPE_VIDEO,
1474 .id = AV_CODEC_ID_WEBP,
1475 .priv_data_size = sizeof(WebPContext),
1476 .decode = webp_decode_frame,
1477 .close = webp_decode_close,
1478 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
1479 };
Libav master