FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/apngdec.c
Date: 2024-02-16 17:37:06
Exec Total Coverage
Lines: 166 213 77.9%
Functions: 5 5 100.0%
Branches: 104 170 61.2%

Line Branch Exec Source
1 /*
2 * APNG demuxer
3 * Copyright (c) 2014 Benoit Fouet
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * APNG demuxer.
25 * @see https://wiki.mozilla.org/APNG_Specification
26 * @see http://www.w3.org/TR/PNG
27 */
28
29 #include "avformat.h"
30 #include "avio_internal.h"
31 #include "internal.h"
32 #include "libavutil/imgutils.h"
33 #include "libavutil/intreadwrite.h"
34 #include "libavutil/opt.h"
35 #include "libavcodec/apng.h"
36 #include "libavcodec/png.h"
37 #include "libavcodec/bytestream.h"
38
39 #define DEFAULT_APNG_FPS 15
40
41 typedef struct APNGDemuxContext {
42 const AVClass *class;
43
44 int max_fps;
45 int default_fps;
46
47 int pkt_duration;
48
49 int is_key_frame;
50
51 /*
52 * loop options
53 */
54 int ignore_loop;
55 uint32_t num_frames;
56 uint32_t num_play;
57 uint32_t cur_loop;
58 } APNGDemuxContext;
59
60 /*
61 * To be a valid APNG file, we mandate, in this order:
62 * PNGSIG
63 * IHDR
64 * ...
65 * acTL
66 * ...
67 * IDAT
68 */
69 7023 static int apng_probe(const AVProbeData *p)
70 {
71 GetByteContext gb;
72 7023 int state = 0;
73 uint32_t len, tag;
74
75 7023 bytestream2_init(&gb, p->buf, p->buf_size);
76
77
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7023 if (bytestream2_get_be64(&gb) != PNGSIG)
78 6978 return 0;
79
80 for (;;) {
81 196 len = bytestream2_get_be32(&gb);
82
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196 if (len > 0x7fffffff)
83 return 0;
84
85 196 tag = bytestream2_get_le32(&gb);
86 /* we don't check IDAT size, as this is the last tag
87 * we check, and it may be larger than the probe buffer */
88
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196 if (tag != MKTAG('I', 'D', 'A', 'T') &&
89
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155 len + 4 > bytestream2_get_bytes_left(&gb))
90 4 return 0;
91
92
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192 switch (tag) {
93 45 case MKTAG('I', 'H', 'D', 'R'):
94
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45 if (len != 13)
95 return 0;
96
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45 if (av_image_check_size(bytestream2_get_be32(&gb), bytestream2_get_be32(&gb), 0, NULL))
97 return 0;
98 45 bytestream2_skip(&gb, 9);
99 45 state++;
100 45 break;
101 8 case MKTAG('a', 'c', 'T', 'L'):
102
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8 if (state != 1 ||
103
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8 len != 8 ||
104 8 bytestream2_get_be32(&gb) == 0) /* 0 is not a valid value for number of frames */
105 return 0;
106 8 bytestream2_skip(&gb, 8);
107 8 state++;
108 8 break;
109 41 case MKTAG('I', 'D', 'A', 'T'):
110
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41 if (state != 2)
111 33 return 0;
112 8 goto end;
113 98 default:
114 /* skip other tags */
115 98 bytestream2_skip(&gb, len + 4);
116 98 break;
117 }
118 }
119
120 8 end:
121 8 return AVPROBE_SCORE_MAX;
122 }
123
124 17 static int append_extradata(AVCodecParameters *par, AVIOContext *pb, int len)
125 {
126 17 int previous_size = par->extradata_size;
127 int new_size, ret;
128 uint8_t *new_extradata;
129
130
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17 if (len > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE - previous_size)
131 return AVERROR_INVALIDDATA;
132
133 17 new_size = previous_size + len;
134 17 new_extradata = av_realloc(par->extradata, new_size + AV_INPUT_BUFFER_PADDING_SIZE);
135
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17 if (!new_extradata)
136 return AVERROR(ENOMEM);
137 17 memset(new_extradata + new_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
138 17 par->extradata = new_extradata;
139 17 par->extradata_size = new_size;
140
141
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17 if ((ret = ffio_read_size(pb, par->extradata + previous_size, len)) < 0)
142 return ret;
143
144 17 return previous_size;
145 }
146
147 9 static int apng_read_header(AVFormatContext *s)
148 {
149 9 APNGDemuxContext *ctx = s->priv_data;
150 9 AVIOContext *pb = s->pb;
151 uint32_t len, tag;
152 AVStream *st;
153 9 int acTL_found = 0;
154 int64_t ret;
155
156 /* verify PNGSIG */
157
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9 if (avio_rb64(pb) != PNGSIG)
158 return AVERROR_INVALIDDATA;
159
160 /* parse IHDR (must be first chunk) */
161 9 len = avio_rb32(pb);
162 9 tag = avio_rl32(pb);
163
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9 if (len != 13 || tag != MKTAG('I', 'H', 'D', 'R'))
164 return AVERROR_INVALIDDATA;
165
166 9 st = avformat_new_stream(s, NULL);
167
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9 if (!st)
168 return AVERROR(ENOMEM);
169
170 /* set the timebase to something large enough (1/100,000 of second)
171 * to hopefully cope with all sane frame durations */
172 9 avpriv_set_pts_info(st, 64, 1, 100000);
173 9 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
174 9 st->codecpar->codec_id = AV_CODEC_ID_APNG;
175 9 st->codecpar->width = avio_rb32(pb);
176 9 st->codecpar->height = avio_rb32(pb);
177
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9 if ((ret = av_image_check_size(st->codecpar->width, st->codecpar->height, 0, s)) < 0)
178 return ret;
179
180 /* extradata will contain every chunk up to the first fcTL (excluded) */
181 9 ret = ff_alloc_extradata(st->codecpar, len + 12);
182
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9 if (ret < 0)
183 return ret;
184 9 AV_WB32(st->codecpar->extradata, len);
185 9 AV_WL32(st->codecpar->extradata+4, tag);
186 9 AV_WB32(st->codecpar->extradata+8, st->codecpar->width);
187 9 AV_WB32(st->codecpar->extradata+12, st->codecpar->height);
188
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9 if ((ret = ffio_read_size(pb, st->codecpar->extradata + 16, 9)) < 0)
189 return ret;
190
191 while (1) {
192
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26 if (acTL_found && ctx->num_play != 1) {
193 10 int64_t size = avio_size(pb);
194 10 int64_t offset = avio_tell(pb);
195
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10 if (size < 0) {
196 return size;
197
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10 } else if (offset < 0) {
198 return offset;
199
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10 } else if ((ret = ffio_ensure_seekback(pb, size - offset)) < 0) {
200 av_log(s, AV_LOG_WARNING, "Could not ensure seekback, will not loop\n");
201 ctx->num_play = 1;
202 }
203 }
204
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26 if ((ctx->num_play == 1 || !acTL_found) &&
205
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16 ((ret = ffio_ensure_seekback(pb, 4 /* len */ + 4 /* tag */)) < 0))
206 return ret;
207
208 26 len = avio_rb32(pb);
209
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26 if (len > INT_MAX - 12)
210 return AVERROR_INVALIDDATA;
211
212 26 tag = avio_rl32(pb);
213
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26 switch (tag) {
214 9 case MKTAG('a', 'c', 'T', 'L'):
215
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9 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
216
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9 (ret = append_extradata(st->codecpar, pb, len + 12)) < 0)
217 return ret;
218 9 acTL_found = 1;
219 9 ctx->num_frames = AV_RB32(st->codecpar->extradata + ret + 8);
220 9 ctx->num_play = AV_RB32(st->codecpar->extradata + ret + 12);
221 9 av_log(s, AV_LOG_DEBUG, "num_frames: %"PRIu32", num_play: %"PRIu32"\n",
222 ctx->num_frames, ctx->num_play);
223 9 break;
224 9 case MKTAG('f', 'c', 'T', 'L'):
225
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9 if (!acTL_found || len != APNG_FCTL_CHUNK_SIZE) {
226 return AVERROR_INVALIDDATA;
227 }
228
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9 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0)
229 return ret;
230 9 return 0;
231 8 default:
232
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8 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
233
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8 (ret = append_extradata(st->codecpar, pb, len + 12)) < 0)
234 return ret;
235 }
236 }
237 }
238
239 318 static int decode_fctl_chunk(AVFormatContext *s, APNGDemuxContext *ctx, AVPacket *pkt)
240 {
241 uint32_t sequence_number, width, height, x_offset, y_offset;
242 uint16_t delay_num, delay_den;
243 uint8_t dispose_op, blend_op;
244
245 318 sequence_number = avio_rb32(s->pb);
246 318 width = avio_rb32(s->pb);
247 318 height = avio_rb32(s->pb);
248 318 x_offset = avio_rb32(s->pb);
249 318 y_offset = avio_rb32(s->pb);
250 318 delay_num = avio_rb16(s->pb);
251 318 delay_den = avio_rb16(s->pb);
252 318 dispose_op = avio_r8(s->pb);
253 318 blend_op = avio_r8(s->pb);
254 318 avio_skip(s->pb, 4); /* crc */
255
256 /* default is hundredths of seconds */
257
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318 if (!delay_den)
258 delay_den = 100;
259
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318 if (!delay_num || (ctx->max_fps && delay_den / delay_num > ctx->max_fps)) {
260 delay_num = 1;
261 delay_den = ctx->default_fps;
262 }
263 318 ctx->pkt_duration = av_rescale_q(delay_num,
264 318 (AVRational){ 1, delay_den },
265 318 s->streams[0]->time_base);
266
267 318 av_log(s, AV_LOG_DEBUG, "%s: "
268 "sequence_number: %"PRId32", "
269 "width: %"PRIu32", "
270 "height: %"PRIu32", "
271 "x_offset: %"PRIu32", "
272 "y_offset: %"PRIu32", "
273 "delay_num: %"PRIu16", "
274 "delay_den: %"PRIu16", "
275 "dispose_op: %d, "
276 "blend_op: %d\n",
277 __func__,
278 sequence_number,
279 width,
280 height,
281 x_offset,
282 y_offset,
283 delay_num,
284 delay_den,
285 dispose_op,
286 blend_op);
287
288
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318 if (width != s->streams[0]->codecpar->width ||
289
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218 height != s->streams[0]->codecpar->height ||
290
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218 x_offset != 0 ||
291 y_offset != 0) {
292
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100 if (sequence_number == 0 ||
293
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100 x_offset >= s->streams[0]->codecpar->width ||
294
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100 width > s->streams[0]->codecpar->width - x_offset ||
295
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100 y_offset >= s->streams[0]->codecpar->height ||
296
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100 height > s->streams[0]->codecpar->height - y_offset)
297 return AVERROR_INVALIDDATA;
298 100 ctx->is_key_frame = 0;
299 } else {
300
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218 if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS)
301 dispose_op = APNG_DISPOSE_OP_BACKGROUND;
302
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218 ctx->is_key_frame = dispose_op == APNG_DISPOSE_OP_BACKGROUND ||
303 blend_op == APNG_BLEND_OP_SOURCE;
304 }
305
306 318 return 0;
307 }
308
309 332 static int apng_read_packet(AVFormatContext *s, AVPacket *pkt)
310 {
311 332 APNGDemuxContext *ctx = s->priv_data;
312 int64_t ret;
313 int64_t size;
314 332 AVIOContext *pb = s->pb;
315 uint32_t len, tag;
316
317 /*
318 * fcTL chunk length, in bytes:
319 * 4 (length)
320 * 4 (tag)
321 * 26 (actual chunk)
322 * 4 (crc) bytes
323 * and needed next:
324 * 4 (length)
325 * 4 (tag (must be fdAT or IDAT))
326 */
327 /* if num_play is not 1, then the seekback is already guaranteed */
328
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332 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 46)) < 0)
329 return ret;
330
331 332 len = avio_rb32(pb);
332 332 tag = avio_rl32(pb);
333
334
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332 if (avio_feof(pb))
335 return AVERROR_EOF;
336
337
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332 switch (tag) {
338 318 case MKTAG('f', 'c', 'T', 'L'):
339
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318 if (len != APNG_FCTL_CHUNK_SIZE)
340 332 return AVERROR_INVALIDDATA;
341
342
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318 if ((ret = decode_fctl_chunk(s, ctx, pkt)) < 0)
343 return ret;
344
345 /* fcTL must precede fdAT or IDAT */
346 318 len = avio_rb32(pb);
347 318 tag = avio_rl32(pb);
348
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318 if (len > 0x7fffffff ||
349
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9 tag != MKTAG('f', 'd', 'A', 'T') &&
350 tag != MKTAG('I', 'D', 'A', 'T'))
351 return AVERROR_INVALIDDATA;
352
353 318 size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */;
354
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318 if (size > INT_MAX)
355 return AVERROR(EINVAL);
356
357
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318 if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0 ||
358
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318 (ret = av_append_packet(pb, pkt, size)) < 0)
359 return ret;
360
361
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318 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
362 return ret;
363
364 318 len = avio_rb32(pb);
365 318 tag = avio_rl32(pb);
366
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5129 while (tag &&
367
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9313 tag != MKTAG('f', 'c', 'T', 'L') &&
368 tag != MKTAG('I', 'E', 'N', 'D')) {
369
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4493 if (len > 0x7fffffff)
370 return AVERROR_INVALIDDATA;
371
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4493 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
372
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4493 (ret = av_append_packet(pb, pkt, len + 12)) < 0)
373 return ret;
374
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4493 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
375 return ret;
376 4493 len = avio_rb32(pb);
377 4493 tag = avio_rl32(pb);
378 }
379
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318 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0)
380 return ret;
381
382
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318 if (ctx->is_key_frame)
383 217 pkt->flags |= AV_PKT_FLAG_KEY;
384 318 pkt->pts = pkt->dts = AV_NOPTS_VALUE;
385 318 pkt->duration = ctx->pkt_duration;
386 318 return ret;
387 14 case MKTAG('I', 'E', 'N', 'D'):
388 14 ctx->cur_loop++;
389
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14 if (ctx->ignore_loop || ctx->num_play >= 1 && ctx->cur_loop == ctx->num_play) {
390 14 avio_seek(pb, -8, SEEK_CUR);
391 14 return AVERROR_EOF;
392 }
393 if ((ret = avio_seek(pb, s->streams[0]->codecpar->extradata_size + 8, SEEK_SET)) < 0)
394 return ret;
395 return 0;
396 default:
397 avpriv_request_sample(s, "In-stream tag=%s (0x%08"PRIX32") len=%"PRIu32,
398 av_fourcc2str(tag), tag, len);
399 avio_skip(pb, len + 4);
400 }
401
402 /* Handle the unsupported yet cases */
403 return AVERROR_PATCHWELCOME;
404 }
405
406 static const AVOption options[] = {
407 { "ignore_loop", "ignore loop setting" , offsetof(APNGDemuxContext, ignore_loop),
408 AV_OPT_TYPE_BOOL, { .i64 = 1 } , 0, 1 , AV_OPT_FLAG_DECODING_PARAM },
409 { "max_fps" , "maximum framerate (0 is no limit)" , offsetof(APNGDemuxContext, max_fps),
410 AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
411 { "default_fps", "default framerate (0 is as fast as possible)", offsetof(APNGDemuxContext, default_fps),
412 AV_OPT_TYPE_INT, { .i64 = DEFAULT_APNG_FPS }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
413 { NULL },
414 };
415
416 static const AVClass demuxer_class = {
417 .class_name = "APNG demuxer",
418 .item_name = av_default_item_name,
419 .option = options,
420 .version = LIBAVUTIL_VERSION_INT,
421 .category = AV_CLASS_CATEGORY_DEMUXER,
422 };
423
424 const AVInputFormat ff_apng_demuxer = {
425 .name = "apng",
426 .long_name = NULL_IF_CONFIG_SMALL("Animated Portable Network Graphics"),
427 .priv_data_size = sizeof(APNGDemuxContext),
428 .read_probe = apng_probe,
429 .read_header = apng_read_header,
430 .read_packet = apng_read_packet,
431 .flags = AVFMT_GENERIC_INDEX,
432 .priv_class = &demuxer_class,
433 };
434